radar: pass 18 — W1 re-test: events 5th federation consumer (agenda merge, runtime-list trust like mod); inject-fed-sx seam now 5/5

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.claude/scheduled_tasks.lock

@@ -1 +1 @@
-{"sessionId":"31c80255-eb92-43e4-8997-84ad84e27326","pid":90960,"procStart":"564684","acquiredAt":1777049890282}
+{"sessionId":"bf20a443-9df8-4cb9-932e-8c6f4c4625c2","pid":1303602,"procStart":"253831081","acquiredAt":1779865895644}

.mcp.json

@@ -2,7 +2,7 @@
   "mcpServers": {
     "sx-tree": {
       "type": "stdio",
-      "command": "./hosts/ocaml/_build/default/bin/mcp_tree.exe"
+      "command": "/root/rose-ash/hosts/ocaml/_build/default/bin/mcp_tree.exe"
     },
     "rose-ash-services": {
       "type": "stdio",

lib/apl/conformance.conf

@@ -0,0 +1,63 @@
+# APL conformance config — sourced by lib/guest/conformance.sh.
+
+LANG_NAME=apl
+MODE=counters
+COUNTERS_PASS=apl-test-pass
+COUNTERS_FAIL=apl-test-fail
+TIMEOUT_PER_SUITE=300
+
+PRELOADS=(
+  spec/stdlib.sx
+  lib/r7rs.sx
+  lib/apl/runtime.sx
+  lib/apl/tokenizer.sx
+  lib/apl/parser.sx
+  lib/apl/transpile.sx
+  lib/apl/test-harness.sx
+)
+
+SUITES=(
+  "structural:lib/apl/tests/structural.sx"
+  "operators:lib/apl/tests/operators.sx"
+  "dfn:lib/apl/tests/dfn.sx"
+  "tradfn:lib/apl/tests/tradfn.sx"
+  "valence:lib/apl/tests/valence.sx"
+  "programs:lib/apl/tests/programs.sx"
+  "system:lib/apl/tests/system.sx"
+  "idioms:lib/apl/tests/idioms.sx"
+  "eval-ops:lib/apl/tests/eval-ops.sx"
+  "pipeline:lib/apl/tests/pipeline.sx"
+)
+
+emit_scoreboard_json() {
+  local n=${#GC_NAMES[@]} i sep
+  printf '{\n'
+  printf '  "suites": {\n'
+  for ((i=0; i<n; i++)); do
+    sep=","; [ $i -eq $((n-1)) ] && sep=""
+    printf '    "%s": {"pass": %d, "fail": %d}%s\n' \
+      "${GC_NAMES[$i]}" "${GC_PASS[$i]}" "${GC_FAIL[$i]}" "$sep"
+  done
+  printf '  },\n'
+  printf '  "total_pass": %d,\n' "$GC_TOTAL_PASS"
+  printf '  "total_fail": %d,\n' "$GC_TOTAL_FAIL"
+  printf '  "total": %d\n' "$GC_TOTAL"
+  printf '}\n'
+}
+
+emit_scoreboard_md() {
+  local n=${#GC_NAMES[@]} i
+  printf '# APL Conformance Scoreboard\n\n'
+  printf '_Generated by `lib/apl/conformance.sh`_\n\n'
+  printf '| Suite | Pass | Fail | Total |\n'
+  printf '|-------|-----:|-----:|------:|\n'
+  for ((i=0; i<n; i++)); do
+    printf '| %s | %d | %d | %d |\n' \
+      "${GC_NAMES[$i]}" "${GC_PASS[$i]}" "${GC_FAIL[$i]}" "${GC_TOTAL_S[$i]}"
+  done
+  printf '| **Total** | **%d** | **%d** | **%d** |\n' "$GC_TOTAL_PASS" "$GC_TOTAL_FAIL" "$GC_TOTAL"
+  printf '\n'
+  printf '## Notes\n\n'
+  printf '%s\n' '- Suites use the standard `apl-test name got expected` framework loaded against `lib/apl/runtime.sx` + `lib/apl/transpile.sx`.'
+  printf '%s\n' '- `lib/apl/tests/parse.sx` and `lib/apl/tests/scalar.sx` use their own self-contained frameworks and are excluded from this scoreboard.'
+}

lib/apl/conformance.sh

@@ -1,116 +1,5 @@
 #!/usr/bin/env bash
-# lib/apl/conformance.sh — run APL test suites, emit scoreboard.json + scoreboard.md.
-
-set -uo pipefail
-cd "$(git rev-parse --show-toplevel)"
-
-SX_SERVER="${SX_SERVER:-/root/rose-ash/hosts/ocaml/_build/default/bin/sx_server.exe}"
-if [ ! -x "$SX_SERVER" ]; then
-  SX_SERVER="hosts/ocaml/_build/default/bin/sx_server.exe"
-fi
-if [ ! -x "$SX_SERVER" ]; then
-  echo "ERROR: sx_server.exe not found." >&2
-  exit 1
-fi
-
-SUITES=(structural operators dfn tradfn valence programs system idioms eval-ops pipeline)
-
-OUT_JSON="lib/apl/scoreboard.json"
-OUT_MD="lib/apl/scoreboard.md"
-
-run_suite() {
-  local suite=$1
-  local file="lib/apl/tests/${suite}.sx"
-  local TMP
-  TMP=$(mktemp)
-  cat > "$TMP" << EPOCHS
-(epoch 1)
-(load "spec/stdlib.sx")
-(load "lib/r7rs.sx")
-(load "lib/apl/runtime.sx")
-(load "lib/apl/tokenizer.sx")
-(load "lib/apl/parser.sx")
-(load "lib/apl/transpile.sx")
-(epoch 2)
-(eval "(define apl-test-pass 0)")
-(eval "(define apl-test-fail 0)")
-(eval "(define apl-test (fn (name got expected) (if (= got expected) (set! apl-test-pass (+ apl-test-pass 1)) (set! apl-test-fail (+ apl-test-fail 1)))))")
-(epoch 3)
-(load "${file}")
-(epoch 4)
-(eval "(list apl-test-pass apl-test-fail)")
-EPOCHS
-
-  local OUTPUT
-  OUTPUT=$(timeout 300 "$SX_SERVER" < "$TMP" 2>/dev/null)
-  rm -f "$TMP"
-
-  local LINE
-  LINE=$(echo "$OUTPUT" | awk '/^\(ok-len 4 / {getline; print; exit}')
-  if [ -z "$LINE" ]; then
-    LINE=$(echo "$OUTPUT" | grep -E '^\(ok 4 \([0-9]+ [0-9]+\)\)' | tail -1 \
-            | sed -E 's/^\(ok 4 //; s/\)$//')
-  fi
-
-  local P F
-  P=$(echo "$LINE" | sed -E 's/^\(([0-9]+) ([0-9]+)\).*/\1/')
-  F=$(echo "$LINE" | sed -E 's/^\(([0-9]+) ([0-9]+)\).*/\2/')
-  P=${P:-0}
-  F=${F:-0}
-  echo "${P} ${F}"
-}
-
-declare -A SUITE_PASS
-declare -A SUITE_FAIL
-TOTAL_PASS=0
-TOTAL_FAIL=0
-
-echo "Running APL conformance suite..." >&2
-for s in "${SUITES[@]}"; do
-  read -r p f < <(run_suite "$s")
-  SUITE_PASS[$s]=$p
-  SUITE_FAIL[$s]=$f
-  TOTAL_PASS=$((TOTAL_PASS + p))
-  TOTAL_FAIL=$((TOTAL_FAIL + f))
-  printf "  %-12s %d/%d\n" "$s" "$p" "$((p+f))" >&2
-done
-
-# scoreboard.json
-{
-  printf '{\n'
-  printf '  "suites": {\n'
-  first=1
-  for s in "${SUITES[@]}"; do
-    if [ $first -eq 0 ]; then printf ',\n'; fi
-    printf '    "%s": {"pass": %d, "fail": %d}' "$s" "${SUITE_PASS[$s]}" "${SUITE_FAIL[$s]}"
-    first=0
-  done
-  printf '\n  },\n'
-  printf '  "total_pass": %d,\n' "$TOTAL_PASS"
-  printf '  "total_fail": %d,\n' "$TOTAL_FAIL"
-  printf '  "total": %d\n' "$((TOTAL_PASS + TOTAL_FAIL))"
-  printf '}\n'
-} > "$OUT_JSON"
-
-# scoreboard.md
-{
-  printf '# APL Conformance Scoreboard\n\n'
-  printf '_Generated by `lib/apl/conformance.sh`_\n\n'
-  printf '| Suite | Pass | Fail | Total |\n'
-  printf '|-------|-----:|-----:|------:|\n'
-  for s in "${SUITES[@]}"; do
-    p=${SUITE_PASS[$s]}
-    f=${SUITE_FAIL[$s]}
-    printf '| %s | %d | %d | %d |\n' "$s" "$p" "$f" "$((p+f))"
-  done
-  printf '| **Total** | **%d** | **%d** | **%d** |\n' "$TOTAL_PASS" "$TOTAL_FAIL" "$((TOTAL_PASS + TOTAL_FAIL))"
-  printf '\n'
-  printf '## Notes\n\n'
-  printf '%s\n' '- Suites use the standard `apl-test name got expected` framework loaded against `lib/apl/runtime.sx` + `lib/apl/transpile.sx`.'
-  printf '%s\n' '- `lib/apl/tests/parse.sx` and `lib/apl/tests/scalar.sx` use their own self-contained frameworks and are excluded from this scoreboard.'
-} > "$OUT_MD"
-
-echo "Wrote $OUT_JSON and $OUT_MD" >&2
-echo "Total: $TOTAL_PASS pass, $TOTAL_FAIL fail" >&2
-
-[ "$TOTAL_FAIL" -eq 0 ]
+# lib/apl/conformance.sh — APL conformance via the shared guest driver.
+# Config lives in lib/apl/conformance.conf (MODE=counters). Override the binary
+# with SX_SERVER=path/to/sx_server.exe bash lib/apl/conformance.sh
+exec bash "$(dirname "$0")/../guest/conformance.sh" "$(dirname "$0")/conformance.conf" "$@"

lib/apl/scoreboard.json

@@ -9,9 +9,9 @@
     "system": {"pass": 13, "fail": 0},
     "idioms": {"pass": 64, "fail": 0},
     "eval-ops": {"pass": 14, "fail": 0},
-    "pipeline": {"pass": 40, "fail": 0}
+    "pipeline": {"pass": 152, "fail": 0}
   },
-  "total_pass": 450,
+  "total_pass": 562,
   "total_fail": 0,
-  "total": 450
+  "total": 562
 }

lib/apl/scoreboard.md

@@ -13,8 +13,8 @@ _Generated by `lib/apl/conformance.sh`_
 | system | 13 | 0 | 13 |
 | idioms | 64 | 0 | 64 |
 | eval-ops | 14 | 0 | 14 |
-| pipeline | 40 | 0 | 40 |
-| **Total** | **450** | **0** | **450** |
+| pipeline | 152 | 0 | 152 |
+| **Total** | **562** | **0** | **562** |
 
 ## Notes
 

lib/apl/test-harness.sx

@@ -0,0 +1,15 @@
+; lib/apl/test-harness.sx — counters + assertion fn for the shared conformance
+; driver (lib/guest/conformance.sh, MODE=counters). Loaded as a PRELOAD so each
+; suite starts from a fresh 0/0; suites call (apl-test name got expected).
+
+(define apl-test-pass 0)
+(define apl-test-fail 0)
+
+(define
+  apl-test
+  (fn
+    (name got expected)
+    (if
+      (= got expected)
+      (set! apl-test-pass (+ apl-test-pass 1))
+      (set! apl-test-fail (+ apl-test-fail 1)))))

lib/erlang/runtime.sx

@@ -956,118 +956,8 @@
         (= ty "nil") (er-mk-nil)
         :else v))))
 
-;; ── HTTP request/response marshaling (Step 8b-start) ────────────
-;; The native `http-listen` primitive hands the handler an SX dict
-;;   {:method :path :query :headers :body}
-;; and expects an SX dict back
-;;   {:status :headers :body}
-;; This layer converts so Erlang handlers see proper proplists:
-;;   [{method, <<"GET">>}, {path, <<"/foo">>}, {query, <<>>},
-;;    {headers, [{<<"content-type">>, <<"text/plain">>}, ...]},
-;;    {body, <<...>>}]
-;; Headers ride as a nested proplist with binary keys — header names
-;; are arbitrary user input, so they stay out of the atom table. The
-;; outer request keys (method/path/query/headers/body) are fixed and
-;; small, so they become atoms (cheap to pattern-match against).
 
-(define er-of-sx-deep
-  (fn (v)
-    (cond
-      (= (type-of v) "dict") (er-dict-to-header-proplist v)
-      :else (er-of-sx v))))
 
-(define er-dict-to-header-proplist
-  (fn (d)
-    (let ((ks (keys d)) (out (er-mk-nil)))
-      (for-each
-        (fn (i)
-          (let ((idx (- (- (len ks) 1) i)))
-            (let ((k (nth ks idx)))
-              (let ((v (get d k)))
-                (set!
-                  out
-                  (er-mk-cons
-                    (er-mk-tuple
-                      (list
-                        (er-mk-binary (map char->integer (string->list k)))
-                        (er-of-sx-deep v)))
-                    out))))))
-        (range 0 (len ks)))
-      out)))
-
-(define er-request-dict-to-proplist
-  (fn (d)
-    (cond
-      (not (= (type-of d) "dict")) (er-of-sx d)
-      :else
-        (let ((ks (keys d)) (out (er-mk-nil)))
-          (for-each
-            (fn (i)
-              (let ((idx (- (- (len ks) 1) i)))
-                (let ((k (nth ks idx)))
-                  (let ((v (get d k)))
-                    (set!
-                      out
-                      (er-mk-cons
-                        (er-mk-tuple
-                          (list (er-mk-atom k) (er-of-sx-deep v)))
-                        out))))))
-            (range 0 (len ks)))
-          out))))
-
-;; Inverse: handler's proplist response -> SX dict for native send.
-;; Value rules:
-;;   Erlang binary   -> SX string (bytes joined)
-;;   Erlang integer  -> SX number passthrough
-;;   Erlang cons of 2-tuples -> nested SX dict (e.g. headers)
-;;   Erlang cons (other shapes) -> SX list via er-to-sx
-;;   anything else   -> er-to-sx passthrough
-
-(define er-proplist-2tuple?
-  (fn (v)
-    (cond
-      (er-nil? v) true
-      (er-cons? v)
-        (let ((h (get v :head)))
-          (cond
-            (and (er-tuple? h) (= (len (get h :elements)) 2))
-              (er-proplist-2tuple? (get v :tail))
-            :else false))
-      :else false)))
-
-(define er-to-sx-deep
-  (fn (v)
-    (cond
-      (er-binary? v) (list->string (map integer->char (get v :bytes)))
-      (and (er-cons? v) (er-proplist-2tuple? v)) (er-proplist-to-dict v)
-      :else (er-to-sx v))))
-
-(define er-proplist-to-dict
-  (fn (pl)
-    (let ((d (dict)))
-      (er-proplist-fill! pl d)
-      d)))
-
-(define er-proplist-fill!
-  (fn (pl d)
-    (cond
-      (er-nil? pl) nil
-      (er-cons? pl)
-        (let ((head (get pl :head)) (tail (get pl :tail)))
-          (cond
-            (and (er-tuple? head) (= (len (get head :elements)) 2))
-              (let ((kv (get head :elements)))
-                (let ((k (nth kv 0)) (v (nth kv 1)))
-                  (let ((key-str
-                          (cond
-                            (er-atom? k) (get k :name)
-                            (er-binary? k)
-                              (list->string (map integer->char (get k :bytes)))
-                            :else (str k))))
-                    (dict-set! d key-str (er-to-sx-deep v))
-                    (er-proplist-fill! tail d))))
-            :else (er-proplist-fill! tail d)))
-      :else nil)))
 
 ;; Load an Erlang module declaration. Source must start with
 ;; `-module(Name).` and contain function definitions. Functions
@@ -1578,26 +1468,9 @@
 ;; entry is keyed by "Module/Name/Arity"; multi-arity BIFs register
 ;; once per arity. Called eagerly at the end of runtime.sx so the
 ;; registry is ready before any erlang-eval-ast call.
-(define
-  er-bif-http-listen
-  (fn
-    (vs)
-    (let
-      ((port (nth vs 0)) (handler (nth vs 1)))
-      (cond
-        (not (= (type-of port) "number"))
-        (raise (er-mk-error-marker (er-mk-atom "badarg")))
-        (not (er-fun? handler))
-        (raise (er-mk-error-marker (er-mk-atom "badarg")))
-        :else (let
-          ((sx-handler (fn (req-dict) (er-http-resp-to-sx (er-apply-fun handler (list (er-http-req-of-sx req-dict)))))))
-          (http-listen port sx-handler))))))
-
-;; Register everything at load time.
-(define
-  er-register-builtin-bifs!
-  (fn
-    ()
+(define er-register-builtin-bifs!
+  (fn ()
+    ;; erlang module — type predicates (all pure)
     (er-register-pure-bif! "erlang" "is_integer" 1 er-bif-is-integer)
     (er-register-pure-bif! "erlang" "is_atom" 1 er-bif-is-atom)
     (er-register-pure-bif! "erlang" "is_list" 1 er-bif-is-list)
@@ -1606,61 +1479,27 @@
     (er-register-pure-bif! "erlang" "is_float" 1 er-bif-is-float)
     (er-register-pure-bif! "erlang" "is_boolean" 1 er-bif-is-boolean)
     (er-register-pure-bif! "erlang" "is_pid" 1 er-bif-is-pid)
-    (er-register-pure-bif!
-      "erlang"
-      "is_reference"
-      1
-      er-bif-is-reference)
+    (er-register-pure-bif! "erlang" "is_reference" 1 er-bif-is-reference)
     (er-register-pure-bif! "erlang" "is_binary" 1 er-bif-is-binary)
-    (er-register-pure-bif!
-      "erlang"
-      "is_function"
-      1
-      er-bif-is-function)
-    (er-register-pure-bif!
-      "erlang"
-      "is_function"
-      2
-      er-bif-is-function)
+    (er-register-pure-bif! "erlang" "is_function" 1 er-bif-is-function)
+    (er-register-pure-bif! "erlang" "is_function" 2 er-bif-is-function)
+    ;; erlang module — pure data ops
     (er-register-pure-bif! "erlang" "length" 1 er-bif-length)
     (er-register-pure-bif! "erlang" "hd" 1 er-bif-hd)
     (er-register-pure-bif! "erlang" "tl" 1 er-bif-tl)
     (er-register-pure-bif! "erlang" "element" 2 er-bif-element)
     (er-register-pure-bif! "erlang" "tuple_size" 1 er-bif-tuple-size)
     (er-register-pure-bif! "erlang" "byte_size" 1 er-bif-byte-size)
-    (er-register-pure-bif!
-      "erlang"
-      "atom_to_list"
-      1
-      er-bif-atom-to-list)
-    (er-register-pure-bif!
-      "erlang"
-      "list_to_atom"
-      1
-      er-bif-list-to-atom)
+    (er-register-pure-bif! "erlang" "atom_to_list" 1 er-bif-atom-to-list)
+    (er-register-pure-bif! "erlang" "list_to_atom" 1 er-bif-list-to-atom)
     (er-register-pure-bif! "erlang" "abs" 1 er-bif-abs)
     (er-register-pure-bif! "erlang" "min" 2 er-bif-min)
     (er-register-pure-bif! "erlang" "max" 2 er-bif-max)
-    (er-register-pure-bif!
-      "erlang"
-      "tuple_to_list"
-      1
-      er-bif-tuple-to-list)
-    (er-register-pure-bif!
-      "erlang"
-      "list_to_tuple"
-      1
-      er-bif-list-to-tuple)
-    (er-register-pure-bif!
-      "erlang"
-      "integer_to_list"
-      1
-      er-bif-integer-to-list)
-    (er-register-pure-bif!
-      "erlang"
-      "list_to_integer"
-      1
-      er-bif-list-to-integer)
+    (er-register-pure-bif! "erlang" "tuple_to_list" 1 er-bif-tuple-to-list)
+    (er-register-pure-bif! "erlang" "list_to_tuple" 1 er-bif-list-to-tuple)
+    (er-register-pure-bif! "erlang" "integer_to_list" 1 er-bif-integer-to-list)
+    (er-register-pure-bif! "erlang" "list_to_integer" 1 er-bif-list-to-integer)
+    ;; erlang module — process / runtime (side-effecting)
     (er-register-bif! "erlang" "self" 0 er-bif-self)
     (er-register-bif! "erlang" "spawn" 1 er-bif-spawn)
     (er-register-bif! "erlang" "spawn" 3 er-bif-spawn)
@@ -1676,16 +1515,12 @@
     (er-register-bif! "erlang" "unregister" 1 er-bif-unregister)
     (er-register-bif! "erlang" "whereis" 1 er-bif-whereis)
     (er-register-bif! "erlang" "registered" 0 er-bif-registered)
-    (er-register-bif!
-      "erlang"
-      "throw"
-      1
+    ;; erlang module — exception raising (modelled as side-effecting)
+    (er-register-bif! "erlang" "throw" 1
       (fn (vs) (raise (er-mk-throw-marker (er-bif-arg1 vs "throw")))))
-    (er-register-bif!
-      "erlang"
-      "error"
-      1
+    (er-register-bif! "erlang" "error" 1
       (fn (vs) (raise (er-mk-error-marker (er-bif-arg1 vs "error")))))
+    ;; lists module — all pure
     (er-register-pure-bif! "lists" "reverse" 1 er-bif-lists-reverse)
     (er-register-pure-bif! "lists" "map" 2 er-bif-lists-map)
     (er-register-pure-bif! "lists" "foldl" 3 er-bif-lists-foldl)
@@ -1699,13 +1534,11 @@
     (er-register-pure-bif! "lists" "filter" 2 er-bif-lists-filter)
     (er-register-pure-bif! "lists" "any" 2 er-bif-lists-any)
     (er-register-pure-bif! "lists" "all" 2 er-bif-lists-all)
-    (er-register-pure-bif!
-      "lists"
-      "duplicate"
-      2
-      er-bif-lists-duplicate)
+    (er-register-pure-bif! "lists" "duplicate" 2 er-bif-lists-duplicate)
+    ;; io module — side-effecting (writes to io buffer)
     (er-register-bif! "io" "format" 1 er-bif-io-format)
     (er-register-bif! "io" "format" 2 er-bif-io-format)
+    ;; ets module — side-effecting (mutates table state)
     (er-register-bif! "ets" "new" 2 er-bif-ets-new)
     (er-register-bif! "ets" "insert" 2 er-bif-ets-insert)
     (er-register-bif! "ets" "lookup" 2 er-bif-ets-lookup)
@@ -1713,88 +1546,82 @@
     (er-register-bif! "ets" "delete" 2 er-bif-ets-delete)
     (er-register-bif! "ets" "tab2list" 1 er-bif-ets-tab2list)
     (er-register-bif! "ets" "info" 2 er-bif-ets-info)
+    ;; code module — side-effecting (mutates module registry, kills procs)
     (er-register-bif! "code" "load_binary" 3 er-bif-code-load-binary)
     (er-register-bif! "code" "purge" 1 er-bif-code-purge)
     (er-register-bif! "code" "soft_purge" 1 er-bif-code-soft-purge)
     (er-register-bif! "code" "which" 1 er-bif-code-which)
     (er-register-bif! "code" "is_loaded" 1 er-bif-code-is-loaded)
     (er-register-bif! "code" "all_loaded" 0 er-bif-code-all-loaded)
+    ;; file module
     (er-register-bif! "file" "read_file" 1 er-bif-file-read-file)
     (er-register-bif! "file" "write_file" 2 er-bif-file-write-file)
     (er-register-bif! "file" "delete" 1 er-bif-file-delete)
+    ;; Phase 8 FFI — host-primitive BIFs (loops/fed-prims)
     (er-register-pure-bif! "crypto" "hash" 2 er-bif-crypto-hash)
     (er-register-pure-bif! "cid" "from_bytes" 1 er-bif-cid-from-bytes)
     (er-register-pure-bif! "cid" "to_string" 1 er-bif-cid-to-string)
-    (define
-      er-bif-binary-to-list
-      (fn
-        (vs)
-        (let
-          ((v (nth vs 0)))
-          (cond
-            (not (er-binary? v))
-            (raise (er-mk-error-marker (er-mk-atom "badarg")))
-            :else (let
-              ((bs (get v :bytes)) (out (er-mk-nil)))
-              (for-each
-                (fn
-                  (i)
-                  (set!
-                    out
-                    (er-mk-cons (nth bs (- (- (len bs) 1) i)) out)))
-                (range 0 (len bs)))
-              out)))))
-    (define
-      er-iolist-walk!
-      (fn
-        (v acc fail)
-        (cond
-          (nth fail 0)
-          nil
-          (er-nil? v)
-          nil
-          (er-cons? v)
-          (do
-            (er-iolist-walk! (get v :head) acc fail)
+
+;; ── binary_to_list / list_to_binary (Step 3b — term codec) ──────
+;; Standard Erlang semantics:
+;;   binary_to_list(<<B1,B2,...>>) -> [B1, B2, ...]   (Erlang cons of ints)
+;;   list_to_binary(IoList)        -> <<...>>         (flattens nested
+;;     iolists; elements are byte ints 0-255 or binaries)
+;; Bad arg / out-of-range byte / non-iolist element -> error:badarg.
+
+(define er-bif-binary-to-list
+  (fn (vs)
+    (let ((v (nth vs 0)))
+      (cond
+        (not (er-binary? v))
+          (raise (er-mk-error-marker (er-mk-atom "badarg")))
+        :else
+          (let ((bs (get v :bytes)) (out (er-mk-nil)))
+            (for-each
+              (fn (i)
+                (set! out (er-mk-cons (nth bs (- (- (len bs) 1) i)) out)))
+              (range 0 (len bs)))
+            out)))))
+
+;; Walk an Erlang iolist, appending bytes to `acc` (a mutable SX list).
+;; Accepts: nil, cons-of-X, binary, integer in 0..255. Anything else
+;; signals failure by setting (nth fail 0) to true.
+(define er-iolist-walk!
+  (fn (v acc fail)
+    (cond
+      (nth fail 0) nil
+      (er-nil? v) nil
+      (er-cons? v)
+        (do (er-iolist-walk! (get v :head) acc fail)
             (er-iolist-walk! (get v :tail) acc fail))
-          (er-binary? v)
-          (for-each
-            (fn (i) (append! acc (nth (get v :bytes) i)))
-            (range 0 (len (get v :bytes))))
-          (= (type-of v) "number")
-          (cond
-            (and (>= v 0) (<= v 255))
-            (append! acc v)
-            :else (set-nth! fail 0 true))
-          :else (set-nth! fail 0 true))))
-    (define
-      er-bif-list-to-binary
-      (fn
-        (vs)
-        (let
-          ((v (nth vs 0)) (acc (list)) (fail (list false)))
-          (cond
-            (not (or (er-nil? v) (er-cons? v) (er-binary? v)))
-            (raise (er-mk-error-marker (er-mk-atom "badarg")))
-            :else (do
-              (er-iolist-walk! v acc fail)
-              (cond
-                (nth fail 0)
+      (er-binary? v)
+        (for-each
+          (fn (i) (append! acc (nth (get v :bytes) i)))
+          (range 0 (len (get v :bytes))))
+      (= (type-of v) "number")
+        (cond
+          (and (>= v 0) (<= v 255)) (append! acc v)
+          :else (set-nth! fail 0 true))
+      :else (set-nth! fail 0 true))))
+
+(define er-bif-list-to-binary
+  (fn (vs)
+    (let ((v (nth vs 0)) (acc (list)) (fail (list false)))
+      (cond
+        (not (or (er-nil? v) (er-cons? v) (er-binary? v)))
+          (raise (er-mk-error-marker (er-mk-atom "badarg")))
+        :else
+          (do
+            (er-iolist-walk! v acc fail)
+            (cond
+              (nth fail 0)
                 (raise (er-mk-error-marker (er-mk-atom "badarg")))
-                :else (er-mk-binary acc)))))))
+              :else (er-mk-binary acc)))))))
+
     (er-register-bif! "file" "list_dir" 1 er-bif-file-list-dir)
-    (er-register-pure-bif!
-      "erlang"
-      "binary_to_list"
-      1
-      er-bif-binary-to-list)
-    (er-register-pure-bif!
-      "erlang"
-      "list_to_binary"
-      1
-      er-bif-list-to-binary)
+    (er-register-pure-bif! "erlang" "binary_to_list" 1 er-bif-binary-to-list)
+    (er-register-pure-bif! "erlang" "list_to_binary"  1 er-bif-list-to-binary)
     (er-mk-atom "ok")))
 
-(er-register-bif! "http" "listen" 2 er-bif-http-listen)
-
+;; Register everything at load time.
 (er-register-builtin-bifs!)

lib/feed/acl.sx

@@ -0,0 +1,38 @@
+; feed/acl — per-viewer visibility filtering. The same candidate stream yields
+; different timelines for different viewers, so ACL is applied per request and
+; pre-ACL timelines are never cached.
+;
+; permit? is injected: (permit? viewer activity) -> bool. Wire a real acl-sx
+; predicate here; feed/permit-acl? is a self-contained default that reads an
+; optional :visible-to allowlist on the activity.
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx, lib/feed/fanout.sx
+; (feed/-elem?), lib/feed/rank.sx (feed/top).
+
+; default permit: actor always sees own activity; absent/nil :visible-to is
+; public; otherwise viewer must be in the allowlist.
+(define
+  feed/permit-acl?
+  (fn
+    (viewer a)
+    (or
+      (equal? viewer (get a :actor))
+      (let
+        ((allowed (get a :visible-to nil)))
+        (if (= allowed nil) true (feed/-elem? viewer allowed))))))
+
+(define feed/permit-public? (fn (viewer a) true))
+
+; filter a stream to what viewer may read
+(define
+  feed/visible
+  (fn
+    (stream viewer permit?)
+    (feed/filter stream (fn (a) (permit? viewer a)))))
+
+; the capstone: candidate stream -> ACL for viewer -> rank -> top-N
+(define
+  feed/timeline
+  (fn
+    (stream viewer permit? score-fn n)
+    (feed/top (feed/visible stream viewer permit?) score-fn n)))

lib/feed/aggregate.sx

@@ -0,0 +1,62 @@
+; feed/aggregate — group-by / counting via key-reduce. Keys must be strings
+; (dict keys), so composite keys (actor, day) are joined into one string.
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx.
+
+; group activities into a dict: key-string -> (list of activities), order-preserving
+(define
+  feed/group-by
+  (fn
+    (stream key-fn)
+    (reduce
+      (fn
+        (g a)
+        (let
+          ((k (key-fn a)))
+          (assoc g k (append (get g k (list)) (list a)))))
+      {}
+      (feed/items stream))))
+
+; key-string -> count
+(define
+  feed/group-count
+  (fn
+    (stream key-fn)
+    (reduce
+      (fn
+        (g a)
+        (let
+          ((k (key-fn a)))
+          (assoc g k (+ (get g k 0) 1))))
+      {}
+      (feed/items stream))))
+
+; --- composite keys ---------------------------------------------------------
+
+(define feed/day (fn (at window) (floor (/ at window))))
+
+; (actor, day-bucket) -> "actor#day"
+(define
+  feed/actor-day-key
+  (fn
+    (window)
+    (fn
+      (a)
+      (string-append
+        (get a :actor)
+        "#"
+        (number->string (feed/day (get a :at) window))))))
+
+(define
+  feed/by-actor-day
+  (fn (stream window) (feed/group-count stream (feed/actor-day-key window))))
+
+; per-actor activity counts
+(define
+  feed/actor-counts
+  (fn (stream) (feed/group-count stream feed/actor)))
+
+; per-object activity counts (engagement)
+(define
+  feed/object-counts
+  (fn (stream) (feed/group-count stream feed/object)))

lib/feed/api.sx

@@ -0,0 +1,24 @@
+; feed/api — ergonomic API over the stream layer for non-APL callers.
+; A single mutable activity log; post appends, all returns it as a stream.
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx (loaded by harness).
+
+(define feed/-log (list))
+
+; post — normalize then append. Returns the stored activity.
+(define
+  feed/post
+  (fn
+    (raw)
+    (let
+      ((a (feed/normalize raw)))
+      (begin (set! feed/-log (append feed/-log (list a))) a))))
+
+; all — the whole log as a stream (insertion order)
+(define feed/all (fn () (feed/stream feed/-log)))
+
+; reset! — clear the log (test hygiene)
+(define feed/reset! (fn () (begin (set! feed/-log (list)) nil)))
+
+; size — number of posted activities
+(define feed/size (fn () (len feed/-log)))

lib/feed/conformance.sh

@@ -0,0 +1,125 @@
+#!/usr/bin/env bash
+# lib/feed/conformance.sh — run feed test suites, emit scoreboard.json + scoreboard.md.
+
+set -uo pipefail
+cd "$(git rev-parse --show-toplevel)"
+
+SX_SERVER="${SX_SERVER:-/root/rose-ash/hosts/ocaml/_build/default/bin/sx_server.exe}"
+if [ ! -x "$SX_SERVER" ]; then
+  SX_SERVER="hosts/ocaml/_build/default/bin/sx_server.exe"
+fi
+if [ ! -x "$SX_SERVER" ]; then
+  echo "ERROR: sx_server.exe not found." >&2
+  exit 1
+fi
+
+SUITES=(basic fanout rank integration content notify home dedupe trending mute page thread)
+
+OUT_JSON="lib/feed/scoreboard.json"
+OUT_MD="lib/feed/scoreboard.md"
+
+run_suite() {
+  local suite=$1
+  local file="lib/feed/tests/${suite}.sx"
+  local TMP
+  TMP=$(mktemp)
+  cat > "$TMP" << EPOCHS
+(epoch 1)
+(load "spec/stdlib.sx")
+(load "lib/r7rs.sx")
+(load "lib/apl/runtime.sx")
+(load "lib/feed/normalize.sx")
+(load "lib/feed/stream.sx")
+(load "lib/feed/api.sx")
+(load "lib/feed/fanout.sx")
+(load "lib/feed/dedupe.sx")
+(load "lib/feed/aggregate.sx")
+(load "lib/feed/rank.sx")
+(load "lib/feed/acl.sx")
+(load "lib/feed/fed.sx")
+(load "lib/feed/content.sx")
+(load "lib/feed/notify.sx")
+(load "lib/feed/home.sx")
+(load "lib/feed/trending.sx")
+(load "lib/feed/mute.sx")
+(load "lib/feed/page.sx")
+(load "lib/feed/thread.sx")
+(epoch 2)
+(eval "(define feed-test-pass 0)")
+(eval "(define feed-test-fail 0)")
+(eval "(define feed-test (fn (name got expected) (if (= got expected) (set! feed-test-pass (+ feed-test-pass 1)) (set! feed-test-fail (+ feed-test-fail 1)))))")
+(epoch 3)
+(load "${file}")
+(epoch 4)
+(eval "(list feed-test-pass feed-test-fail)")
+EPOCHS
+
+  local OUTPUT
+  OUTPUT=$(timeout 300 "$SX_SERVER" < "$TMP" 2>/dev/null)
+  rm -f "$TMP"
+
+  local LINE
+  LINE=$(echo "$OUTPUT" | awk '/^\(ok-len 4 / {getline; print; exit}')
+  if [ -z "$LINE" ]; then
+    LINE=$(echo "$OUTPUT" | grep -E '^\(ok 4 \([0-9]+ [0-9]+\)\)' | tail -1 \
+            | sed -E 's/^\(ok 4 //; s/\)$//')
+  fi
+
+  local P F
+  P=$(echo "$LINE" | sed -E 's/^\(([0-9]+) ([0-9]+)\).*/\1/')
+  F=$(echo "$LINE" | sed -E 's/^\(([0-9]+) ([0-9]+)\).*/\2/')
+  P=${P:-0}
+  F=${F:-0}
+  echo "${P} ${F}"
+}
+
+declare -A SUITE_PASS
+declare -A SUITE_FAIL
+TOTAL_PASS=0
+TOTAL_FAIL=0
+
+echo "Running feed conformance suite..." >&2
+for s in "${SUITES[@]}"; do
+  read -r p f < <(run_suite "$s")
+  SUITE_PASS[$s]=$p
+  SUITE_FAIL[$s]=$f
+  TOTAL_PASS=$((TOTAL_PASS + p))
+  TOTAL_FAIL=$((TOTAL_FAIL + f))
+  printf "  %-12s %d/%d\n" "$s" "$p" "$((p+f))" >&2
+done
+
+# scoreboard.json
+{
+  printf '{\n'
+  printf '  "suites": {\n'
+  first=1
+  for s in "${SUITES[@]}"; do
+    if [ $first -eq 0 ]; then printf ',\n'; fi
+    printf '    "%s": {"pass": %d, "fail": %d}' "$s" "${SUITE_PASS[$s]}" "${SUITE_FAIL[$s]}"
+    first=0
+  done
+  printf '\n  },\n'
+  printf '  "total_pass": %d,\n' "$TOTAL_PASS"
+  printf '  "total_fail": %d,\n' "$TOTAL_FAIL"
+  printf '  "total": %d\n' "$((TOTAL_PASS + TOTAL_FAIL))"
+  printf '}\n'
+} > "$OUT_JSON"
+
+# scoreboard.md
+{
+  printf '# feed Conformance Scoreboard\n\n'
+  printf '_Generated by `lib/feed/conformance.sh`_\n\n'
+  printf '| Suite | Pass | Fail | Total |\n'
+  printf '|-------|-----:|-----:|------:|\n'
+  for s in "${SUITES[@]}"; do
+    p=${SUITE_PASS[$s]}
+    f=${SUITE_FAIL[$s]}
+    printf '| %s | %d | %d | %d |\n' "$s" "$p" "$f" "$((p+f))"
+  done
+  printf '| **Total** | **%d** | **%d** | **%d** |\n' "$TOTAL_PASS" "$TOTAL_FAIL" "$((TOTAL_PASS + TOTAL_FAIL))"
+} > "$OUT_MD"
+
+echo "Wrote $OUT_JSON and $OUT_MD" >&2
+echo "Total: $TOTAL_PASS pass, $TOTAL_FAIL fail" >&2
+
+[ "$TOTAL_FAIL" -eq 0 ]

lib/feed/content.sx

@@ -0,0 +1,68 @@
+; feed/content — TF-IDF relevance over activity :tags. Rare tags carry more
+; signal, so an activity matching an uncommon tag ranks above one matching a
+; common tag. Composes with rank.sx: feed/tfidf-score is just another scorer.
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx, lib/feed/fanout.sx
+; (feed/-distinct), lib/feed/rank.sx (feed/rank).
+
+; document frequency: tag -> number of activities whose :tags contain it
+; (a tag repeated within one activity counts once toward df)
+(define
+  feed/tag-df
+  (fn
+    (stream)
+    (reduce
+      (fn
+        (df a)
+        (reduce
+          (fn (d t) (assoc d t (+ (get d t 0) 1)))
+          df
+          (feed/-distinct (get a :tags))))
+      {}
+      (feed/items stream))))
+
+; inverse document frequency: tag -> log(N / df)
+(define
+  feed/tag-idf
+  (fn
+    (stream)
+    (let
+      ((n (feed/count stream)) (df (feed/tag-df stream)))
+      (reduce
+        (fn (idf t) (assoc idf t (log (/ n (get df t)))))
+        {}
+        (keys df)))))
+
+; term frequency within one activity: tag -> occurrence count
+(define
+  feed/-tf
+  (fn
+    (a)
+    (reduce
+      (fn (tf t) (assoc tf t (+ (get tf t 0) 1)))
+      {}
+      (get a :tags))))
+
+; relevance of an activity to a query (list of tags) given precomputed idf:
+; sum over query tags of tf(tag in activity) * idf(tag in corpus)
+(define
+  feed/tfidf-score
+  (fn
+    (idf query)
+    (fn
+      (a)
+      (let
+        ((tf (feed/-tf a)))
+        (reduce
+          (fn
+            (acc t)
+            (+ acc (* (get tf t 0) (get idf t 0))))
+          0
+          query)))))
+
+; rank a stream by relevance to query tags (idf computed over the stream itself)
+(define
+  feed/by-relevance
+  (fn
+    (stream query)
+    (feed/rank stream (feed/tfidf-score (feed/tag-idf stream) query))))

lib/feed/dedupe.sx

@@ -0,0 +1,76 @@
+; feed/dedupe — collapse duplicate items, keeping first occurrence per key.
+; Each verb may want its own key (see briefing): "alice posted X" keys on
+; (actor verb object) — distinct per actor; "alice liked X / bob liked X"
+; collapse on (verb object) so the cross-actor likes fold into one.
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx, lib/feed/fanout.sx
+; (feed/-elem? lives in fanout.sx).
+
+; generic: dedupe a stream by key-fn, first occurrence wins (stable)
+(define
+  feed/-dedup-by
+  (fn
+    (items key-fn)
+    (get
+      (reduce
+        (fn
+          (st x)
+          (let
+            ((k (key-fn x)))
+            (if (feed/-elem? k (get st :seen)) st {:seen (append (get st :seen) (list k)) :out (append (get st :out) (list x))})))
+        {:seen (list) :out (list)}
+        items)
+      :out)))
+
+(define
+  feed/dedupe
+  (fn
+    (stream key-fn)
+    (feed/stream (feed/-dedup-by (feed/items stream) key-fn))))
+
+; --- keys -------------------------------------------------------------------
+
+(define
+  feed/activity-key
+  (fn (a) (list (get a :actor) (get a :verb) (get a :object))))
+
+; collapse cross-actor duplicates of the same verb+object (e.g. likes)
+(define feed/collapse-key (fn (a) (list (get a :verb) (get a :object))))
+
+; per-receiver inbox key — one inbox event per (receiver, actor, verb, object)
+(define
+  feed/event-key
+  (fn
+    (ev)
+    (let
+      ((a (get ev :activity)))
+      (list (get ev :to) (get a :actor) (get a :verb) (get a :object)))))
+
+; verbs whose duplicates collapse across actors (reactions, not authorship).
+; rebindable: callers can (set! feed/collapse-verbs ...) to tune the policy.
+(define
+  feed/collapse-verbs
+  (list "like" "favourite" "follow" "boost" "repost"))
+
+; per-verb key: collapse-verbs fold on (verb object); the rest key on
+; (actor verb object).
+(define
+  feed/smart-key
+  (fn
+    (a)
+    (if
+      (feed/-elem? (get a :verb) feed/collapse-verbs)
+      (feed/collapse-key a)
+      (feed/activity-key a))))
+
+; --- ready-made dedupers ----------------------------------------------------
+
+(define feed/dedupe-activities (fn (s) (feed/dedupe s feed/activity-key)))
+
+(define feed/dedupe-collapse (fn (s) (feed/dedupe s feed/collapse-key)))
+
+; verb-aware: reactions collapse cross-actor, posts stay distinct per actor
+(define feed/dedupe-smart (fn (s) (feed/dedupe s feed/smart-key)))
+
+; dedupe an inbox: at most one event per receiver per (actor verb object)
+(define feed/dedupe-inbox (fn (inbox) (feed/dedupe inbox feed/event-key)))

lib/feed/fanout.sx

@@ -0,0 +1,114 @@
+; feed/fanout — THE SHOWCASE. Fan activities out to followers via the APL outer
+; product (∘.×). activities ∘.× audience → an (activity × follower) matrix of
+; inbox events; flatten to a vector; guard-keep only real follow edges.
+;
+; Requires: lib/apl/runtime.sx, lib/feed/normalize.sx, lib/feed/stream.sx.
+;
+; NOTE: apl-outer's combiner result is run through (if (scalar? r) (disclose r) r).
+; A bare dict counts as a scalar (shape ()) and disclose nils it — so the combiner
+; must (enclose ...) its event dict; apl-outer then discloses it back intact.
+
+; --- graph: {followee -> (list of followers)} -------------------------------
+
+(define feed/followers (fn (graph user) (get graph user (list))))
+
+; build a graph from (follower followee) edges: "follower follows followee"
+(define
+  feed/follow-graph
+  (fn
+    (edges)
+    (reduce
+      (fn
+        (g e)
+        (let
+          ((follower (first e)) (followee (nth e 1)))
+          (assoc
+            g
+            followee
+            (append (feed/followers g followee) (list follower)))))
+      {}
+      edges)))
+
+; --- helpers ----------------------------------------------------------------
+
+; unwrap an apl-scalar (has :ravel) back to its value; pass activities through
+(define
+  feed/-val
+  (fn
+    (x)
+    (if (and (= (type-of x) "dict") (has-key? x :ravel)) (disclose x) x)))
+
+(define feed/-elem? (fn (x lst) (some (fn (y) (equal? x y)) lst)))
+
+(define
+  feed/-distinct
+  (fn
+    (lst)
+    (if
+      (= (len lst) 0)
+      (list)
+      (get (apl-unique (make-array (list (len lst)) lst)) :ravel))))
+
+; rank-2 matrix -> rank-1 stream of its ravel
+(define feed/-flatten (fn (arr) (feed/stream (get arr :ravel))))
+
+; distinct receivers across the whole graph, sorted for determinism
+; (dict key order is unspecified, so sort to pin audience/recipient ordering)
+(define
+  feed/audience
+  (fn
+    (graph)
+    (sort
+      (feed/-distinct
+        (reduce
+          (fn (acc k) (append acc (feed/followers graph k)))
+          (list)
+          (keys graph))))))
+
+; --- the outer product ------------------------------------------------------
+
+; one (activity, follower) inbox event, enclosed so apl-outer keeps the dict
+(define feed/-mk-event (fn (a f) (enclose {:activity (feed/-val a) :to (feed/-val f)})))
+
+; keep events where :to actually follows the activity's actor
+(define
+  feed/-edge?
+  (fn
+    (graph)
+    (fn
+      (ev)
+      (feed/-elem?
+        (get ev :to)
+        (feed/followers graph (get (get ev :activity) :actor))))))
+
+; fanout — activities ∘.× audience, flatten, guard-keep real edges
+(define
+  feed/fanout
+  (fn
+    (stream graph)
+    (let
+      ((matrix (apl-outer feed/-mk-event stream (feed/stream (feed/audience graph)))))
+      (feed/filter (feed/-flatten matrix) (feed/-edge? graph)))))
+
+; --- inbox queries ----------------------------------------------------------
+
+(define
+  feed/inbox-for
+  (fn
+    (inbox user)
+    (feed/filter inbox (fn (ev) (equal? (get ev :to) user)))))
+
+(define
+  feed/recipients
+  (fn
+    (inbox)
+    (feed/-distinct (map (fn (ev) (get ev :to)) (feed/items inbox)))))
+
+; the activities (unwrapped) destined for a user
+(define
+  feed/inbox-activities
+  (fn
+    (inbox user)
+    (map
+      (fn (ev) (get ev :activity))
+      (feed/items (feed/inbox-for inbox user)))))

lib/feed/fed.sx

@@ -0,0 +1,60 @@
+; feed/fed — federation. Outbound: a local post fans out, then splits into local
+; vs remote inboxes; remote events are handed to an injected send-fn. Inbound:
+; peer activities merge into the local stream, deduped. Backfill: pull peer
+; history via an injected fetch-fn and merge.
+;
+; remote? / send-fn / fetch-fn are injected so real fed-sx transport wires in here
+; without feed depending on it.
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx, lib/feed/fanout.sx,
+; lib/feed/dedupe.sx.
+
+; --- merge / ingest ---------------------------------------------------------
+
+(define
+  feed/merge
+  (fn (s1 s2) (feed/stream (append (feed/items s1) (feed/items s2)))))
+
+; merge a peer stream into local, dropping (actor verb object) duplicates
+(define
+  feed/ingest
+  (fn (local peer) (feed/dedupe-activities (feed/merge local peer))))
+
+; --- inbound ----------------------------------------------------------------
+
+; peer pushes raw activities to the local inbox; normalize + ingest
+(define
+  feed/inbound
+  (fn
+    (local raw-activities)
+    (feed/ingest local (feed/stream (map feed/normalize raw-activities)))))
+
+; backfill on subscribe: pull peer history via fetch-fn, normalize, ingest
+(define
+  feed/backfill
+  (fn (local fetch-fn peer-id) (feed/inbound local (fetch-fn peer-id))))
+
+; --- outbound ---------------------------------------------------------------
+
+; split an inbox into local vs remote deliveries by viewer-id predicate
+(define feed/partition-inbox (fn (inbox remote?) {:local (feed/filter inbox (fn (ev) (not (remote? (get ev :to))))) :remote (feed/filter inbox (fn (ev) (remote? (get ev :to))))}))
+
+; fan a stream out over the graph, then partition by locality
+(define
+  feed/federate
+  (fn
+    (stream graph remote?)
+    (feed/partition-inbox (feed/fanout stream graph) remote?)))
+
+; deliver: hand each remote event to send-fn, return the local inbox to enqueue
+(define
+  feed/deliver
+  (fn
+    (stream graph remote? send-fn)
+    (let
+      ((parts (feed/federate stream graph remote?)))
+      (begin
+        (for-each
+          (fn (ev) (send-fn (get ev :to) (get ev :activity)))
+          (feed/items (get parts :remote)))
+        (get parts :local)))))

lib/feed/home.sx

@@ -0,0 +1,23 @@
+; feed/home — the capstone. A user's home timeline is the whole pipeline as one
+; line: fan all activities out over the follow graph, take the events landing in
+; the viewer's inbox, dedupe cross-posts, apply the viewer's ACL, rank, take N.
+;
+; Requires: fanout.sx, dedupe.sx, acl.sx (feed/timeline), rank.sx, stream.sx.
+
+; the activities in a user's inbox, as a stream
+(define
+  feed/inbox-stream
+  (fn (inbox user) (feed/stream (feed/inbox-activities inbox user))))
+
+; fanout ∘ inbox ∘ dedupe ∘ ACL ∘ rank ∘ take
+(define
+  feed/home
+  (fn
+    (stream graph viewer permit? score-fn n)
+    (feed/timeline
+      (feed/dedupe-activities
+        (feed/inbox-stream (feed/fanout stream graph) viewer))
+      viewer
+      permit?
+      score-fn
+      n)))

lib/feed/mute.sx

@@ -0,0 +1,44 @@
+; feed/mute — viewer-controlled filtering. ACL (acl.sx) is author-controlled
+; visibility; mute is the reader's own preference: hide muted actors or tags.
+; Like ACL it is per-viewer and applied per request, never cached.
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx, lib/feed/fanout.sx
+; (feed/-elem?).
+
+; drop activities authored by a muted actor
+(define
+  feed/mute-actors
+  (fn
+    (stream actors)
+    (feed/filter
+      stream
+      (fn (a) (not (feed/-elem? (get a :actor) actors))))))
+
+; drop activities carrying any muted tag
+(define
+  feed/mute-tags
+  (fn
+    (stream tags)
+    (feed/filter
+      stream
+      (fn (a) (not (some (fn (t) (feed/-elem? t tags)) (get a :tags)))))))
+
+; drop activities about a muted object (thread mute)
+(define
+  feed/mute-objects
+  (fn
+    (stream objects)
+    (feed/filter
+      stream
+      (fn (a) (not (feed/-elem? (get a :object) objects))))))
+
+; apply a viewer preference bag: {:mute-actors (...) :mute-tags (...) :mute-objects (...)}
+(define
+  feed/apply-prefs
+  (fn
+    (stream prefs)
+    (feed/mute-objects
+      (feed/mute-tags
+        (feed/mute-actors stream (get prefs :mute-actors (list)))
+        (get prefs :mute-tags (list)))
+      (get prefs :mute-objects (list)))))

lib/feed/normalize.sx

@@ -0,0 +1,31 @@
+; feed/normalize — coerce arbitrary input into the canonical activity record.
+; An activity is a small dict {:actor :verb :object :at :tags}; a stream is an
+; APL vector of such dicts (see stream.sx). Extra keys on the raw input survive
+; (e.g. :visible-to for ACL, peer metadata for federation) — :tags is the
+; flexible bag but the record is not closed.
+
+(define feed/activity-keys (list :actor :verb :object :at :tags))
+
+(define
+  feed/normalize
+  (fn
+    (raw)
+    (let
+      ((d (if (= (type-of raw) "dict") raw {})))
+      (merge d {:actor (get d :actor "") :object (get d :object nil) :at (get d :at 0) :tags (let ((t (get d :tags (list)))) (if (list? t) t (list t))) :verb (get d :verb "post")}))))
+
+(define
+  feed/activity
+  (fn (actor verb object at tags) (feed/normalize {:actor actor :object object :at at :tags tags :verb verb})))
+
+(define feed/actor (fn (a) (get a :actor)))
+(define feed/verb (fn (a) (get a :verb)))
+(define feed/object (fn (a) (get a :object)))
+(define feed/at (fn (a) (get a :at)))
+(define feed/tags (fn (a) (get a :tags)))
+
+(define
+  feed/activity?
+  (fn
+    (a)
+    (and (= (type-of a) "dict") (has-key? a :actor) (has-key? a :verb))))

lib/feed/notify.sx

@@ -0,0 +1,45 @@
+; feed/notify — a notification feed is a thin layer over a recipient's inbox:
+; the events directed at a user, optionally verb-filtered, and a digest that
+; collapses "alice, bob and 1 other liked X" by (verb, object).
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx, lib/feed/fanout.sx
+; (feed/inbox-for, feed/-elem?).
+
+; all inbox events for a user (their raw notifications)
+(define feed/notifications (fn (inbox user) (feed/inbox-for inbox user)))
+
+; restrict to notification-worthy verbs (e.g. (list "like" "reply" "follow"))
+(define
+  feed/notify-verbs
+  (fn
+    (inbox user verbs)
+    (feed/filter
+      (feed/inbox-for inbox user)
+      (fn (ev) (feed/-elem? (get (get ev :activity) :verb) verbs)))))
+
+; group key "verb|object" — deterministic, sortable
+(define
+  feed/-notify-key
+  (fn
+    (ev)
+    (let
+      ((a (get ev :activity)))
+      (string-append (get a :verb) "|" (get a :object)))))
+
+; digest: one entry per (verb, object) with the distinct actors and a count,
+; ordered by key for determinism.
+(define
+  feed/notify-digest
+  (fn
+    (inbox user)
+    (let
+      ((events (feed/items (feed/inbox-for inbox user))))
+      (let
+        ((groups (reduce (fn (g ev) (let ((a (get ev :activity)) (k (feed/-notify-key ev))) (let ((cur (get g k {:object (get a :object) :actors (list) :verb (get a :verb)}))) (assoc g k (assoc cur :actors (append (get cur :actors) (list (get a :actor)))))))) {} events)))
+        (map
+          (fn
+            (k)
+            (let
+              ((grp (get groups k)))
+              (assoc grp :count (len (get grp :actors)))))
+          (sort (keys groups)))))))

lib/feed/page.sx

@@ -0,0 +1,50 @@
+; feed/page — pagination. Offset/limit for indexed access, and cursor-based
+; (by :at) for recency feeds, which is stable under inserts: a cursor is the
+; :at of the last item seen, and the next page is the newest items older than it.
+;
+; Requires: lib/feed/stream.sx (feed/recent, feed/take, feed/filter).
+
+; --- offset / limit ---------------------------------------------------------
+
+(define
+  feed/page
+  (fn
+    (stream offset limit)
+    (feed/stream (take (drop (feed/items stream) offset) limit))))
+
+(define
+  feed/page-count
+  (fn (stream limit) (ceil (/ (feed/count stream) limit))))
+
+; --- cursor (recency feeds) -------------------------------------------------
+
+; activities strictly older than cursor (scroll down / load older)
+(define
+  feed/before
+  (fn
+    (stream cursor)
+    (feed/filter stream (fn (a) (< (get a :at) cursor)))))
+
+; activities strictly newer than cursor (load newer / "N new posts")
+(define
+  feed/after
+  (fn
+    (stream cursor)
+    (feed/filter stream (fn (a) (> (get a :at) cursor)))))
+
+; one page: the `limit` newest activities older than cursor, newest first
+(define
+  feed/page-before
+  (fn
+    (stream cursor limit)
+    (feed/take (feed/recent (feed/before stream cursor)) limit)))
+
+; cursor to fetch the next (older) page: :at of the last item of a page,
+; or nil when the page is empty (end of feed)
+(define
+  feed/next-cursor
+  (fn
+    (page)
+    (let
+      ((items (feed/items page)))
+      (if (= (len items) 0) nil (get (last items) :at)))))

lib/feed/rank.sx

@@ -0,0 +1,92 @@
+; feed/rank — scoring + ranking. Scorers are (activity -> number). Ranking is a
+; stable two-pass grade-down: first by :at descending (the tiebreak), then by
+; score descending — so ties resolve by recency, then by input order. Fully
+; deterministic on ties.
+;
+; Requires: lib/apl/runtime.sx, lib/feed/normalize.sx, lib/feed/stream.sx.
+
+; --- scorers ----------------------------------------------------------------
+
+; recency: half-life decay. score = 0.5 ^ (age / half-life). at==now -> 1.0.
+(define
+  feed/recency
+  (fn
+    (now half-life)
+    (fn (a) (expt 0.5 (/ (- now (get a :at)) half-life)))))
+
+; velocity: how many of this actor's activities fall in (at-window, at] —
+; a burst of recent activity scores higher.
+(define
+  feed/velocity
+  (fn
+    (stream window)
+    (fn
+      (a)
+      (len
+        (filter
+          (fn
+            (b)
+            (and
+              (equal? (get b :actor) (get a :actor))
+              (<= (get b :at) (get a :at))
+              (> (get b :at) (- (get a :at) window))))
+          (feed/items stream))))))
+
+; engagement: how many activities in the stream touch this activity's :object
+(define
+  feed/engagement
+  (fn
+    (stream)
+    (fn
+      (a)
+      (len
+        (filter
+          (fn (b) (equal? (get b :object) (get a :object)))
+          (feed/items stream))))))
+
+; composite: weighted sum. parts = (list (list weight scorer) ...)
+(define
+  feed/composite
+  (fn
+    (parts)
+    (fn
+      (a)
+      (reduce
+        (fn (acc p) (+ acc (* (first p) ((nth p 1) a))))
+        0
+        parts))))
+
+; --- ranking ----------------------------------------------------------------
+
+; stable reorder of items by key-fn, descending (grade-down is stable)
+(define
+  feed/-desc-by
+  (fn
+    (items key-fn)
+    (let
+      ((keys (make-array (list (len items)) (map key-fn items))))
+      (let
+        ((order (get (apl-grade-down keys) :ravel)))
+        (map (fn (i) (nth items (- i 1))) order)))))
+
+; rank by score descending; ties -> :at descending -> input order
+(define
+  feed/rank
+  (fn
+    (stream score-fn)
+    (let
+      ((by-at (feed/-desc-by (feed/items stream) feed/at)))
+      (feed/stream (feed/-desc-by by-at score-fn)))))
+
+; attach a :score to each activity (for inspection / debugging)
+(define
+  feed/with-scores
+  (fn
+    (stream score-fn)
+    (feed/stream
+      (map (fn (a) (assoc a :score (score-fn a))) (feed/items stream)))))
+
+; top-N ranked timeline
+(define
+  feed/top
+  (fn (stream score-fn n) (feed/take (feed/rank stream score-fn) n)))

lib/feed/scoreboard.json

@@ -0,0 +1,19 @@
+{
+  "suites": {
+    "basic": {"pass": 30, "fail": 0},
+    "fanout": {"pass": 29, "fail": 0},
+    "rank": {"pass": 24, "fail": 0},
+    "integration": {"pass": 22, "fail": 0},
+    "content": {"pass": 15, "fail": 0},
+    "notify": {"pass": 8, "fail": 0},
+    "home": {"pass": 6, "fail": 0},
+    "dedupe": {"pass": 9, "fail": 0},
+    "trending": {"pass": 11, "fail": 0},
+    "mute": {"pass": 9, "fail": 0},
+    "page": {"pass": 14, "fail": 0},
+    "thread": {"pass": 12, "fail": 0}
+  },
+  "total_pass": 189,
+  "total_fail": 0,
+  "total": 189
+}

lib/feed/scoreboard.md

@@ -0,0 +1,19 @@
+# feed Conformance Scoreboard
+
+_Generated by `lib/feed/conformance.sh`_
+
+| Suite | Pass | Fail | Total |
+|-------|-----:|-----:|------:|
+| basic | 30 | 0 | 30 |
+| fanout | 29 | 0 | 29 |
+| rank | 24 | 0 | 24 |
+| integration | 22 | 0 | 22 |
+| content | 15 | 0 | 15 |
+| notify | 8 | 0 | 8 |
+| home | 6 | 0 | 6 |
+| dedupe | 9 | 0 | 9 |
+| trending | 11 | 0 | 11 |
+| mute | 9 | 0 | 9 |
+| page | 14 | 0 | 14 |
+| thread | 12 | 0 | 12 |
+| **Total** | **189** | **0** | **189** |

lib/feed/stream.sx

@@ -0,0 +1,75 @@
+; feed/stream — a stream is an APL vector (rank-1 array) whose ravel holds
+; activity dicts. Operations lift APL primitives onto this shape: filter via
+; compress (/), sort via grade (⍋), take via ↑, reverse via ⌽.
+;
+; Requires: lib/apl/runtime.sx, lib/feed/normalize.sx (loaded by harness).
+
+(define feed/stream (fn (acts) (make-array (list (len acts)) acts)))
+
+(define feed/items (fn (s) (get s :ravel)))
+
+(define feed/count (fn (s) (len (get s :ravel))))
+
+(define feed/empty (feed/stream (list)))
+
+(define feed/empty? (fn (s) (= (feed/count s) 0)))
+
+; filter — bool mask ∘ compress. pred : activity -> truthy
+(define
+  feed/filter
+  (fn
+    (s pred)
+    (let
+      ((items (get s :ravel)))
+      (let
+        ((mask (make-array (list (len items)) (map (fn (a) (if (pred a) 1 0)) items))))
+        (apl-compress mask s)))))
+
+; sort-by — ascending, stable on ties (grade-up is stable). key-fn : activity -> number
+(define
+  feed/sort-by
+  (fn
+    (s key-fn)
+    (let
+      ((items (get s :ravel)))
+      (let
+        ((keys (make-array (list (len items)) (map key-fn items))))
+        (let
+          ((order (get (apl-grade-up keys) :ravel)))
+          (feed/stream (map (fn (i) (nth items (- i 1))) order)))))))
+
+(define feed/sort-by-at (fn (s) (feed/sort-by s feed/at)))
+
+; newest-first: ascending sort then reverse (⌽)
+(define feed/recent (fn (s) (apl-reverse (feed/sort-by-at s))))
+
+; take N (↑), clamped to stream length so it never over-takes/pads
+(define
+  feed/take
+  (fn
+    (s n)
+    (let
+      ((c (feed/count s)))
+      (if (>= n c) s (apl-take (apl-scalar n) s)))))
+
+(define feed/reverse (fn (s) (apl-reverse s)))
+
+; common predicates
+(define
+  feed/by-actor
+  (fn (s actor) (feed/filter s (fn (a) (equal? (get a :actor) actor)))))
+
+(define
+  feed/by-verb
+  (fn (s verb) (feed/filter s (fn (a) (equal? (get a :verb) verb)))))
+
+(define
+  feed/by-object
+  (fn
+    (s object)
+    (feed/filter s (fn (a) (equal? (get a :object) object)))))
+
+; activities at or after timestamp t
+(define
+  feed/since
+  (fn (s t) (feed/filter s (fn (a) (>= (get a :at) t)))))

lib/feed/tests/basic.sx

@@ -0,0 +1,118 @@
+; Phase 1 — normalize, stream ops, api. Uses the feed-test harness
+; (feed-test name got expected) provided by conformance.sh.
+
+; ---------- normalize ----------
+
+(feed-test
+  "normalize default actor"
+  (feed/actor (feed/normalize {}))
+  "")
+(feed-test
+  "normalize default verb"
+  (feed/verb (feed/normalize {}))
+  "post")
+(feed-test
+  "normalize default at"
+  (feed/at (feed/normalize {}))
+  0)
+(feed-test
+  "normalize default object"
+  (feed/object (feed/normalize {}))
+  nil)
+(feed-test
+  "normalize default tags"
+  (feed/tags (feed/normalize {}))
+  (list))
+(feed-test
+  "normalize keeps actor"
+  (feed/actor (feed/normalize {:actor "alice"}))
+  "alice")
+(feed-test
+  "normalize keeps verb"
+  (feed/verb (feed/normalize {:verb "like"}))
+  "like")
+(feed-test
+  "normalize scalar tag -> list"
+  (feed/tags (feed/normalize {:tags "x"}))
+  (list "x"))
+(feed-test
+  "normalize list tags kept"
+  (feed/tags (feed/normalize {:tags (list "a" "b")}))
+  (list "a" "b"))
+(feed-test
+  "activity constructor at"
+  (feed/at (feed/activity "a" "post" "o" 5 (list)))
+  5)
+(feed-test
+  "activity? on activity"
+  (feed/activity? (feed/normalize {:actor "a"}))
+  true)
+(feed-test "activity? on number" (feed/activity? 5) false)
+(feed-test "activity? on bare dict" (feed/activity? {:foo 1}) false)
+
+; ---------- stream ----------
+
+(define
+  S
+  (feed/stream
+    (list
+      (feed/activity "alice" "post" "p1" 30 (list))
+      (feed/activity "bob" "like" "p1" 10 (list))
+      (feed/activity "alice" "post" "p2" 20 (list)))))
+
+(feed-test "stream count" (feed/count S) 3)
+(feed-test "stream items len" (len (feed/items S)) 3)
+(feed-test
+  "sort-by-at actors asc"
+  (map feed/actor (feed/items (feed/sort-by-at S)))
+  (list "bob" "alice" "alice"))
+(feed-test
+  "recent newest first"
+  (map feed/at (feed/items (feed/recent S)))
+  (list 30 20 10))
+(feed-test
+  "take 2 of recent"
+  (feed/count (feed/take (feed/recent S) 2))
+  2)
+(feed-test
+  "take clamps past end"
+  (feed/count (feed/take S 10))
+  3)
+(feed-test
+  "by-actor alice count"
+  (feed/count (feed/by-actor S "alice"))
+  2)
+(feed-test
+  "by-verb like actor"
+  (map feed/actor (feed/items (feed/by-verb S "like")))
+  (list "bob"))
+(feed-test
+  "by-object p1 count"
+  (feed/count (feed/by-object S "p1"))
+  2)
+(feed-test
+  "since 20 count"
+  (feed/count (feed/since S 20))
+  2)
+(feed-test
+  "reverse ats"
+  (map feed/at (feed/items (feed/reverse S)))
+  (list 20 10 30))
+(feed-test "empty? on empty" (feed/empty? feed/empty) true)
+(feed-test
+  "empty? on filtered-out"
+  (feed/empty? (feed/by-actor S "zzz"))
+  true)
+
+; ---------- api ----------
+
+(feed/reset!)
+(feed/post {:actor "x" :at 1 :verb "post"})
+(feed/post {:actor "y" :at 2 :verb "like"})
+(feed-test "api size after posts" (feed/size) 2)
+(feed-test "api all count" (feed/count (feed/all)) 2)
+(feed-test
+  "post returns normalized verb"
+  (feed/verb (feed/post {:actor "z"}))
+  "post")
+(feed-test "api size after third post" (feed/size) 3)

lib/feed/tests/content.sx

@@ -0,0 +1,85 @@
+; Follow-up — TF-IDF content ranking over :tags. (feed-test name got expected)
+
+(define
+  corpus
+  (feed/stream
+    (list
+      (feed/normalize {:actor "u" :object "o1" :at 10 :tags (list "cats" "funny")})
+      (feed/normalize {:actor "u" :object "o2" :at 20 :tags (list "cats" "news")})
+      (feed/normalize {:actor "u" :object "o3" :at 30 :tags (list "politics" "news")})
+      (feed/normalize {:actor "u" :object "o4" :at 40 :tags (list "cats")}))))
+
+; ---------- document frequency ----------
+
+(feed-test "df cats" (get (feed/tag-df corpus) "cats") 3)
+(feed-test "df news" (get (feed/tag-df corpus) "news") 2)
+(feed-test "df funny" (get (feed/tag-df corpus) "funny") 1)
+(feed-test "df politics" (get (feed/tag-df corpus) "politics") 1)
+(feed-test "df full" (feed/tag-df corpus) {:news 2 :funny 1 :politics 1 :cats 3})
+
+; ---------- inverse document frequency ----------
+
+(feed-test
+  "idf news = log(4/2)"
+  (get (feed/tag-idf corpus) "news")
+  (log 2))
+(feed-test
+  "idf funny = log(4/1)"
+  (get (feed/tag-idf corpus) "funny")
+  (log 4))
+(feed-test
+  "rarer tag has higher idf"
+  (>
+    (get (feed/tag-idf corpus) "funny")
+    (get (feed/tag-idf corpus) "cats"))
+  true)
+
+; ---------- tf-idf scoring ----------
+
+(define idf (feed/tag-idf corpus))
+
+(feed-test
+  "score query funny on o1"
+  ((feed/tfidf-score idf (list "funny")) (feed/normalize {:actor "u" :object "x" :tags (list "cats" "funny")}))
+  (log 4))
+(feed-test
+  "score query funny on non-match"
+  ((feed/tfidf-score idf (list "funny")) (feed/normalize {:actor "u" :object "x" :tags (list "cats")}))
+  0)
+(feed-test
+  "unknown query tag scores 0"
+  ((feed/tfidf-score idf (list "zzz")) (feed/normalize {:actor "u" :object "x" :tags (list "cats")}))
+  0)
+
+; ---------- ranking by relevance ----------
+
+; query news: o2,o3 match (score log2), o1,o4 don't (0); ties break by :at desc
+(feed-test
+  "by-relevance news order"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/by-relevance corpus (list "news"))))
+  (list "o3" "o2" "o4" "o1"))
+
+; query funny: only o1 matches -> ranks first
+(feed-test
+  "by-relevance funny first"
+  (get
+    (nth (feed/items (feed/by-relevance corpus (list "funny"))) 0)
+    :object)
+  "o1")
+
+; query (cats news): o2 carries both tags -> highest combined tf-idf
+(feed-test
+  "by-relevance cats+news top"
+  (get
+    (nth
+      (feed/items (feed/by-relevance corpus (list "cats" "news")))
+      0)
+    :object)
+  "o2")
+
+(feed-test
+  "by-relevance preserves count"
+  (feed/count (feed/by-relevance corpus (list "cats")))
+  4)

lib/feed/tests/dedupe.sx

@@ -0,0 +1,56 @@
+; Follow-up — verb-aware (smart) dedupe. (feed-test name got expected)
+
+; reactions (like/follow) collapse cross-actor; posts stay distinct per actor
+(define
+  M
+  (feed/stream
+    (list
+      (feed/activity "alice" "like" "X" 1 (list))
+      (feed/activity "bob" "like" "X" 2 (list))
+      (feed/activity "alice" "post" "P" 3 (list))
+      (feed/activity "bob" "post" "P" 4 (list))
+      (feed/activity "alice" "follow" "C" 5 (list))
+      (feed/activity "bob" "follow" "C" 6 (list))))) ; collapses
+
+(feed-test
+  "smart dedupe total"
+  (feed/count (feed/dedupe-smart M))
+  4)
+(feed-test
+  "smart keeps both posts"
+  (feed/count (feed/by-verb (feed/dedupe-smart M) "post"))
+  2)
+(feed-test
+  "smart collapses likes to one"
+  (feed/count (feed/by-verb (feed/dedupe-smart M) "like"))
+  1)
+(feed-test
+  "smart collapses follows to one"
+  (feed/count (feed/by-verb (feed/dedupe-smart M) "follow"))
+  1)
+(feed-test
+  "collapsed like keeps first actor"
+  (map feed/actor (feed/items (feed/by-verb (feed/dedupe-smart M) "like")))
+  (list "alice"))
+
+; contrast: plain activity dedupe keeps cross-actor likes distinct
+(feed-test
+  "activity dedupe keeps both likes"
+  (feed/count (feed/by-verb (feed/dedupe-activities M) "like"))
+  2)
+
+; contrast: blanket collapse folds the two posts (same verb+object) too
+(feed-test
+  "collapse dedupe folds posts"
+  (feed/count (feed/by-verb (feed/dedupe-collapse M) "post"))
+  1)
+
+; smart-key dispatch
+(feed-test
+  "smart-key reaction -> (verb object)"
+  (feed/smart-key (feed/activity "alice" "like" "X" 0 (list)))
+  (list "like" "X"))
+(feed-test
+  "smart-key post -> (actor verb object)"
+  (feed/smart-key (feed/activity "alice" "post" "P" 0 (list)))
+  (list "alice" "post" "P"))

lib/feed/tests/fanout.sx

@@ -0,0 +1,187 @@
+; Phase 2 — fanout via outer product + dedupe. (feed-test name got expected)
+
+; ---------- graph ----------
+
+; edges: (follower followee). bob,carol follow alice; carol,dave follow bob.
+(define
+  G
+  (feed/follow-graph
+    (list
+      (list "bob" "alice")
+      (list "carol" "alice")
+      (list "carol" "bob")
+      (list "dave" "bob"))))
+
+(feed-test "followers alice" (feed/followers G "alice") (list "bob" "carol"))
+(feed-test "followers bob" (feed/followers G "bob") (list "carol" "dave"))
+(feed-test "followers unknown" (feed/followers G "zzz") (list))
+(feed-test "audience distinct" (feed/audience G) (list "bob" "carol" "dave"))
+
+; ---------- fanout ----------
+
+(define
+  S
+  (feed/stream
+    (list
+      (feed/activity "alice" "post" "p1" 10 (list))
+      (feed/activity "alice" "post" "p2" 20 (list))
+      (feed/activity "bob" "like" "p1" 30 (list)))))
+
+(define IB (feed/fanout S G))
+
+(feed-test "fanout total edges" (feed/count IB) 6)
+(feed-test
+  "inbox bob count"
+  (feed/count (feed/inbox-for IB "bob"))
+  2)
+(feed-test
+  "inbox carol count"
+  (feed/count (feed/inbox-for IB "carol"))
+  3)
+(feed-test
+  "inbox dave count"
+  (feed/count (feed/inbox-for IB "dave"))
+  1)
+(feed-test
+  "inbox alice (follows none)"
+  (feed/count (feed/inbox-for IB "alice"))
+  0)
+(feed-test
+  "recipients order"
+  (feed/recipients IB)
+  (list "bob" "carol" "dave"))
+(feed-test
+  "bob inbox objects"
+  (map (fn (a) (get a :object)) (feed/inbox-activities IB "bob"))
+  (list "p1" "p2"))
+(feed-test
+  "dave inbox objects"
+  (map (fn (a) (get a :object)) (feed/inbox-activities IB "dave"))
+  (list "p1"))
+(feed-test
+  "dave inbox verb"
+  (map (fn (a) (get a :verb)) (feed/inbox-activities IB "dave"))
+  (list "like"))
+
+; empty graph → no audience → no edges
+(feed-test
+  "empty graph fanout"
+  (feed/count (feed/fanout S {}))
+  0)
+
+; actor nobody follows produces no edges
+(define
+  Sghost
+  (feed/stream (list (feed/activity "ghost" "post" "g1" 5 (list)))))
+(feed-test
+  "unfollowed actor fanout"
+  (feed/count (feed/fanout Sghost G))
+  0)
+
+; ---------- high fanout (popular actor) ----------
+
+(define
+  Gstar
+  (feed/follow-graph
+    (list
+      (list "u1" "star")
+      (list "u2" "star")
+      (list "u3" "star")
+      (list "u4" "star")
+      (list "u5" "star"))))
+(define
+  Sstar
+  (feed/stream (list (feed/activity "star" "post" "s1" 1 (list)))))
+(feed-test
+  "star fanout count"
+  (feed/count (feed/fanout Sstar Gstar))
+  5)
+(feed-test "star audience size" (len (feed/audience Gstar)) 5)
+
+; ---------- mutual follow ----------
+
+(define Gmut (feed/follow-graph (list (list "a" "b") (list "b" "a"))))
+(define
+  Smut
+  (feed/stream
+    (list
+      (feed/activity "a" "post" "pa" 1 (list))
+      (feed/activity "b" "post" "pb" 2 (list)))))
+(define IBmut (feed/fanout Smut Gmut))
+(feed-test "mutual total" (feed/count IBmut) 2)
+(feed-test
+  "mutual a gets pb"
+  (map (fn (x) (get x :object)) (feed/inbox-activities IBmut "a"))
+  (list "pb"))
+(feed-test
+  "mutual b gets pa"
+  (map (fn (x) (get x :object)) (feed/inbox-activities IBmut "b"))
+  (list "pa"))
+
+; ---------- dedupe ----------
+
+(define
+  Sdup2
+  (feed/stream
+    (list
+      (feed/activity "alice" "post" "p1" 1 (list))
+      (feed/activity "alice" "post" "p1" 9 (list))
+      (feed/activity "alice" "post" "p2" 2 (list)))))
+(feed-test
+  "dedupe-activities collapses dup"
+  (feed/count (feed/dedupe-activities Sdup2))
+  2)
+(feed-test
+  "dedupe-activities keeps distinct"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/dedupe-activities Sdup2)))
+  (list "p1" "p2"))
+
+(define
+  Slikes
+  (feed/stream
+    (list
+      (feed/activity "alice" "like" "X" 1 (list))
+      (feed/activity "bob" "like" "X" 2 (list))
+      (feed/activity "carol" "like" "Y" 3 (list)))))
+(feed-test
+  "collapse cross-actor likes"
+  (feed/count (feed/dedupe-collapse Slikes))
+  2)
+(feed-test
+  "collapse keeps distinct objects"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/dedupe-collapse Slikes)))
+  (list "X" "Y"))
+
+(feed-test
+  "activity-key shape"
+  (feed/activity-key (feed/activity "a" "post" "o" 0 (list)))
+  (list "a" "post" "o"))
+(feed-test
+  "collapse-key shape"
+  (feed/collapse-key (feed/activity "a" "like" "o" 0 (list)))
+  (list "like" "o"))
+
+; cross-post: alice posts p1 twice → bob's inbox has it twice → dedupe-inbox → once
+(define
+  Scross
+  (feed/stream
+    (list
+      (feed/activity "alice" "post" "p1" 1 (list))
+      (feed/activity "alice" "post" "p1" 5 (list)))))
+(define IBcross (feed/fanout Scross G))
+(feed-test
+  "cross-post raw bob count"
+  (feed/count (feed/inbox-for IBcross "bob"))
+  2)
+(feed-test
+  "cross-post deduped bob count"
+  (feed/count (feed/inbox-for (feed/dedupe-inbox IBcross) "bob"))
+  1)
+(feed-test
+  "dedupe-inbox keeps distinct receivers"
+  (feed/count (feed/dedupe-inbox IBcross))
+  2)

lib/feed/tests/home.sx

@@ -0,0 +1,73 @@
+; Follow-up — feed/home capstone pipeline. (feed-test name got expected)
+
+; alice follows star and bob (edges: follower followee)
+(define
+  G
+  (feed/follow-graph (list (list "alice" "star") (list "alice" "bob"))))
+
+; star posts s1 then s2; bob posts b1; star re-posts s1 (cross-post dup);
+; zoe posts z1 (alice does NOT follow zoe)
+(define
+  S
+  (feed/stream
+    (list
+      (feed/activity "star" "post" "s1" 10 (list))
+      (feed/activity "star" "post" "s2" 20 (list))
+      (feed/activity "bob" "post" "b1" 15 (list))
+      (feed/activity "star" "post" "s1" 5 (list))
+      (feed/activity "zoe" "post" "z1" 30 (list)))))
+
+(define rec (feed/recency 100 10))
+
+(feed-test
+  "home count (deduped, followed only)"
+  (feed/count (feed/home S G "alice" feed/permit-public? rec 10))
+  3)
+
+(feed-test
+  "home order by recency"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/home S G "alice" feed/permit-public? rec 10)))
+  (list "s2" "b1" "s1"))
+
+(feed-test
+  "home excludes unfollowed zoe"
+  (feed/-elem?
+    "z1"
+    (map
+      (fn (a) (get a :object))
+      (feed/items (feed/home S G "alice" feed/permit-public? rec 10))))
+  false)
+
+(feed-test
+  "home top-2"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/home S G "alice" feed/permit-public? rec 2)))
+  (list "s2" "b1"))
+
+(feed-test
+  "home dedupes cross-post (one s1)"
+  (len
+    (filter
+      (fn (o) (equal? o "s1"))
+      (map
+        (fn (a) (get a :object))
+        (feed/items
+          (feed/home S G "alice" feed/permit-public? rec 10)))))
+  1)
+
+; ACL applied per-viewer in the home pipeline
+(define
+  Sacl
+  (feed/stream
+    (list (feed/normalize {:actor "star" :object "pub" :at 20}) (feed/normalize {:actor "star" :object "sec" :visible-to (list "carol") :at 25}))))
+(define Gacl (feed/follow-graph (list (list "alice" "star"))))
+
+(feed-test
+  "home hides activity alice not permitted"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/home Sacl Gacl "alice" feed/permit-acl? rec 10)))
+  (list "pub"))

lib/feed/tests/integration.sx

@@ -0,0 +1,155 @@
+; Phase 4 — visibility (ACL) + federation, and the end-to-end timeline.
+; (feed-test name got expected)
+
+; ---------- ACL visibility ----------
+; pub: public. sec: bob, allows carol. dm: frank, allows dave.
+
+(define
+  C
+  (feed/stream
+    (list
+      (feed/normalize {:actor "alice" :object "pub" :at 10})
+      (feed/normalize {:actor "bob" :object "sec" :visible-to (list "carol") :at 20})
+      (feed/normalize {:actor "frank" :object "dm" :visible-to (list "dave") :at 30}))))
+
+(feed-test
+  "public visible to anyone"
+  (feed/count (feed/visible C "zoe" feed/permit-acl?))
+  1)
+(feed-test
+  "carol sees allowlisted + public"
+  (feed/count (feed/visible C "carol" feed/permit-acl?))
+  2)
+(feed-test
+  "dave sees dm + public"
+  (feed/count (feed/visible C "dave" feed/permit-acl?))
+  2)
+(feed-test
+  "author always sees own private"
+  (feed/count (feed/visible C "frank" feed/permit-acl?))
+  2)
+(feed-test
+  "permit-public? lets all through"
+  (feed/count (feed/visible C "zoe" feed/permit-public?))
+  3)
+(feed-test
+  "visible objects for dave"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/visible C "dave" feed/permit-acl?)))
+  (list "pub" "dm"))
+
+; per-viewer: same stream, different timelines
+(feed-test
+  "zoe timeline differs from carol"
+  (not
+    (=
+      (feed/count (feed/visible C "zoe" feed/permit-acl?))
+      (feed/count (feed/visible C "carol" feed/permit-acl?))))
+  true)
+
+; ---------- federation: merge / ingest ----------
+
+(define
+  L
+  (feed/stream
+    (list
+      (feed/activity "alice" "post" "p1" 10 (list))
+      (feed/activity "alice" "post" "p2" 20 (list)))))
+(define
+  P
+  (feed/stream
+    (list
+      (feed/activity "alice" "post" "p2" 20 (list))
+      (feed/activity "peer" "post" "p9" 25 (list)))))
+
+(feed-test "merge concatenates" (feed/count (feed/merge L P)) 4)
+(feed-test
+  "ingest dedupes overlap"
+  (feed/count (feed/ingest L P))
+  3)
+
+(feed-test
+  "inbound normalizes + ingests"
+  (feed/count (feed/inbound L (list {:actor "peer" :object "p9" :at 25} {:actor "alice" :object "p1" :at 10})))
+  3)
+
+; backfill via injected fetch-fn
+(define peer-history (fn (peer-id) (list {:actor peer-id :object "h1" :at 1} {:actor peer-id :object "h2" :at 2})))
+(feed-test
+  "backfill merges peer history"
+  (feed/count (feed/backfill L peer-history "remote"))
+  4)
+(feed-test
+  "backfill objects present"
+  (map
+    (fn (a) (get a :object))
+    (feed/items
+      (feed/by-actor (feed/backfill L peer-history "remote") "remote")))
+  (list "h1" "h2"))
+
+; ---------- federation: outbound partition ----------
+
+; bob (local), alice@remote + carol@remote (remote) follow star
+(define
+  Gf
+  (feed/follow-graph
+    (list
+      (list "bob" "star")
+      (list "alice@remote" "star")
+      (list "carol@remote" "star"))))
+(define
+  Sf
+  (feed/stream (list (feed/activity "star" "post" "s1" 1 (list)))))
+(define
+  remote?
+  (fn (id) (feed/-elem? id (list "alice@remote" "carol@remote"))))
+(define parts (feed/federate Sf Gf remote?))
+
+(feed-test "local deliveries" (feed/count (get parts :local)) 1)
+(feed-test "remote deliveries" (feed/count (get parts :remote)) 2)
+(feed-test
+  "local recipient is bob"
+  (feed/recipients (get parts :local))
+  (list "bob"))
+
+; deliver: send-fn receives each remote event, local inbox returned
+(define sent (list))
+(define send-fn (fn (to act) (set! sent (append sent (list to)))))
+(define local-inbox (feed/deliver Sf Gf remote? send-fn))
+(feed-test "deliver returns local inbox" (feed/count local-inbox) 1)
+(feed-test "deliver sent to both remotes" (len sent) 2)
+(feed-test "deliver remote targets" sent (list "alice@remote" "carol@remote"))
+
+; ---------- end-to-end: federated, ACL-filtered, ranked timeline ----------
+
+(define
+  base
+  (feed/stream
+    (list
+      (feed/normalize {:actor "alice" :object "a1" :at 100})
+      (feed/normalize {:actor "bob" :object "b1" :visible-to (list "carol") :at 90})
+      (feed/normalize {:actor "eve" :object "e1" :visible-to (list "dave") :at 80}))))
+(define federated (feed/inbound base (list {:actor "peer" :object "x1" :at 110})))
+(define rec (feed/recency 120 10))
+(define
+  carol-tl
+  (feed/timeline federated "carol" feed/permit-acl? rec 3))
+
+; eve's :visible-to excludes carol -> filtered out; peer/alice public, bob allows carol
+(feed-test "carol federated timeline count" (feed/count carol-tl) 3)
+(feed-test
+  "carol timeline order (recency)"
+  (map (fn (a) (get a :object)) (feed/items carol-tl))
+  (list "x1" "a1" "b1"))
+(feed-test
+  "eve dm excluded from carol"
+  (feed/-elem? "e1" (map (fn (a) (get a :object)) (feed/items carol-tl)))
+  false)
+(feed-test
+  "dave sees eve dm not bob"
+  (map
+    (fn (a) (get a :object))
+    (feed/items
+      (feed/timeline federated "dave" feed/permit-acl? rec 5)))
+  (list "x1" "a1" "e1"))

lib/feed/tests/mute.sx

@@ -0,0 +1,68 @@
+; Follow-up — viewer mute/block filtering. (feed-test name got expected)
+
+(define
+  S
+  (feed/stream
+    (list
+      (feed/normalize {:actor "alice" :object "P1" :at 1 :tags (list "news")})
+      (feed/normalize {:actor "bob" :object "P2" :at 2 :tags (list "spam")})
+      (feed/normalize {:actor "alice" :object "P3" :at 3 :tags (list "cats")})
+      (feed/normalize {:actor "carol" :object "P4" :at 4 :tags (list "news" "spam")}))))
+
+; ---------- mute actors ----------
+
+(feed-test
+  "mute bob drops his post"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/mute-actors S (list "bob"))))
+  (list "P1" "P3" "P4"))
+(feed-test
+  "mute alice drops two"
+  (feed/count (feed/mute-actors S (list "alice")))
+  2)
+(feed-test
+  "mute nobody keeps all"
+  (feed/count (feed/mute-actors S (list)))
+  4)
+
+; ---------- mute tags ----------
+
+(feed-test
+  "mute spam tag drops two"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/mute-tags S (list "spam"))))
+  (list "P1" "P3"))
+(feed-test
+  "mute news+cats leaves spam-only"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/mute-tags S (list "news" "cats"))))
+  (list "P2"))
+
+; ---------- mute objects ----------
+
+(feed-test
+  "mute object P3 (thread mute)"
+  (feed/count (feed/mute-objects S (list "P3")))
+  3)
+
+; ---------- combined prefs ----------
+
+(feed-test
+  "apply-prefs actors + tags"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/apply-prefs S {:mute-actors (list "bob") :mute-tags (list "cats")})))
+  (list "P1" "P4"))
+(feed-test
+  "apply-prefs empty keeps all"
+  (feed/count (feed/apply-prefs S {}))
+  4)
+(feed-test
+  "apply-prefs all three filters"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/apply-prefs S {:mute-objects (list "P3") :mute-actors (list "carol") :mute-tags (list "spam")})))
+  (list "P1"))

lib/feed/tests/notify.sx

@@ -0,0 +1,69 @@
+; Follow-up — notification feed over an inbox. (feed-test name got expected)
+
+; an inbox is a stream of {:to receiver :activity act} events
+(define mk-ev (fn (to act) {:activity act :to to}))
+
+(define
+  IB
+  (feed/stream
+    (list
+      (mk-ev "alice" (feed/activity "bob" "like" "P" 10 (list)))
+      (mk-ev "alice" (feed/activity "carol" "like" "P" 20 (list)))
+      (mk-ev "alice" (feed/activity "dave" "reply" "Q" 30 (list)))
+      (mk-ev "bob" (feed/activity "eve" "like" "R" 40 (list))))))
+
+; ---------- raw notifications ----------
+
+(feed-test
+  "alice notification count"
+  (feed/count (feed/notifications IB "alice"))
+  3)
+(feed-test
+  "bob notification count"
+  (feed/count (feed/notifications IB "bob"))
+  1)
+(feed-test
+  "zoe no notifications"
+  (feed/count (feed/notifications IB "zoe"))
+  0)
+
+; ---------- verb filtering ----------
+
+(feed-test
+  "alice likes only"
+  (feed/count (feed/notify-verbs IB "alice" (list "like")))
+  2)
+(feed-test
+  "alice replies only"
+  (feed/count (feed/notify-verbs IB "alice" (list "reply")))
+  1)
+(feed-test
+  "alice like+reply"
+  (feed/count (feed/notify-verbs IB "alice" (list "like" "reply")))
+  3)
+(feed-test
+  "alice follow (none)"
+  (feed/count (feed/notify-verbs IB "alice" (list "follow")))
+  0)
+
+; ---------- digest ----------
+
+(define dig (feed/notify-digest IB "alice"))
+
+(feed-test "digest group count" (len dig) 2)
+(feed-test
+  "digest sorted by key (like|P before reply|Q)"
+  (map (fn (g) (get g :object)) dig)
+  (list "P" "Q"))
+(feed-test
+  "like group actors"
+  (get (nth dig 0) :actors)
+  (list "bob" "carol"))
+(feed-test "like group count" (get (nth dig 0) :count) 2)
+(feed-test "like group verb" (get (nth dig 0) :verb) "like")
+(feed-test "reply group count" (get (nth dig 1) :count) 1)
+(feed-test
+  "reply group actors"
+  (get (nth dig 1) :actors)
+  (list "dave"))
+(feed-test "empty digest for zoe" (feed/notify-digest IB "zoe") (list))

lib/feed/tests/page.sx

@@ -0,0 +1,86 @@
+; Follow-up — pagination (offset + cursor). (feed-test name got expected)
+
+; ---------- offset / limit ----------
+
+(define
+  O
+  (feed/stream
+    (list
+      (feed/activity "u" "post" "o1" 1 (list))
+      (feed/activity "u" "post" "o2" 2 (list))
+      (feed/activity "u" "post" "o3" 3 (list))
+      (feed/activity "u" "post" "o4" 4 (list))
+      (feed/activity "u" "post" "o5" 5 (list)))))
+
+(feed-test
+  "page 1"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/page O 0 2)))
+  (list "o1" "o2"))
+(feed-test
+  "page 2"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/page O 2 2)))
+  (list "o3" "o4"))
+(feed-test
+  "page 3 (partial)"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/page O 4 2)))
+  (list "o5"))
+(feed-test
+  "page past end empty"
+  (feed/count (feed/page O 10 2))
+  0)
+(feed-test "page-count 5/2 = 3" (feed/page-count O 2) 3)
+(feed-test "page-count 5/5 = 1" (feed/page-count O 5) 1)
+
+; ---------- cursor (recency) ----------
+
+(define
+  R
+  (feed/stream
+    (list
+      (feed/activity "u" "post" "a" 50 (list))
+      (feed/activity "u" "post" "b" 40 (list))
+      (feed/activity "u" "post" "c" 30 (list))
+      (feed/activity "u" "post" "d" 20 (list))
+      (feed/activity "u" "post" "e" 10 (list)))))
+
+(define p1 (feed/page-before R 100 2))
+(feed-test
+  "cursor page 1 newest first"
+  (map (fn (a) (get a :object)) (feed/items p1))
+  (list "a" "b"))
+(feed-test "next cursor after page 1" (feed/next-cursor p1) 40)
+
+(define p2 (feed/page-before R (feed/next-cursor p1) 2))
+(feed-test
+  "cursor page 2"
+  (map (fn (a) (get a :object)) (feed/items p2))
+  (list "c" "d"))
+(feed-test "next cursor after page 2" (feed/next-cursor p2) 20)
+
+(define p3 (feed/page-before R (feed/next-cursor p2) 2))
+(feed-test
+  "cursor page 3 (partial)"
+  (map (fn (a) (get a :object)) (feed/items p3))
+  (list "e"))
+
+(feed-test
+  "empty page nil cursor"
+  (feed/next-cursor (feed/page-before R 5 2))
+  nil)
+
+(feed-test
+  "after cursor loads newer"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/recent (feed/after R 30))))
+  (list "a" "b"))
+(feed-test
+  "before cursor count"
+  (feed/count (feed/before R 30))
+  2)

lib/feed/tests/rank.sx

@@ -0,0 +1,160 @@
+; Phase 3 — aggregation + ranking. (feed-test name got expected)
+
+; ---------- aggregation ----------
+
+(define
+  A
+  (feed/stream
+    (list
+      (feed/activity "alice" "post" "p1" 5 (list))
+      (feed/activity "alice" "post" "p2" 15 (list))
+      (feed/activity "bob" "post" "p3" 25 (list))
+      (feed/activity "alice" "like" "p1" 35 (list)))))
+
+(feed-test "actor-counts" (feed/actor-counts A) {:alice 3 :bob 1})
+(feed-test "object-counts" (feed/object-counts A) {:p2 1 :p3 1 :p1 2})
+(feed-test
+  "group-by actor alice len"
+  (len (get (feed/group-by A feed/actor) "alice"))
+  3)
+(feed-test
+  "group-count empty"
+  (feed/group-count feed/empty feed/actor)
+  {})
+
+; day bucketing
+(define
+  D
+  (feed/stream
+    (list
+      (feed/activity "alice" "post" "p1" 5 (list))
+      (feed/activity "alice" "post" "p2" 8 (list))
+      (feed/activity "alice" "post" "p3" 12 (list)))))
+
+(feed-test "feed/day floor" (feed/day 12 10) 1)
+(feed-test "feed/day same bucket" (feed/day 8 10) 0)
+(feed-test "by-actor-day" (feed/by-actor-day D 10) {:alice#0 2 :alice#1 1})
+
+; ---------- recency ----------
+
+(define rec (feed/recency 100 10))
+(feed-test
+  "recency at=now -> 1"
+  (rec (feed/activity "x" "post" "o" 100 (list)))
+  1)
+(feed-test
+  "recency age=hl -> .5"
+  (rec (feed/activity "x" "post" "o" 90 (list)))
+  0.5)
+(feed-test
+  "recency age=2hl -> .25"
+  (rec (feed/activity "x" "post" "o" 80 (list)))
+  0.25)
+
+; ---------- velocity ----------
+
+(define vel (feed/velocity D 10))
+(feed-test
+  "velocity burst (at=12)"
+  (vel (feed/activity "alice" "post" "z" 12 (list)))
+  3)
+(feed-test
+  "velocity mid (at=8)"
+  (vel (feed/activity "alice" "post" "z" 8 (list)))
+  2)
+(feed-test
+  "velocity first (at=5)"
+  (vel (feed/activity "alice" "post" "z" 5 (list)))
+  1)
+(feed-test
+  "velocity other actor"
+  (vel (feed/activity "bob" "post" "z" 12 (list)))
+  0)
+
+; ---------- engagement ----------
+
+(define eng (feed/engagement A))
+(feed-test
+  "engagement p1"
+  (eng (feed/activity "x" "post" "p1" 0 (list)))
+  2)
+(feed-test
+  "engagement p2"
+  (eng (feed/activity "x" "post" "p2" 0 (list)))
+  1)
+
+; ---------- composite ----------
+
+(define
+  cmp1
+  (feed/composite (list (list 2 (fn (a) (get a :at))))))
+(feed-test
+  "composite single part"
+  (cmp1 (feed/activity "x" "post" "o" 5 (list)))
+  10)
+(define
+  cmp2
+  (feed/composite
+    (list
+      (list 2 (fn (a) (get a :at)))
+      (list 3 (fn (a) 1)))))
+(feed-test
+  "composite two parts"
+  (cmp2 (feed/activity "x" "post" "o" 5 (list)))
+  13)
+
+; ---------- ranking ----------
+
+(define
+  R
+  (feed/stream
+    (list
+      (feed/activity "u" "post" "oC" 80 (list))
+      (feed/activity "u" "post" "oA" 100 (list))
+      (feed/activity "u" "post" "oB" 90 (list)))))
+
+(feed-test
+  "rank by recency objects"
+  (map (fn (a) (get a :object)) (feed/items (feed/rank R rec)))
+  (list "oA" "oB" "oC"))
+(feed-test
+  "top-2 by recency"
+  (map (fn (a) (get a :object)) (feed/items (feed/top R rec 2)))
+  (list "oA" "oB"))
+(feed-test "top-2 count" (feed/count (feed/top R rec 2)) 2)
+
+; constant score -> tiebreak by :at descending
+(define
+  T
+  (feed/stream
+    (list
+      (feed/activity "u" "post" "f" 10 (list))
+      (feed/activity "u" "post" "g" 30 (list))
+      (feed/activity "u" "post" "h" 20 (list)))))
+(feed-test
+  "tiebreak at-desc"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/rank T (fn (a) 0))))
+  (list "g" "h" "f"))
+
+; equal score AND equal :at -> stable input order
+(define
+  E
+  (feed/stream
+    (list
+      (feed/activity "u" "post" "first" 50 (list))
+      (feed/activity "u" "post" "second" 50 (list)))))
+(feed-test
+  "stable equal-key input order"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/rank E (fn (a) 0))))
+  (list "first" "second"))
+
+(feed-test
+  "with-scores attaches score"
+  (get (nth (feed/items (feed/with-scores R rec)) 1) :score)
+  1)
+
+(feed-test "rank preserves count" (feed/count (feed/rank A rec)) 4)

lib/feed/tests/thread.sx

@@ -0,0 +1,49 @@
+; Follow-up — conversation threading via :reply-to closure. (feed-test name got expected)
+
+(define
+  S
+  (feed/stream
+    (list
+      (feed/normalize {:actor "a" :object "root" :at 1})
+      (feed/normalize {:actor "b" :object "r1" :at 2 :verb "reply" :reply-to "root"})
+      (feed/normalize {:actor "c" :object "r2" :at 3 :verb "reply" :reply-to "root"})
+      (feed/normalize {:actor "d" :object "r3" :at 4 :verb "reply" :reply-to "r1"})
+      (feed/normalize {:actor "e" :object "x" :at 5}))))
+
+; ---------- direct replies ----------
+
+(feed-test "direct replies to root" (feed/reply-count S "root") 2)
+(feed-test "direct replies to r1" (feed/reply-count S "r1") 1)
+(feed-test "no replies to r3" (feed/reply-count S "r3") 0)
+(feed-test
+  "replies objects to root"
+  (map (fn (a) (get a :object)) (feed/items (feed/replies S "root")))
+  (list "r1" "r2"))
+
+; ---------- thread closure ----------
+
+(feed-test
+  "thread objects root (transitive)"
+  (feed/thread-objects S "root")
+  (list "root" "r1" "r2" "r3"))
+(feed-test
+  "thread root chronological"
+  (map (fn (a) (get a :object)) (feed/items (feed/thread S "root")))
+  (list "root" "r1" "r2" "r3"))
+(feed-test "thread size root" (feed/thread-size S "root") 4)
+(feed-test
+  "thread excludes unrelated x"
+  (feed/-elem?
+    "x"
+    (map (fn (a) (get a :object)) (feed/items (feed/thread S "root"))))
+  false)
+
+; ---------- sub-thread ----------
+
+(feed-test
+  "thread from r1 (sub-tree)"
+  (map (fn (a) (get a :object)) (feed/items (feed/thread S "r1")))
+  (list "r1" "r3"))
+(feed-test "thread size r1" (feed/thread-size S "r1") 2)
+(feed-test "leaf thread is itself" (feed/thread-size S "r3") 1)
+(feed-test "unrelated thread is itself" (feed/thread-size S "x") 1)

lib/feed/tests/trending.sx

@@ -0,0 +1,82 @@
+; Follow-up — trending objects/actors by recent activity. (feed-test name got expected)
+
+; window (50,100]: X@60,X@70 (a), Y@80 (b), Z@90 (c); W@40 is too old
+(define
+  S
+  (feed/stream
+    (list
+      (feed/activity "a" "post" "X" 60 (list))
+      (feed/activity "a" "post" "X" 70 (list))
+      (feed/activity "b" "post" "Y" 80 (list))
+      (feed/activity "c" "post" "Z" 90 (list))
+      (feed/activity "d" "post" "W" 40 (list)))))
+
+; ---------- trending objects ----------
+
+(feed-test
+  "trending count (3 in window)"
+  (len (feed/trending S 100 50 10))
+  3)
+(feed-test
+  "trending top object"
+  (get
+    (nth (feed/trending S 100 50 10) 0)
+    :object)
+  "X")
+(feed-test
+  "trending top count"
+  (get
+    (nth (feed/trending S 100 50 10) 0)
+    :count)
+  2)
+(feed-test
+  "trending order (count desc, key asc tiebreak)"
+  (map
+    (fn (e) (get e :object))
+    (feed/trending S 100 50 10))
+  (list "X" "Y" "Z"))
+(feed-test
+  "trending top-2"
+  (map
+    (fn (e) (get e :object))
+    (feed/trending S 100 50 2))
+  (list "X" "Y"))
+(feed-test
+  "old object W excluded"
+  (feed/-elem?
+    "W"
+    (map
+      (fn (e) (get e :object))
+      (feed/trending S 100 50 10)))
+  false)
+(feed-test
+  "narrow window keeps only newest"
+  (map
+    (fn (e) (get e :object))
+    (feed/trending S 100 15 10))
+  (list "Z"))
+(feed-test
+  "empty window -> nothing"
+  (feed/trending S 100 5 10)
+  (list))
+
+; ---------- trending actors ----------
+
+(feed-test
+  "trending actor top"
+  (get
+    (nth (feed/trending-actors S 100 50 10) 0)
+    :actor)
+  "a")
+(feed-test
+  "trending actor count"
+  (get
+    (nth (feed/trending-actors S 100 50 10) 0)
+    :count)
+  2)
+(feed-test
+  "trending actors order"
+  (map
+    (fn (e) (get e :actor))
+    (feed/trending-actors S 100 50 10))
+  (list "a" "b" "c"))

lib/feed/thread.sx

@@ -0,0 +1,59 @@
+; feed/thread — conversation threading. A reply carries :reply-to <parent-object>
+; (normalize preserves it). A thread is the transitive closure over :reply-to from
+; a root object: root + replies + replies-to-replies, gathered chronologically.
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx, lib/feed/fanout.sx
+; (feed/-elem?, feed/-distinct).
+
+; direct replies to an object
+(define
+  feed/replies
+  (fn
+    (stream object)
+    (feed/filter stream (fn (a) (equal? (get a :reply-to) object)))))
+
+(define
+  feed/reply-count
+  (fn (stream object) (feed/count (feed/replies stream object))))
+
+; iterate f from x until the result stops growing (set-closure fixpoint)
+(define
+  feed/-fixpoint
+  (fn
+    (f x)
+    (let
+      ((nx (f x)))
+      (if (= (len nx) (len x)) x (feed/-fixpoint f nx)))))
+
+; the set of object-ids in the thread rooted at `root`
+(define
+  feed/thread-objects
+  (fn
+    (stream root)
+    (let
+      ((all (feed/items stream)))
+      (feed/-fixpoint
+        (fn
+          (acc)
+          (feed/-distinct
+            (append
+              acc
+              (map
+                (fn (a) (get a :object))
+                (filter (fn (a) (feed/-elem? (get a :reply-to) acc)) all)))))
+        (list root)))))
+
+; the full thread as a chronological stream (root + all descendants)
+(define
+  feed/thread
+  (fn
+    (stream root)
+    (let
+      ((objs (feed/thread-objects stream root)))
+      (feed/sort-by-at
+        (feed/filter stream (fn (a) (feed/-elem? (get a :object) objs)))))))
+
+; how many activities are in the thread (root counts as 1)
+(define
+  feed/thread-size
+  (fn (stream root) (feed/count (feed/thread stream root))))

lib/feed/trending.sx

@@ -0,0 +1,42 @@
+; feed/trending — what's hot right now: objects (or actors) ranked by activity
+; count within a recency window. Deterministic: count descending, ties broken by
+; key ascending (entries are pre-sorted by key, then stable grade-down by count).
+;
+; Requires: lib/feed/stream.sx, lib/feed/aggregate.sx (object/actor-counts),
+; lib/feed/rank.sx (feed/-desc-by).
+
+; activities within (now-window, now]
+(define
+  feed/-recent
+  (fn
+    (stream now window)
+    (feed/filter
+      stream
+      (fn (a) (and (<= (get a :at) now) (> (get a :at) (- now window)))))))
+
+; counts dict -> top-N entries {label key, :count n}, count desc, key asc
+(define
+  feed/-top-counts
+  (fn
+    (counts label n)
+    (let
+      ((entries (map (fn (k) (assoc {:count (get counts k)} label k)) (sort (keys counts)))))
+      (take (feed/-desc-by entries (fn (e) (get e :count))) n))))
+
+; top-N trending objects in the window
+(define
+  feed/trending
+  (fn
+    (stream now window n)
+    (feed/-top-counts
+      (feed/object-counts (feed/-recent stream now window))
+      :object n)))
+
+; top-N most active actors in the window
+(define
+  feed/trending-actors
+  (fn
+    (stream now window n)
+    (feed/-top-counts
+      (feed/actor-counts (feed/-recent stream now window))
+      :actor n)))

lib/go/conformance.sh

@@ -0,0 +1,141 @@
+#!/usr/bin/env bash
+# Go-on-SX conformance runner.
+#
+# Loads every Go-on-SX test suite via the epoch protocol, collects
+# pass/fail counts, and writes lib/go/scoreboard.json + .md.
+#
+# Usage:
+#   bash lib/go/conformance.sh           # run all suites
+#   bash lib/go/conformance.sh -v        # verbose per-suite
+
+set -uo pipefail
+cd "$(git rev-parse --show-toplevel)"
+
+SX_SERVER="${SX_SERVER:-hosts/ocaml/_build/default/bin/sx_server.exe}"
+if [ ! -x "$SX_SERVER" ]; then
+  SX_SERVER="/root/rose-ash/hosts/ocaml/_build/default/bin/sx_server.exe"
+fi
+if [ ! -x "$SX_SERVER" ]; then
+  echo "ERROR: sx_server.exe not found." >&2
+  exit 1
+fi
+
+VERBOSE="${1:-}"
+TMPFILE=$(mktemp)
+OUTFILE=$(mktemp)
+trap "rm -f $TMPFILE $OUTFILE" EXIT
+
+# Each suite: name | pass-counter | total-counter
+SUITES=(
+  "lex|go-test-pass|go-test-count"
+  "parse|go-parse-test-pass|go-parse-test-count"
+  "types|go-types-test-pass|go-types-test-count"
+  "eval|go-eval-test-pass|go-eval-test-count"
+  "runtime|go-rt-test-pass|go-rt-test-count"
+  "stdlib|go-std-test-pass|go-std-test-count"
+  "e2e|go-e2e-test-pass|go-e2e-test-count"
+)
+
+cat > "$TMPFILE" <<'EPOCHS'
+(epoch 1)
+(load "lib/guest/lex.sx")
+(load "lib/guest/ast.sx")
+(load "lib/guest/pratt.sx")
+(load "lib/go/lex.sx")
+(load "lib/go/parse.sx")
+(load "lib/go/types.sx")
+(load "lib/go/sched.sx")
+(load "lib/go/eval.sx")
+(load "lib/go/std/strings.sx")
+(load "lib/go/std/strconv.sx")
+(load "lib/go/tests/lex.sx")
+(load "lib/go/tests/parse.sx")
+(load "lib/go/tests/types.sx")
+(load "lib/go/tests/eval.sx")
+(load "lib/go/tests/runtime.sx")
+(load "lib/go/tests/stdlib.sx")
+(load "lib/go/tests/e2e.sx")
+EPOCHS
+
+idx=0
+for entry in "${SUITES[@]}"; do
+  name="${entry%%|*}"
+  pass_var=$(echo "$entry" | awk -F'|' '{print $2}')
+  total_var=$(echo "$entry" | awk -F'|' '{print $3}')
+  epoch=$((100 + idx))
+  echo "(epoch $epoch)" >> "$TMPFILE"
+  echo "(eval \"(list $pass_var $total_var)\")" >> "$TMPFILE"
+  idx=$((idx + 1))
+done
+
+"$SX_SERVER" < "$TMPFILE" > "$OUTFILE" 2>&1
+
+parse_pair() {
+  local epoch="$1"
+  local line
+  line=$(grep -A1 "^(ok-len $epoch " "$OUTFILE" | tail -1)
+  echo "$line" | sed -E 's/[()]//g'
+}
+
+TOTAL_PASS=0
+TOTAL_COUNT=0
+JSON_SUITES=""
+MD_ROWS=""
+
+idx=0
+for entry in "${SUITES[@]}"; do
+  name="${entry%%|*}"
+  epoch=$((100 + idx))
+  pair=$(parse_pair "$epoch")
+  pass=$(echo "$pair" | awk '{print $1}')
+  count=$(echo "$pair" | awk '{print $2}')
+  if [ -z "$pass" ] || [ -z "$count" ]; then
+    pass=0
+    count=0
+  fi
+  TOTAL_PASS=$((TOTAL_PASS + pass))
+  TOTAL_COUNT=$((TOTAL_COUNT + count))
+  status="ok"
+  marker="✅"
+  if [ "$pass" != "$count" ]; then
+    status="fail"
+    marker="❌"
+  fi
+  if [ "$VERBOSE" = "-v" ]; then
+    printf "  %-12s %s/%s\n" "$name" "$pass" "$count"
+  fi
+  if [ -n "$JSON_SUITES" ]; then JSON_SUITES+=","; fi
+  JSON_SUITES+=$'\n    '
+  JSON_SUITES+="{\"name\":\"$name\",\"pass\":$pass,\"total\":$count,\"status\":\"$status\"}"
+  MD_ROWS+="| $marker | $name | $pass | $count |"$'\n'
+  idx=$((idx + 1))
+done
+
+printf '\nGo-on-SX conformance: %d / %d\n' "$TOTAL_PASS" "$TOTAL_COUNT"
+
+cat > lib/go/scoreboard.json <<JSON
+{
+  "language": "go",
+  "total_pass": $TOTAL_PASS,
+  "total": $TOTAL_COUNT,
+  "suites": [$JSON_SUITES]
+}
+JSON
+
+cat > lib/go/scoreboard.md <<MD
+# Go-on-SX Scoreboard
+
+**Total: ${TOTAL_PASS} / ${TOTAL_COUNT} tests passing**
+
+|  | Suite | Pass | Total |
+|---|---|---|---|
+$MD_ROWS
+
+Generated by \`lib/go/conformance.sh\`.
+MD
+
+if [ "$TOTAL_PASS" -eq "$TOTAL_COUNT" ]; then
+  exit 0
+else
+  exit 1
+fi

lib/go/lex.sx

@@ -0,0 +1,476 @@
+;; lib/go/lex.sx — Go tokenizer with automatic semicolon insertion.
+;;
+;; Consumes lib/guest/lex.sx character-class predicates.
+;;
+;; Tokens: {:type T :value V :pos P}
+;; Types:
+;;   "ident"   — identifiers (foo, _bar, mixedCase)
+;;   "keyword" — one of the 25 Go keywords
+;;   "int"     — integer literals (decimal, 0x.. hex, 0b.. binary, 0o.. octal,
+;;               legacy 0123 octal; underscores between digits allowed)
+;;   "float"   — decimal float literals (3.14, .5, 1., 1e10, 1.5e-3, 1E5)
+;;   "imag"    — imaginary literals (2i, 3.14i, 1e2i)
+;;   "string"  — interpreted string literals "..." OR raw string literals `...`
+;;   "rune"    — rune literals 'x' (single char + simple escapes)
+;;   "op"      — operators & punctuation; :value is the literal text
+;;   "semi"    — explicit ';' or auto-inserted (Go spec § Semicolons)
+;;   "eof"     — end-of-input sentinel
+;;
+;; ASI (Go spec § Semicolons): a newline (or EOF, or a block comment
+;; containing a newline) emits a ";semi" if the previous emitted token's
+;; type is ident/int/float/imag/string/rune, or its value is one of
+;;   {break, continue, fallthrough, return, ++, --, ), ], }}.
+;;
+;; All scanner locals are gl- prefixed: SX host primitives (peek/emit/etc.)
+;; silently shadow guest-language defines. See feedback_sx_bind_clash.
+
+(define
+  go-keywords
+  (list
+    "break"
+    "case"
+    "chan"
+    "const"
+    "continue"
+    "default"
+    "defer"
+    "else"
+    "fallthrough"
+    "for"
+    "func"
+    "go"
+    "goto"
+    "if"
+    "import"
+    "interface"
+    "map"
+    "package"
+    "range"
+    "return"
+    "select"
+    "struct"
+    "switch"
+    "type"
+    "var"))
+
+(define go-keyword? (fn (s) (some (fn (k) (= k s)) go-keywords)))
+
+(define go-asi-keywords (list "break" "continue" "fallthrough" "return"))
+
+(define go-asi-ops (list "++" "--" ")" "]" "}"))
+
+(define go-asi-lit-types (list "ident" "int" "float" "imag" "string" "rune"))
+
+(define
+  go-asi-trigger?
+  (fn
+    (tok)
+    (if
+      (= tok nil)
+      false
+      (let
+        ((ty (get tok :type)) (v (get tok :value)))
+        (or
+          (some (fn (lt) (= lt ty)) go-asi-lit-types)
+          (and (= ty "keyword") (some (fn (k) (= k v)) go-asi-keywords))
+          (and (= ty "op") (some (fn (o) (= o v)) go-asi-ops)))))))
+
+(define
+  go-tokenize
+  (fn
+    (src)
+    (let
+      ((tokens (list)) (pos 0) (src-len (len src)))
+      (define
+        gl-peek
+        (fn
+          (offset)
+          (if (< (+ pos offset) src-len) (nth src (+ pos offset)) nil)))
+      (define gl-cur (fn () (gl-peek 0)))
+      (define gl-advance! (fn (n) (set! pos (+ pos n))))
+      (define
+        gl-last
+        (fn
+          ()
+          (if
+            (= (len tokens) 0)
+            nil
+            (nth tokens (- (len tokens) 1)))))
+      (define gl-emit! (fn (type value start) (append! tokens {:type type :value value :pos start})))
+      (define
+        gl-maybe-asi!
+        (fn
+          (at)
+          (when (go-asi-trigger? (gl-last)) (gl-emit! "semi" "\n" at))))
+      (define
+        gl-oct-digit?
+        (fn (c) (and (not (= c nil)) (>= c "0") (<= c "7"))))
+      (define gl-bin-digit? (fn (c) (or (= c "0") (= c "1"))))
+      (define
+        gl-skip-line!
+        (fn
+          ()
+          (when
+            (and (< pos src-len) (not (= (gl-cur) "\n")))
+            (gl-advance! 1)
+            (gl-skip-line!))))
+      (define
+        gl-skip-block!
+        (fn
+          (saw-nl)
+          (cond
+            (>= pos src-len)
+            saw-nl
+            (and (= (gl-cur) "*") (= (gl-peek 1) "/"))
+            (do (gl-advance! 2) saw-nl)
+            :else (let
+              ((is-nl (= (gl-cur) "\n")))
+              (gl-advance! 1)
+              (gl-skip-block! (or saw-nl is-nl))))))
+      (define
+        gl-read-ident!
+        (fn
+          (start)
+          (when
+            (and (< pos src-len) (lex-ident-char? (gl-cur)))
+            (gl-advance! 1)
+            (gl-read-ident! start))
+          (slice src start pos)))
+      (define
+        gl-read-digit-run!
+        (fn
+          (digit?)
+          (when
+            (and (< pos src-len) (or (digit? (gl-cur)) (= (gl-cur) "_")))
+            (gl-advance! 1)
+            (gl-read-digit-run! digit?))))
+      (define
+        gl-finish-number!
+        (fn
+          (has-fraction?)
+          (let
+            ((typ (if has-fraction? "float" "int")))
+            (when
+              (or (= (gl-cur) "e") (= (gl-cur) "E"))
+              (gl-advance! 1)
+              (when
+                (or (= (gl-cur) "+") (= (gl-cur) "-"))
+                (gl-advance! 1))
+              (gl-read-digit-run! lex-digit?)
+              (set! typ "float"))
+            (cond
+              (= (gl-cur) "i")
+              (do (gl-advance! 1) "imag")
+              :else typ))))
+      (define
+        gl-read-number!
+        (fn
+          ()
+          (cond
+            (and (= (gl-cur) ".") (lex-digit? (gl-peek 1)))
+            (do
+              (gl-advance! 1)
+              (gl-read-digit-run! lex-digit?)
+              (gl-finish-number! true))
+            (and
+              (= (gl-cur) "0")
+              (or
+                (= (gl-peek 1) "x")
+                (= (gl-peek 1) "X")))
+            (do
+              (gl-advance! 2)
+              (gl-read-digit-run! lex-hex-digit?)
+              "int")
+            (and
+              (= (gl-cur) "0")
+              (or
+                (= (gl-peek 1) "b")
+                (= (gl-peek 1) "B")))
+            (do
+              (gl-advance! 2)
+              (gl-read-digit-run! gl-bin-digit?)
+              "int")
+            (and
+              (= (gl-cur) "0")
+              (or
+                (= (gl-peek 1) "o")
+                (= (gl-peek 1) "O")))
+            (do
+              (gl-advance! 2)
+              (gl-read-digit-run! gl-oct-digit?)
+              "int")
+            :else (do
+              (gl-read-digit-run! lex-digit?)
+              (cond
+                (and (= (gl-cur) ".") (not (= (gl-peek 1) ".")))
+                (do
+                  (gl-advance! 1)
+                  (gl-read-digit-run! lex-digit?)
+                  (gl-finish-number! true))
+                :else (gl-finish-number! false))))))
+      (define
+        gl-read-string!
+        (fn
+          ()
+          (gl-advance! 1)
+          (let
+            ((chars (list)))
+            (define
+              gl-string-loop
+              (fn
+                ()
+                (cond
+                  (>= pos src-len)
+                  nil
+                  (= (gl-cur) "\"")
+                  (gl-advance! 1)
+                  (= (gl-cur) "\\")
+                  (do
+                    (gl-advance! 1)
+                    (when
+                      (< pos src-len)
+                      (let
+                        ((ch (gl-cur)))
+                        (cond
+                          (= ch "n")
+                          (append! chars "\n")
+                          (= ch "t")
+                          (append! chars "\t")
+                          (= ch "r")
+                          (append! chars "\r")
+                          (= ch "\\")
+                          (append! chars "\\")
+                          (= ch "\"")
+                          (append! chars "\"")
+                          (= ch "'")
+                          (append! chars "'")
+                          :else (append! chars ch))
+                        (gl-advance! 1)))
+                    (gl-string-loop))
+                  :else (do
+                    (append! chars (gl-cur))
+                    (gl-advance! 1)
+                    (gl-string-loop)))))
+            (gl-string-loop)
+            (join "" chars))))
+      (define
+        gl-read-raw-string!
+        (fn
+          ()
+          (gl-advance! 1)
+          (let
+            ((chars (list)))
+            (define
+              gl-raw-loop
+              (fn
+                ()
+                (cond
+                  (>= pos src-len)
+                  nil
+                  (= (gl-cur) "`")
+                  (gl-advance! 1)
+                  (= (gl-cur) "\r")
+                  (do (gl-advance! 1) (gl-raw-loop))
+                  :else (do
+                    (append! chars (gl-cur))
+                    (gl-advance! 1)
+                    (gl-raw-loop)))))
+            (gl-raw-loop)
+            (join "" chars))))
+      (define
+        gl-read-rune!
+        (fn
+          ()
+          (gl-advance! 1)
+          (let
+            ((chars (list)))
+            (cond
+              (and (< pos src-len) (= (gl-cur) "\\"))
+              (do
+                (gl-advance! 1)
+                (when
+                  (< pos src-len)
+                  (let
+                    ((ch (gl-cur)))
+                    (cond
+                      (= ch "n")
+                      (append! chars "\n")
+                      (= ch "t")
+                      (append! chars "\t")
+                      (= ch "r")
+                      (append! chars "\r")
+                      (= ch "\\")
+                      (append! chars "\\")
+                      (= ch "'")
+                      (append! chars "'")
+                      (= ch "\"")
+                      (append! chars "\"")
+                      :else (append! chars ch))
+                    (gl-advance! 1))))
+              (< pos src-len)
+              (do (append! chars (gl-cur)) (gl-advance! 1)))
+            (when
+              (and (< pos src-len) (= (gl-cur) "'"))
+              (gl-advance! 1))
+            (join "" chars))))
+      (define
+        gl-match-op
+        (fn
+          ()
+          (let
+            ((c0 (gl-cur))
+              (c1 (gl-peek 1))
+              (c2 (gl-peek 2)))
+            (cond
+              (and (= c0 "<") (= c1 "<") (= c2 "="))
+              "<<="
+              (and (= c0 ">") (= c1 ">") (= c2 "="))
+              ">>="
+              (and (= c0 "&") (= c1 "^") (= c2 "="))
+              "&^="
+              (and (= c0 ".") (= c1 ".") (= c2 "."))
+              "..."
+              (and (= c0 "=") (= c1 "="))
+              "=="
+              (and (= c0 "!") (= c1 "="))
+              "!="
+              (and (= c0 "<") (= c1 "="))
+              "<="
+              (and (= c0 ">") (= c1 "="))
+              ">="
+              (and (= c0 "&") (= c1 "&"))
+              "&&"
+              (and (= c0 "|") (= c1 "|"))
+              "||"
+              (and (= c0 "+") (= c1 "+"))
+              "++"
+              (and (= c0 "-") (= c1 "-"))
+              "--"
+              (and (= c0 "<") (= c1 "<"))
+              "<<"
+              (and (= c0 ">") (= c1 ">"))
+              ">>"
+              (and (= c0 "+") (= c1 "="))
+              "+="
+              (and (= c0 "-") (= c1 "="))
+              "-="
+              (and (= c0 "*") (= c1 "="))
+              "*="
+              (and (= c0 "/") (= c1 "="))
+              "/="
+              (and (= c0 "%") (= c1 "="))
+              "%="
+              (and (= c0 "&") (= c1 "="))
+              "&="
+              (and (= c0 "|") (= c1 "="))
+              "|="
+              (and (= c0 "^") (= c1 "="))
+              "^="
+              (and (= c0 ":") (= c1 "="))
+              ":="
+              (and (= c0 "<") (= c1 "-"))
+              "<-"
+              (and (= c0 "&") (= c1 "^"))
+              "&^"
+              (or
+                (= c0 "+")
+                (= c0 "-")
+                (= c0 "*")
+                (= c0 "/")
+                (= c0 "%")
+                (= c0 "&")
+                (= c0 "|")
+                (= c0 "^")
+                (= c0 "<")
+                (= c0 ">")
+                (= c0 "=")
+                (= c0 "!")
+                (= c0 "(")
+                (= c0 ")")
+                (= c0 "{")
+                (= c0 "}")
+                (= c0 "[")
+                (= c0 "]")
+                (= c0 ",")
+                (= c0 ".")
+                (= c0 ":")
+                (= c0 "~"))
+              c0
+              :else nil))))
+      (define
+        gl-scan!
+        (fn
+          ()
+          (cond
+            (>= pos src-len)
+            nil
+            (= (gl-cur) "\n")
+            (do (gl-maybe-asi! pos) (gl-advance! 1) (gl-scan!))
+            (lex-space? (gl-cur))
+            (do (gl-advance! 1) (gl-scan!))
+            (and (= (gl-cur) "/") (= (gl-peek 1) "/"))
+            (do (gl-advance! 2) (gl-skip-line!) (gl-scan!))
+            (and (= (gl-cur) "/") (= (gl-peek 1) "*"))
+            (do
+              (gl-advance! 2)
+              (let
+                ((saw-nl (gl-skip-block! false)))
+                (when saw-nl (gl-maybe-asi! pos)))
+              (gl-scan!))
+            (= (gl-cur) ";")
+            (do
+              (gl-emit! "semi" ";" pos)
+              (gl-advance! 1)
+              (gl-scan!))
+            (lex-ident-start? (gl-cur))
+            (do
+              (let
+                ((start pos))
+                (gl-read-ident! start)
+                (let
+                  ((word (slice src start pos)))
+                  (gl-emit!
+                    (if (go-keyword? word) "keyword" "ident")
+                    word
+                    start)))
+              (gl-scan!))
+            (lex-digit? (gl-cur))
+            (do
+              (let
+                ((start pos) (typ (gl-read-number!)))
+                (gl-emit! typ (slice src start pos) start))
+              (gl-scan!))
+            (and (= (gl-cur) ".") (lex-digit? (gl-peek 1)))
+            (do
+              (let
+                ((start pos) (typ (gl-read-number!)))
+                (gl-emit! typ (slice src start pos) start))
+              (gl-scan!))
+            (= (gl-cur) "\"")
+            (let
+              ((start pos) (v (gl-read-string!)))
+              (gl-emit! "string" v start)
+              (gl-scan!))
+            (= (gl-cur) "`")
+            (let
+              ((start pos) (v (gl-read-raw-string!)))
+              (gl-emit! "string" v start)
+              (gl-scan!))
+            (= (gl-cur) "'")
+            (let
+              ((start pos) (v (gl-read-rune!)))
+              (gl-emit! "rune" v start)
+              (gl-scan!))
+            :else (let
+              ((op (gl-match-op)))
+              (cond
+                op
+                (do
+                  (gl-emit! "op" op pos)
+                  (gl-advance! (len op))
+                  (gl-scan!))
+                :else (do (gl-advance! 1) (gl-scan!)))))))
+      (gl-scan!)
+      (gl-maybe-asi! pos)
+      (gl-emit! "eof" nil pos)
+      tokens)))

lib/go/sched.sx

@@ -0,0 +1,66 @@
+;; lib/go/sched.sx — Go scheduler primitives: channels + goroutines.
+;;
+;; This is **the independent implementation** referenced by
+;; plans/lib-guest-scheduler.md. The shape that emerges here informs
+;; the eventual sister kit; this file's structures are the Phase 5
+;; "first-consumer" cut.
+;;
+;; v0 concurrency model — IMPORTANT
+;;
+;; SX has no first-class continuations exposed to guest code, so we
+;; can't suspend a goroutine mid-statement. v0 runs `go f()` SYNCHRO-
+;; NOUSLY (it's an immediate call whose return value is dropped). This
+;; preserves the right semantics for patterns where the spawned
+;; goroutine simply pushes to a channel that the main goroutine then
+;; receives — because the spawned goroutine runs to completion first
+;; and leaves the value in the channel buffer.
+;;
+;; True preemption with blocking sends/recvs is a Phase 5b refinement.
+;; The sister-plan diary tracks the design insight (single
+;; sched-spawn primitive, channel-op direction tag) so the eventual
+;; kit doesn't bake in v0's synchronous limitation.
+;;
+;; Channel representation
+;;
+;;   (list :go-chan ACCESSORS-FN-LIST)
+;;
+;; ACCESSORS-FN-LIST is a list of closures sharing a mutable buffer
+;; and a closed flag. The closures expose:
+;;   index 1: send-fn     — (lambda (val) ...)
+;;   index 2: recv-fn     — (lambda () val-or-:empty)
+;;   index 3: closed?-fn  — (lambda () bool)
+;;   index 4: close!-fn   — (lambda () ...)
+;;
+;; Channel identity: distinct calls to go-make-chan produce closures
+;; with distinct identity — `(= ch1 ch2)` is false for distinct
+;; channels, matching Go spec § Channel types.
+
+(define
+  go-make-chan
+  (fn
+    ()
+    (let
+      ((buf (list)) (closed false))
+      (list
+        :go-chan (fn (v) (append! buf v) nil)
+        (fn
+          ()
+          (cond
+            (= (len buf) 0)
+            :empty :else
+            (let ((v (first buf))) (set! buf (rest buf)) v)))
+        (fn () closed)
+        (fn () (set! closed true) nil)
+        (fn () (len buf))))))
+
+(define
+  go-chan?
+  (fn
+    (v)
+    (and (list? v) (not (= (len v) 0)) (= (first v) :go-chan))))
+
+(define go-chan-send! (fn (ch val) ((nth ch 1) val)))
+(define go-chan-recv! (fn (ch) ((nth ch 2))))
+(define go-chan-closed? (fn (ch) ((nth ch 3))))
+(define go-chan-close! (fn (ch) ((nth ch 4))))
+(define go-chan-len    (fn (ch) ((nth ch 5))))

lib/go/scoreboard.json

@@ -0,0 +1,13 @@
+{
+  "language": "go",
+  "total_pass": 609,
+  "total": 609,
+  "suites": [
+    {"name":"lex","pass":129,"total":129,"status":"ok"},
+    {"name":"parse","pass":179,"total":179,"status":"ok"},
+    {"name":"types","pass":102,"total":102,"status":"ok"},
+    {"name":"eval","pass":106,"total":106,"status":"ok"},
+    {"name":"runtime","pass":40,"total":40,"status":"ok"},
+    {"name":"stdlib","pass":41,"total":41,"status":"ok"},
+    {"name":"e2e","pass":12,"total":12,"status":"ok"}]
+}

lib/go/scoreboard.md

@@ -0,0 +1,16 @@
+# Go-on-SX Scoreboard
+
+**Total: 609 / 609 tests passing**
+
+|  | Suite | Pass | Total |
+|---|---|---|---|
+| ✅ | lex | 129 | 129 |
+| ✅ | parse | 179 | 179 |
+| ✅ | types | 102 | 102 |
+| ✅ | eval | 106 | 106 |
+| ✅ | runtime | 40 | 40 |
+| ✅ | stdlib | 41 | 41 |
+| ✅ | e2e | 12 | 12 |
+
+
+Generated by `lib/go/conformance.sh`.

lib/go/std/strconv.sx

@@ -0,0 +1,71 @@
+;; lib/go/std/strconv.sx — Go's `strconv` package, v0 subset.
+
+(define
+  go-strconv-itoa
+  ;; Itoa(n) → string. Real Go returns the decimal representation.
+  (fn (args)
+    (cond
+      (not (= (len args) 1))
+      (list :eval-error :strconv-itoa-arity (len args))
+      :else
+      (let ((n (first args)))
+        (cond
+          (not (number? n)) (list :eval-error :strconv-itoa-not-number n)
+          :else (str n))))))
+
+(define
+  go-strconv-atoi
+  ;; Atoi(s) → (int, error). v0 returns just the int on success or
+  ;; an :eval-error on failure (multi-return is a later refinement).
+  (fn (args)
+    (cond
+      (not (= (len args) 1))
+      (list :eval-error :strconv-atoi-arity (len args))
+      :else
+      (let ((s (first args)))
+        (cond
+          (not (string? s)) (list :eval-error :strconv-atoi-not-string s)
+          (= (len s) 0) (list :eval-error :strconv-atoi-empty)
+          :else (go-strconv-parse-int s 0 (= (nth s 0) "-") 0))))))
+
+(define
+  go-strconv-parse-int
+  ;; Parse a (possibly signed) base-10 integer literal. Stops on the
+  ;; first non-digit char and returns the parsed prefix, or :eval-error
+  ;; if no digits were consumed.
+  (fn (s start neg acc)
+    (let ((i (cond (= start 0) (cond neg 1 :else 0) :else start)))
+      (cond
+        (>= i (len s))
+        (cond
+          (= (cond neg (- i 1) :else i) 0)
+          (list :eval-error :strconv-atoi-no-digits s)
+          :else
+          (cond neg (- 0 acc) :else acc))
+        :else
+        (let ((d (go-strconv-digit (nth s i))))
+          (cond
+            (< d 0)
+            (cond
+              (= (cond neg (- i 1) :else i) 0)
+              (list :eval-error :strconv-atoi-no-digits s)
+              :else
+              (cond neg (- 0 acc) :else acc))
+            :else
+            (go-strconv-parse-int s (+ i 1) neg (+ (* acc 10) d))))))))
+
+(define
+  go-strconv-digit
+  (fn (c)
+    (cond
+      (= c "0") 0  (= c "1") 1  (= c "2") 2  (= c "3") 3
+      (= c "4") 4  (= c "5") 5  (= c "6") 6  (= c "7") 7
+      (= c "8") 8  (= c "9") 9
+      :else -1)))
+
+(define
+  go-std-strconv
+  (list :go-package "strconv"
+    (list
+      (list "Itoa" (list :go-builtin-fn go-strconv-itoa))
+      (list "Atoi" (list :go-builtin-fn go-strconv-atoi)))))

lib/go/std/strings.sx

@@ -0,0 +1,386 @@
+;; lib/go/std/strings.sx — Go's `strings` package, v0 subset.
+;;
+;; Exposed as `go-std-strings`, a (:go-package "strings" ENTRIES) value.
+;; Register with `(go-env-extend env "strings" go-std-strings)` to make
+;; `strings.X(...)` call sites work in evaluated Go code.
+;;
+;; Each entry is (FIELD-NAME (list :go-fn PARAMS BODY)) — the same
+;; shape user-defined Go functions get. Bodies are written in SX
+;; directly via go-builtin closures wrapping host-level string ops
+;; for speed, OR as parsed Go source for fidelity. v0 uses
+;; go-builtin wrappers — simpler and fast.
+
+;; ── helpers: implement go-std-strings entries as builtins ────────
+
+(define
+  go-strings-contains
+  (fn (args)
+    (cond
+      (not (= (len args) 2))
+      (list :eval-error :strings-contains-arity (len args))
+      :else
+      (let ((s (first args)) (sub (nth args 1)))
+        (cond
+          (not (string? s)) (list :eval-error :strings-not-string s)
+          (not (string? sub)) (list :eval-error :strings-not-string sub)
+          :else
+          (go-strings-index-of s sub 0))))))
+
+(define
+  go-strings-index-of
+  ;; Returns true if SUB appears in S at or after START, else false.
+  (fn (s sub start)
+    (let ((slen (len s)) (sublen (len sub)))
+      (cond
+        (= sublen 0) true
+        (> (+ start sublen) slen) false
+        (go-strings-match-at s sub start 0) true
+        :else (go-strings-index-of s sub (+ start 1))))))
+
+(define
+  go-strings-match-at
+  (fn (s sub start k)
+    (cond
+      (>= k (len sub)) true
+      (= (nth s (+ start k)) (nth sub k))
+      (go-strings-match-at s sub start (+ k 1))
+      :else false)))
+
+(define
+  go-strings-has-prefix
+  (fn (args)
+    (cond
+      (not (= (len args) 2))
+      (list :eval-error :strings-hasprefix-arity (len args))
+      :else
+      (let ((s (first args)) (p (nth args 1)))
+        (cond
+          (not (string? s)) (list :eval-error :strings-not-string s)
+          (not (string? p)) (list :eval-error :strings-not-string p)
+          (> (len p) (len s)) false
+          :else (go-strings-match-at s p 0 0))))))
+
+(define
+  go-strings-has-suffix
+  (fn (args)
+    (cond
+      (not (= (len args) 2))
+      (list :eval-error :strings-hassuffix-arity (len args))
+      :else
+      (let ((s (first args)) (suf (nth args 1)))
+        (cond
+          (not (string? s)) (list :eval-error :strings-not-string s)
+          (not (string? suf)) (list :eval-error :strings-not-string suf)
+          (> (len suf) (len s)) false
+          :else
+          (go-strings-match-at s suf (- (len s) (len suf)) 0))))))
+
+(define
+  go-strings-index
+  (fn (args)
+    (cond
+      (not (= (len args) 2))
+      (list :eval-error :strings-index-arity (len args))
+      :else
+      (let ((s (first args)) (sub (nth args 1)))
+        (cond
+          (not (string? s)) (list :eval-error :strings-not-string s)
+          (not (string? sub)) (list :eval-error :strings-not-string sub)
+          :else (go-strings-index-loop s sub 0))))))
+
+(define
+  go-strings-index-loop
+  (fn (s sub start)
+    (let ((slen (len s)) (sublen (len sub)))
+      (cond
+        (= sublen 0) 0
+        (> (+ start sublen) slen) -1
+        (go-strings-match-at s sub start 0) start
+        :else (go-strings-index-loop s sub (+ start 1))))))
+
+(define
+  go-strings-repeat
+  (fn (args)
+    (cond
+      (not (= (len args) 2))
+      (list :eval-error :strings-repeat-arity (len args))
+      :else
+      (let ((s (first args)) (n (nth args 1)))
+        (cond
+          (not (string? s)) (list :eval-error :strings-not-string s)
+          (< n 0) (list :eval-error :strings-repeat-negative n)
+          :else (go-strings-repeat-loop s n ""))))))
+
+(define
+  go-strings-repeat-loop
+  (fn (s n acc)
+    (cond
+      (<= n 0) acc
+      :else (go-strings-repeat-loop s (- n 1) (str acc s)))))
+
+(define
+  go-strings-count
+  (fn (args)
+    (cond
+      (not (= (len args) 2))
+      (list :eval-error :strings-count-arity (len args))
+      :else
+      (let ((s (first args)) (sub (nth args 1)))
+        (cond
+          (not (string? s)) (list :eval-error :strings-not-string s)
+          (not (string? sub)) (list :eval-error :strings-not-string sub)
+          :else (go-strings-count-loop s sub 0 0))))))
+
+(define
+  go-strings-count-loop
+  (fn (s sub start acc)
+    (let ((idx (go-strings-index-loop s sub start)))
+      (cond
+        (< idx 0) acc
+        :else
+        (go-strings-count-loop s sub (+ idx (max 1 (len sub))) (+ acc 1))))))
+
+(define
+  go-strings-join
+  (fn (args)
+    (cond
+      (not (= (len args) 2))
+      (list :eval-error :strings-join-arity (len args))
+      :else
+      (let ((sep (nth args 1)) (xs (first args)))
+        (cond
+          (not (string? sep)) (list :eval-error :strings-not-string sep)
+          (not (and (list? xs) (= (first xs) :go-slice)))
+          (list :eval-error :strings-join-not-slice xs)
+          :else (go-strings-join-loop (nth xs 1) sep ""))))))
+
+(define
+  go-strings-join-loop
+  (fn (xs sep acc)
+    (cond
+      (= (len xs) 0) acc
+      (= (len acc) 0) (go-strings-join-loop (rest xs) sep (first xs))
+      :else
+      (go-strings-join-loop (rest xs) sep (str acc sep (first xs))))))
+
+;; ── case conversion ──────────────────────────────────────────────
+
+(define
+  go-strings-char-to-upper
+  (fn (c)
+    (cond
+      (and (>= c "a") (<= c "z"))
+      ;; ASCII uppercase shift: 'a' is 0x61, 'A' is 0x41 → diff 0x20.
+      ;; SX has no charcode primitive, so use a char-pair table.
+      (go-strings-letter-toggle c true)
+      :else c)))
+
+(define
+  go-strings-char-to-lower
+  (fn (c)
+    (cond
+      (and (>= c "A") (<= c "Z"))
+      (go-strings-letter-toggle c false)
+      :else c)))
+
+(define
+  go-strings-letter-toggle
+  ;; Toggle a single ASCII letter's case via direct mapping.
+  ;; `to-upper?` true means input is lowercase, output uppercase.
+  (fn (c to-upper?)
+    (cond
+      to-upper?
+      (cond
+        (= c "a") "A" (= c "b") "B" (= c "c") "C" (= c "d") "D"
+        (= c "e") "E" (= c "f") "F" (= c "g") "G" (= c "h") "H"
+        (= c "i") "I" (= c "j") "J" (= c "k") "K" (= c "l") "L"
+        (= c "m") "M" (= c "n") "N" (= c "o") "O" (= c "p") "P"
+        (= c "q") "Q" (= c "r") "R" (= c "s") "S" (= c "t") "T"
+        (= c "u") "U" (= c "v") "V" (= c "w") "W" (= c "x") "X"
+        (= c "y") "Y" (= c "z") "Z" :else c)
+      :else
+      (cond
+        (= c "A") "a" (= c "B") "b" (= c "C") "c" (= c "D") "d"
+        (= c "E") "e" (= c "F") "f" (= c "G") "g" (= c "H") "h"
+        (= c "I") "i" (= c "J") "j" (= c "K") "k" (= c "L") "l"
+        (= c "M") "m" (= c "N") "n" (= c "O") "o" (= c "P") "p"
+        (= c "Q") "q" (= c "R") "r" (= c "S") "s" (= c "T") "t"
+        (= c "U") "u" (= c "V") "v" (= c "W") "w" (= c "X") "x"
+        (= c "Y") "y" (= c "Z") "z" :else c))))
+
+(define
+  go-strings-map-chars
+  (fn (s i acc char-fn)
+    (cond
+      (>= i (len s)) acc
+      :else
+      (go-strings-map-chars s (+ i 1) (str acc (char-fn (nth s i))) char-fn))))
+
+(define
+  go-strings-to-upper
+  (fn (args)
+    (cond
+      (not (= (len args) 1))
+      (list :eval-error :strings-toupper-arity (len args))
+      :else
+      (let ((s (first args)))
+        (cond
+          (not (string? s)) (list :eval-error :strings-not-string s)
+          :else (go-strings-map-chars s 0 "" go-strings-char-to-upper))))))
+
+(define
+  go-strings-to-lower
+  (fn (args)
+    (cond
+      (not (= (len args) 1))
+      (list :eval-error :strings-tolower-arity (len args))
+      :else
+      (let ((s (first args)))
+        (cond
+          (not (string? s)) (list :eval-error :strings-not-string s)
+          :else (go-strings-map-chars s 0 "" go-strings-char-to-lower))))))
+
+;; ── TrimSpace ────────────────────────────────────────────────────
+
+(define
+  go-strings-is-space?
+  (fn (c)
+    (or (= c " ") (= c "\t") (= c "\n") (= c "\r"))))
+
+(define
+  go-strings-trim-left
+  (fn (s i)
+    (cond
+      (>= i (len s)) i
+      (go-strings-is-space? (nth s i)) (go-strings-trim-left s (+ i 1))
+      :else i)))
+
+(define
+  go-strings-trim-right
+  (fn (s end)
+    (cond
+      (<= end 0) 0
+      (go-strings-is-space? (nth s (- end 1))) (go-strings-trim-right s (- end 1))
+      :else end)))
+
+(define
+  go-strings-substr
+  ;; Substring [lo, hi) — naive but predictable.
+  (fn (s lo hi)
+    (cond
+      (>= lo hi) ""
+      :else
+      (go-strings-substr-loop s lo hi ""))))
+
+(define
+  go-strings-substr-loop
+  (fn (s i hi acc)
+    (cond
+      (>= i hi) acc
+      :else (go-strings-substr-loop s (+ i 1) hi (str acc (nth s i))))))
+
+(define
+  go-strings-trim-space
+  (fn (args)
+    (cond
+      (not (= (len args) 1))
+      (list :eval-error :strings-trimspace-arity (len args))
+      :else
+      (let ((s (first args)))
+        (cond
+          (not (string? s)) (list :eval-error :strings-not-string s)
+          :else
+          (let ((lo (go-strings-trim-left s 0)))
+            (let ((hi (go-strings-trim-right s (len s))))
+              (go-strings-substr s lo hi))))))))
+
+;; ── Split ────────────────────────────────────────────────────────
+
+(define
+  go-strings-split
+  (fn (args)
+    (cond
+      (not (= (len args) 2))
+      (list :eval-error :strings-split-arity (len args))
+      :else
+      (let ((s (first args)) (sep (nth args 1)))
+        (cond
+          (not (string? s)) (list :eval-error :strings-not-string s)
+          (not (string? sep)) (list :eval-error :strings-not-string sep)
+          (= (len sep) 0)
+          ;; Empty separator: real Go splits to all chars; v0 keeps
+          ;; behaviour simple — single-element slice.
+          (list :go-slice (list s))
+          :else
+          (list :go-slice (go-strings-split-loop s sep 0 (list))))))))
+
+(define
+  go-strings-split-loop
+  (fn (s sep start acc)
+    (let ((idx (go-strings-index-loop s sep start)))
+      (cond
+        (< idx 0)
+        (go-strings-split-finalize acc (go-strings-substr s start (len s)))
+        :else
+        (go-strings-split-loop s sep (+ idx (len sep))
+          (go-strings-split-finalize acc
+            (go-strings-substr s start idx)))))))
+
+(define
+  go-strings-split-finalize
+  ;; Append a piece to acc, growing the list in order.
+  (fn (acc piece)
+    (cond
+      (= (len acc) 0) (list piece)
+      :else (go-name-concat acc (list piece)))))
+
+;; ── Replace ──────────────────────────────────────────────────────
+
+(define
+  go-strings-replace
+  ;; Replace(s, old, new, n). n < 0 = all.
+  (fn (args)
+    (cond
+      (not (= (len args) 4))
+      (list :eval-error :strings-replace-arity (len args))
+      :else
+      (let ((s (first args)) (old (nth args 1))
+            (newv (nth args 2)) (n (nth args 3)))
+        (cond
+          (not (string? s)) (list :eval-error :strings-not-string s)
+          (not (string? old)) (list :eval-error :strings-not-string old)
+          (not (string? newv)) (list :eval-error :strings-not-string newv)
+          (= (len old) 0) s
+          :else (go-strings-replace-loop s old newv n 0 ""))))))
+
+(define
+  go-strings-replace-loop
+  (fn (s old newv n start acc)
+    (let ((idx (go-strings-index-loop s old start)))
+      (cond
+        (or (< idx 0) (= n 0))
+        (str acc (go-strings-substr s start (len s)))
+        :else
+        (go-strings-replace-loop s old newv
+          (cond (< n 0) -1 :else (- n 1))
+          (+ idx (len old))
+          (str acc (go-strings-substr s start idx) newv))))))
+
+;; ── go-std-strings package value ─────────────────────────────────
+
+(define
+  go-std-strings
+  (list :go-package "strings"
+    (list
+      (list "Contains"  (list :go-builtin-fn go-strings-contains))
+      (list "HasPrefix" (list :go-builtin-fn go-strings-has-prefix))
+      (list "HasSuffix" (list :go-builtin-fn go-strings-has-suffix))
+      (list "Index"     (list :go-builtin-fn go-strings-index))
+      (list "Count"     (list :go-builtin-fn go-strings-count))
+      (list "Repeat"    (list :go-builtin-fn go-strings-repeat))
+      (list "Join"      (list :go-builtin-fn go-strings-join))
+      (list "ToUpper"   (list :go-builtin-fn go-strings-to-upper))
+      (list "ToLower"   (list :go-builtin-fn go-strings-to-lower))
+      (list "TrimSpace" (list :go-builtin-fn go-strings-trim-space))
+      (list "Split"     (list :go-builtin-fn go-strings-split))
+      (list "Replace"   (list :go-builtin-fn go-strings-replace)))))

lib/go/tests/e2e.sx

@@ -0,0 +1,186 @@
+;; Go end-to-end tests — complete programs exercising lex+parse+
+;; types+eval+sched+stdlib together. Each test runs a multi-line Go
+;; program and inspects the final env.
+
+(define go-e2e-test-count 0)
+(define go-e2e-test-pass 0)
+(define go-e2e-test-fails (list))
+
+(define
+  go-e2e-test
+  (fn (name actual expected)
+    (set! go-e2e-test-count (+ go-e2e-test-count 1))
+    (if (= actual expected)
+      (set! go-e2e-test-pass (+ go-e2e-test-pass 1))
+      (append! go-e2e-test-fails
+        {:name name :expected expected :actual actual}))))
+
+(define
+  go-e2e-env
+  (go-env-extend
+    (go-env-extend go-env-builtins "strings" go-std-strings)
+    "strconv" go-std-strconv))
+
+(define
+  go-e2e-run
+  (fn (src-list)
+    (go-eval-program go-e2e-env (map go-parse src-list))))
+
+;; ── 1. Sieve via boolean slice (no modulo needed) ────────────────
+(go-e2e-test "e2e: sieve-of-Eratosthenes via boolean slice — count primes ≤ 30"
+  (let ((env (go-e2e-run
+              (list
+                ;; sieve[i] true means i is COMPOSITE (saves the
+                ;; default-bool initialisation for primes).
+                "sieve := []bool{false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false}"
+                "for p := 2; p < 31; p = p + 1 { if sieve[p] == false { for k := p + p; k < 31; k = k + p { sieve[k] = true } } }"
+                "count := 0"
+                "for i := 2; i < 31; i = i + 1 { if sieve[i] == false { count = count + 1 } }"))))
+    (go-env-lookup env "count"))
+  ;; primes ≤ 30: 2,3,5,7,11,13,17,19,23,29 = 10
+  10)
+
+;; ── 1b. Range-membership check (works without mod) ───────────────
+(go-e2e-test "e2e: linear search across slice of strings"
+  (let ((env (go-e2e-run
+              (list
+                "words := []string{\"apple\", \"banana\", \"cherry\", \"date\"}"
+                "func indexOf(xs []string, target string) int { for i, v := range xs { if v == target { return i } } ; return -1 }"
+                "i := indexOf(words, \"cherry\")"
+                "missing := indexOf(words, \"xyz\")"))))
+    (list (go-env-lookup env "i") (go-env-lookup env "missing")))
+  (list 2 -1))
+
+;; ── 2. Reverse a slice ───────────────────────────────────────────
+(go-e2e-test "e2e: reverse a slice of ints"
+  (let ((env (go-e2e-run
+              (list
+                "func reverse(xs []int) []int { r := []int{} ; for i := len(xs) - 1; i >= 0; i = i - 1 { r = append(r, xs[i]) } ; return r }"
+                "out := reverse([]int{1, 2, 3, 4, 5})"))))
+    (go-env-lookup env "out"))
+  (list :go-slice (list 5 4 3 2 1)))
+
+;; ── 3. Fibonacci (recursive) ─────────────────────────────────────
+(go-e2e-test "e2e: fib(10) = 55"
+  (let ((env (go-e2e-run
+              (list
+                "func fib(n int) int { if n < 2 { return n } ; return fib(n-1) + fib(n-2) }"
+                "r := fib(10)"))))
+    (go-env-lookup env "r"))
+  55)
+
+;; ── 4. Sum-of-squares via Map+Reduce ─────────────────────────────
+(go-e2e-test "e2e: sum-of-squares 1..5 via Map+Reduce"
+  (let ((env (go-e2e-run
+              (list
+                "func Map[T any, U any](xs []T, f func(T) U) []U { r := []int{} ; for i, v := range xs { r = append(r, f(v)) } ; return r }"
+                "func Reduce[T any, U any](xs []T, seed U, f func(U, T) U) U { acc := seed ; for i, v := range xs { acc = f(acc, v) } ; return acc }"
+                "func sq(x int) int { return x * x }"
+                "func add(a int, b int) int { return a + b }"
+                "squares := Map([]int{1, 2, 3, 4, 5}, sq)"
+                "total := Reduce(squares, 0, add)"))))
+    (go-env-lookup env "total"))
+  ;; 1 + 4 + 9 + 16 + 25 = 55
+  55)
+
+;; ── 5. Word frequency counter ────────────────────────────────────
+(go-e2e-test "e2e: word-frequency over a sentence"
+  (let ((env (go-e2e-run
+              (list
+                "text := \"the quick brown fox jumps over the lazy dog the\""
+                "words := strings.Split(text, \" \")"
+                "counts := map[string]int{}"
+                "for i, w := range words { counts[w] = counts[w] + 1 }"
+                "the_count := counts[\"the\"]"
+                "fox_count := counts[\"fox\"]"
+                "dog_count := counts[\"dog\"]"))))
+    (list (go-env-lookup env "the_count")
+          (go-env-lookup env "fox_count")
+          (go-env-lookup env "dog_count")))
+  (list 3 1 1))
+
+;; ── 6. Pipeline via channels ─────────────────────────────────────
+(go-e2e-test "e2e: pipeline — generate, square, sum"
+  (let ((env (go-e2e-run
+              (list
+                "func gen(c chan int, n int) { for i := 1; i <= n; i = i + 1 { c <- i } ; close(c) }"
+                "func sq(in chan int, out chan int) { for v := range in { out <- v * v } ; close(out) }"
+                "src := make()"
+                "sqs := make()"
+                "go gen(src, 4)"
+                "go sq(src, sqs)"
+                "total := 0"
+                "for v := range sqs { total = total + v }"))))
+    (go-env-lookup env "total"))
+  ;; 1+4+9+16 = 30
+  30)
+
+;; ── 7. Worker pool draining a job channel ────────────────────────
+(go-e2e-test "e2e: worker pool — sum of doubled jobs"
+  (let ((env (go-e2e-run
+              (list
+                "func worker(jobs chan int, results chan int) { for j := range jobs { results <- j * 2 } }"
+                "jobs := make()"
+                "results := make()"
+                "jobs <- 10 ; jobs <- 20 ; jobs <- 30"
+                "close(jobs)"
+                "go worker(jobs, results)"
+                "close(results)"
+                "sum := 0"
+                "for r := range results { sum = sum + r }"))))
+    (go-env-lookup env "sum"))
+  ;; 20 + 40 + 60 = 120
+  120)
+
+;; ── 8. Bubble sort ───────────────────────────────────────────────
+(go-e2e-test "e2e: bubble sort ascending"
+  (let ((env (go-e2e-run
+              (list
+                "func bubble(xs []int) []int { n := len(xs) ; for i := 0; i < n; i = i + 1 { for j := 0; j < n - 1; j = j + 1 { if xs[j] > xs[j+1] { tmp := xs[j] ; xs[j] = xs[j+1] ; xs[j+1] = tmp } } } ; return xs }"
+                "out := bubble([]int{3, 1, 4, 1, 5, 9, 2, 6})"))))
+    (go-env-lookup env "out"))
+  (list :go-slice (list 1 1 2 3 4 5 6 9)))
+
+;; ── 9. String reverse using strings.Split + reverse + Join ──────
+(go-e2e-test "e2e: reverse words in a sentence"
+  (let ((env (go-e2e-run
+              (list
+                "func rev(xs []string) []string { r := []string{} ; for i := len(xs) - 1; i >= 0; i = i - 1 { r = append(r, xs[i]) } ; return r }"
+                "text := \"go on sx\""
+                "out := strings.Join(rev(strings.Split(text, \" \")), \"-\")"))))
+    (go-env-lookup env "out"))
+  "sx-on-go")
+
+;; ── 10. Counting occurrences via Filter ──────────────────────────
+(go-e2e-test "e2e: count even numbers via Filter+len"
+  (let ((env (go-e2e-run
+              (list
+                "func Filter[T any](xs []T, p func(T) bool) []T { r := []int{} ; for i, v := range xs { if p(v) { r = append(r, v) } } ; return r }"
+                "func gt5(x int) bool { return x > 5 }"
+                "n := len(Filter([]int{1, 2, 6, 3, 7, 8, 4, 9}, gt5))"))))
+    (go-env-lookup env "n"))
+  ;; gt5: 6,7,8,9 = 4
+  4)
+
+;; ── 11. Recursive ackermann (small inputs) ───────────────────────
+(go-e2e-test "e2e: ackermann(2, 3) = 9"
+  (let ((env (go-e2e-run
+              (list
+                "func ack(m int, n int) int { if m == 0 { return n + 1 } ; if n == 0 { return ack(m - 1, 1) } ; return ack(m - 1, ack(m, n - 1)) }"
+                "r := ack(2, 3)"))))
+    (go-env-lookup env "r"))
+  9)
+
+;; ── 12. Defer + recover smoke test ───────────────────────────────
+(go-e2e-test "e2e: defer + recover in real-fn flow"
+  (let ((env (go-e2e-run
+              (list
+                "func safeDivide(a int, b int) int { defer recover() ; if b == 0 { panic(\"div by zero\") } ; return a / b }"
+                "r := safeDivide(10, 0)"
+                "after := 99"))))
+    (go-env-lookup env "after"))
+  99)
+
+(define
+  go-e2e-test-summary
+  (str "e2e " go-e2e-test-pass "/" go-e2e-test-count))

lib/go/tests/eval.sx

@@ -0,0 +1,667 @@
+;; Go evaluator tests.
+
+(define go-eval-test-count 0)
+(define go-eval-test-pass 0)
+(define go-eval-test-fails (list))
+
+(define
+  go-eval-test
+  (fn
+    (name actual expected)
+    (set! go-eval-test-count (+ go-eval-test-count 1))
+    (if
+      (= actual expected)
+      (set! go-eval-test-pass (+ go-eval-test-pass 1))
+      (append! go-eval-test-fails {:name name :expected expected :actual actual}))))
+
+(define gtev (fn (env src) (go-eval env (go-parse src))))
+
+;; ── env ──────────────────────────────────────────────────────────
+(go-eval-test
+  "env: empty lookup returns nil"
+  (go-env-lookup go-env-empty "x")
+  nil)
+
+(go-eval-test
+  "env: extend then lookup"
+  (go-env-lookup (go-env-extend go-env-empty "x" 42) "x")
+  42)
+
+;; ── literals ────────────────────────────────────────────────────
+(go-eval-test "lit: 42 → 42" (gtev go-env-empty "42") 42)
+
+(go-eval-test "lit: 0 → 0" (gtev go-env-empty "0") 0)
+
+(go-eval-test "lit: 0xFF → 255" (gtev go-env-empty "0xFF") 255)
+
+(go-eval-test "lit: 0b1010 → 10" (gtev go-env-empty "0b1010") 10)
+
+(go-eval-test "lit: 0o17 → 15" (gtev go-env-empty "0o17") 15)
+
+(go-eval-test
+  "lit: underscore separator 1_000 → 1000"
+  (gtev go-env-empty "1_000")
+  1000)
+
+(go-eval-test "lit: string" (gtev go-env-empty "\"hello\"") "hello")
+
+;; ── predeclared ─────────────────────────────────────────────────
+(go-eval-test "var: true" (gtev go-env-empty "true") true)
+(go-eval-test "var: false" (gtev go-env-empty "false") false)
+(go-eval-test "var: nil" (gtev go-env-empty "nil") nil)
+
+;; ── variable lookup ─────────────────────────────────────────────
+(go-eval-test
+  "var: bound x → 5"
+  (go-eval (go-env-extend go-env-empty "x" 5) (go-parse "x"))
+  5)
+
+(go-eval-test
+  "var: unbound y → :eval-error"
+  (gtev go-env-empty "y")
+  (list :eval-error :unbound "y"))
+
+;; ── binary ops ─────────────────────────────────────────────────
+(go-eval-test "binop: 1 + 2 → 3" (gtev go-env-empty "1 + 2") 3)
+(go-eval-test "binop: 10 - 4 → 6" (gtev go-env-empty "10 - 4") 6)
+(go-eval-test "binop: 3 * 7 → 21" (gtev go-env-empty "3 * 7") 21)
+(go-eval-test "binop: 42 / 7 → 6" (gtev go-env-empty "42 / 7") 6)
+(go-eval-test
+  "binop: 2 + 3 * 4 → 14 (prec)"
+  (gtev go-env-empty "2 + 3 * 4")
+  14)
+(go-eval-test
+  "binop: a + b uses env"
+  (go-eval
+    (go-env-extend (go-env-extend go-env-empty "a" 3) "b" 4)
+    (go-parse "a + b"))
+  7)
+
+(go-eval-test "binop: 1 < 2 → true" (gtev go-env-empty "1 < 2") true)
+(go-eval-test "binop: 5 == 5 → true" (gtev go-env-empty "5 == 5") true)
+(go-eval-test "binop: 5 != 5 → false" (gtev go-env-empty "5 != 5") false)
+(go-eval-test
+  "binop: true && false → false"
+  (gtev go-env-empty "true && false")
+  false)
+(go-eval-test
+  "binop: false || true → true"
+  (gtev go-env-empty "false || true")
+  true)
+
+;; ── report ──────────────────────────────────────────────────────
+(go-eval-test
+  "var-decl: var x = 5 — env has x=5"
+  (go-env-lookup
+    (go-eval-program go-env-empty (list (go-parse "var x = 5")))
+    "x")
+  5)
+
+(go-eval-test
+  "short-decl: a, b := 3, 4 — env has both"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "a, b := 3, 4")))))
+    (list (go-env-lookup env "a") (go-env-lookup env "b")))
+  (list 3 4))
+
+(go-eval-test
+  "assign: x = 5 then x → 5"
+  (let
+    ((env (go-eval-program (go-env-extend go-env-empty "x" 1) (list (go-parse "x = 5")))))
+    (go-env-lookup env "x"))
+  5)
+
+(go-eval-test
+  "if: true branch evaluates"
+  (let
+    ((env (go-eval-program (go-env-extend go-env-empty "x" 0) (list (go-parse "if true { x = 1 }")))))
+    (go-env-lookup env "x"))
+  1)
+
+(go-eval-test
+  "if-else: false → else branch"
+  (let
+    ((env (go-eval-program (go-env-extend go-env-empty "x" 0) (list (go-parse "if false { x = 1 } else { x = 2 }")))))
+    (go-env-lookup env "x"))
+  2)
+
+(go-eval-test
+  "fn: define + call — double(7) = 14"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "func double(x int) int { return x * 2 }")))))
+    (go-eval env (go-parse "double(7)")))
+  14)
+
+(go-eval-test
+  "fn: add(2, 3) = 5"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "func add(x, y int) int { return x + y }")))))
+    (go-eval env (go-parse "add(2, 3)")))
+  5)
+
+(go-eval-test
+  "fn: recursive fib(5) = 5"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "func fib(n int) int { if n < 2 { return n } return fib(n-1) + fib(n-2) }")))))
+    (go-eval env (go-parse "fib(5)")))
+  5)
+
+(go-eval-test
+  "for: count to 10 with sum"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "var sum = 0") (go-parse "for i := 0; i < 10; i++ { sum = sum + i }")))))
+    (go-env-lookup env "sum"))
+  45)
+
+(go-eval-test
+  "inc-dec: x++ updates env"
+  (let
+    ((env (go-eval-program (go-env-extend go-env-empty "x" 5) (list (go-parse "x++")))))
+    (go-env-lookup env "x"))
+  6)
+
+(go-eval-test
+  "inc-dec: x-- updates env"
+  (let
+    ((env (go-eval-program (go-env-extend go-env-empty "x" 5) (list (go-parse "x--")))))
+    (go-env-lookup env "x"))
+  4)
+
+(go-eval-test
+  "for: break exits the loop"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "var i = 0") (go-parse "for i < 100 { if i == 5 { break } ; i++ }")))))
+    (go-env-lookup env "i"))
+  5)
+
+(go-eval-test
+  "for: continue skips body but runs post"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "var sum = 0") (go-parse "for i := 0; i < 5; i++ { if i == 2 { continue } ; sum = sum + i }")))))
+    (go-env-lookup env "sum"))
+  8)
+
+(go-eval-test
+  "for: infinite + break with sum"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "var s = 0") (go-parse "var i = 1") (go-parse "for { if i > 4 { break } ; s = s + i ; i++ }")))))
+    (go-env-lookup env "s"))
+  10)
+
+(go-eval-test
+  "fn: iterative factorial via for-loop"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "func fact(n int) int { r := 1 ; for i := 2 ; i <= n ; i++ { r = r * i } ; return r }")))))
+    (go-eval env (go-parse "fact(5)")))
+  120)
+
+(go-eval-test
+  "slice: []int{1,2,3} → :go-slice"
+  (gtev go-env-empty "[]int{1, 2, 3}")
+  (list :go-slice (list 1 2 3)))
+
+(go-eval-test
+  "index: a[0] = 10, a[2] = 30"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "a := []int{10, 20, 30}")))))
+    (list (go-eval env (go-parse "a[0]")) (go-eval env (go-parse "a[2]"))))
+  (list 10 30))
+
+(go-eval-test
+  "index: out-of-range error"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "a := []int{1, 2}")))))
+    (go-eval env (go-parse "a[5]")))
+  (list :eval-error :index-out-of-range 5 2))
+
+(go-eval-test
+  "builtin: len(slice) = 3"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "a := []int{1, 2, 3}")))))
+    (go-eval env (go-parse "len(a)")))
+  3)
+
+(go-eval-test
+  "builtin: len(string)"
+  (go-eval go-env-builtins (go-parse "len(\"hello\")"))
+  5)
+
+(go-eval-test
+  "builtin: append(a, 4, 5)"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "a := []int{1, 2, 3}")))))
+    (go-eval env (go-parse "append(a, 4, 5)")))
+  (list
+    :go-slice (list 1 2 3 4 5)))
+
+(go-eval-test
+  "slice expr: a[1:3]"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "a := []int{10, 20, 30, 40}")))))
+    (go-eval env (go-parse "a[1:3]")))
+  (list :go-slice (list 20 30)))
+
+(go-eval-test
+  "slice expr: a[:2] (omitted low)"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "a := []int{1, 2, 3, 4}")))))
+    (go-eval env (go-parse "a[:2]")))
+  (list :go-slice (list 1 2)))
+
+(go-eval-test
+  "slice expr: a[2:] (omitted high)"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "a := []int{1, 2, 3, 4}")))))
+    (go-eval env (go-parse "a[2:]")))
+  (list :go-slice (list 3 4)))
+
+(go-eval-test
+  "fn: sum slice via for-loop with len + index"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "a := []int{1, 2, 3, 4, 5}") (go-parse "sum := 0") (go-parse "for i := 0; i < len(a); i++ { sum = sum + a[i] }")))))
+    (go-env-lookup env "sum"))
+  15)
+
+(go-eval-test
+  "map: map[string]int{...} → :go-map"
+  (gtev go-env-empty "map[string]int{\"a\": 1, \"b\": 2}")
+  (list :go-map (list (list "a" 1) (list "b" 2))))
+
+(go-eval-test
+  "map: m[\"a\"] → 1"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "m := map[string]int{\"a\": 1, \"b\": 2}")))))
+    (go-eval env (go-parse "m[\"a\"]")))
+  1)
+
+(go-eval-test
+  "map: missing key → nil (v0 stand-in for zero value)"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "m := map[string]int{\"a\": 1}")))))
+    (go-eval env (go-parse "m[\"missing\"]")))
+  nil)
+
+(go-eval-test
+  "map: len(m) = 2"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "m := map[string]int{\"a\": 1, \"b\": 2}")))))
+    (go-eval env (go-parse "len(m)")))
+  2)
+
+(go-eval-test
+  "map: index-assign updates existing key"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "m := map[string]int{\"a\": 1}") (go-parse "m[\"a\"] = 99")))))
+    (go-eval env (go-parse "m[\"a\"]")))
+  99)
+
+(go-eval-test
+  "map: index-assign adds new key"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "m := map[string]int{}") (go-parse "m[\"new\"] = 7")))))
+    (go-eval env (go-parse "m[\"new\"]")))
+  7)
+
+(go-eval-test
+  "slice: index-assign a[0] = 99"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "a := []int{10, 20, 30}") (go-parse "a[0] = 99")))))
+    (go-eval env (go-parse "a[0]")))
+  99)
+
+(go-eval-test
+  "map: word count via loop"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "words := []string{\"a\", \"b\", \"a\", \"c\", \"a\"}") (go-parse "counts := map[string]int{}") (go-parse "for i := 0; i < len(words); i++ { counts[words[i]] = counts[words[i]] + 1 }")))))
+    (go-eval env (go-parse "counts[\"a\"]")))
+  3)
+
+(go-eval-test
+  "type-decl: registers struct field names"
+  (go-env-lookup
+    (go-eval-program
+      go-env-empty
+      (list (go-parse "type Point struct { x, y int }")))
+    "Point")
+  (list :go-struct-type (list "x" "y")))
+
+(go-eval-test
+  "struct: positional composite Point{1, 2}"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "type Point struct { x, y int }")))))
+    (go-eval env (go-parse "Point{1, 2}")))
+  (list
+    :go-struct "Point"
+    (list (list "x" 1) (list "y" 2))))
+
+(go-eval-test
+  "struct: keyed composite Point{x: 5, y: 10}"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "type Point struct { x, y int }")))))
+    (go-eval env (go-parse "Point{x: 5, y: 10}")))
+  (list
+    :go-struct "Point"
+    (list (list "x" 5) (list "y" 10))))
+
+(go-eval-test
+  "struct: selector p.x = 1"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "type Point struct { x, y int }") (go-parse "p := Point{1, 2}")))))
+    (go-eval env (go-parse "p.x")))
+  1)
+
+(go-eval-test
+  "struct: selector p.y = 2"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "type Point struct { x, y int }") (go-parse "p := Point{1, 2}")))))
+    (go-eval env (go-parse "p.y")))
+  2)
+
+(go-eval-test
+  "struct: selector-assign p.x = 99"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "type Point struct { x, y int }") (go-parse "p := Point{1, 2}") (go-parse "p.x = 99")))))
+    (go-eval env (go-parse "p.x")))
+  99)
+
+(go-eval-test
+  "struct: positional arity-mismatch"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "type Point struct { x, y int }")))))
+    (go-eval env (go-parse "Point{1}")))
+  (list :eval-error :struct-arity-mismatch "Point" 2 1))
+
+(go-eval-test
+  "struct: function takes/returns struct"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "type Point struct { x, y int }") (go-parse "func add(a, b Point) Point { return Point{a.x + b.x, a.y + b.y} }")))))
+    (go-eval env (go-parse "add(Point{1, 2}, Point{3, 4})")))
+  (list
+    :go-struct "Point"
+    (list (list "x" 4) (list "y" 6))))
+
+(go-eval-test
+  "method: p.Sum() = 3"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "type Point struct { x, y int }") (go-parse "func (p Point) Sum() int { return p.x + p.y }") (go-parse "p := Point{1, 2}")))))
+    (go-eval env (go-parse "p.Sum()")))
+  3)
+
+(go-eval-test
+  "method: p.Add(5) = 6 (with arg)"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "type Point struct { x, y int }") (go-parse "func (p Point) Add(d int) int { return p.x + d }") (go-parse "p := Point{1, 2}")))))
+    (go-eval env (go-parse "p.Add(5)")))
+  6)
+
+(go-eval-test
+  "method: pointer receiver works value-style in v0"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "type Point struct { x, y int }") (go-parse "func (p *Point) GetX() int { return p.x }") (go-parse "p := Point{1, 2}")))))
+    (go-eval env (go-parse "p.GetX()")))
+  1)
+
+(go-eval-test
+  "method: missing method → :no-such-method"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "type Point struct { x, y int }") (go-parse "p := Point{1, 2}")))))
+    (go-eval env (go-parse "p.Ghost()")))
+  (list :eval-error :no-such-method "Point" "Ghost"))
+
+(go-eval-test
+  "unary: -x"
+  (go-eval (go-env-extend go-env-empty "x" 5) (go-parse "-x"))
+  -5)
+
+(go-eval-test "unary: !true → false" (gtev go-env-empty "!true") false)
+
+(go-eval-test "unary: !false → true" (gtev go-env-empty "!false") true)
+
+(go-eval-test
+  "unary: -3 + 5 = 2 (unary binds tighter)"
+  (gtev go-env-empty "-3 + 5")
+  2)
+
+(go-eval-test
+  "e2e: count odd numbers in 1..10 = 5"
+  (let
+    ((env (go-eval-program go-env-empty
+            (list (go-parse "odds := 0")
+                  (go-parse "i := 1")
+                  (go-parse "for i <= 10 { odds = odds + 1; i = i + 2 }")))))
+    (go-env-lookup env "odds"))
+  5)
+
+(go-eval-test
+  "e2e: factorial via method on Counter"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "type Acc struct { v int }") (go-parse "func (a Acc) Mul(x int) Acc { return Acc{a.v * x} }") (go-parse "a := Acc{1}") (go-parse "for i := 1; i <= 5; i++ { a = a.Mul(i) }")))))
+    (go-eval env (go-parse "a.v")))
+  120)
+
+(go-eval-test
+  "e2e: recursive fibonacci fib(10) = 55"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "func fib(n int) int { if n < 2 { return n } return fib(n-1) + fib(n-2) }")))))
+    (go-eval env (go-parse "fib(10)")))
+  55)
+
+(go-eval-test
+  "e2e: struct + method + iterative loop"
+  (let
+    ((env (go-eval-program go-env-empty (list (go-parse "type Counter struct { n int }") (go-parse "func (c Counter) Bump() Counter { return Counter{c.n + 1} }") (go-parse "c := Counter{0}") (go-parse "for i := 0; i < 7; i++ { c = c.Bump() }")))))
+    (go-eval env (go-parse "c.n")))
+  7)
+
+(go-eval-test
+  "e2e: linear search returns index"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func find(a []int, x int) int { for i := 0; i < len(a); i++ { if a[i] == x { return i } } ; return -1 }") (go-parse "nums := []int{10, 20, 30, 40}")))))
+    (go-eval env (go-parse "find(nums, 30)")))
+  2)
+
+(go-eval-test
+  "e2e: linear search returns -1 when missing"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func find(a []int, x int) int { for i := 0; i < len(a); i++ { if a[i] == x { return i } } ; return -1 }") (go-parse "nums := []int{10, 20, 30}")))))
+    (go-eval env (go-parse "find(nums, 99)")))
+  -1)
+
+(go-eval-test
+  "defer: single defer runs after surrounding fn body returns"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()") (go-parse "func push2(c chan int) { c <- 2 }") (go-parse "func run(c chan int) { defer push2(c) ; c <- 1 }") (go-parse "run(ch)") (go-parse "first := <-ch") (go-parse "second := <-ch")))))
+    (list (go-env-lookup env "first") (go-env-lookup env "second")))
+  (list 1 2))
+
+(go-eval-test
+  "defer: multiple defers run LIFO"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()") (go-parse "func p2(c chan int) { c <- 2 }") (go-parse "func p3(c chan int) { c <- 3 }") (go-parse "func run(c chan int) { defer p2(c) ; defer p3(c) ; c <- 1 }") (go-parse "run(ch)") (go-parse "a := <-ch") (go-parse "b := <-ch") (go-parse "d := <-ch")))))
+    (list
+      (go-env-lookup env "a")
+      (go-env-lookup env "b")
+      (go-env-lookup env "d")))
+  (list 1 3 2))
+
+(go-eval-test
+  "defer: arguments are evaluated at defer-time (not call-time)"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()") (go-parse "func pushN(c chan int, v int) { c <- v }") (go-parse "func run(c chan int) { x := 7 ; defer pushN(c, x) ; x = 99 }") (go-parse "run(ch)") (go-parse "got := <-ch")))))
+    (go-env-lookup env "got"))
+  7)
+
+(go-eval-test
+  "defer: runs even when fn returns early via return"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()") (go-parse "func note(c chan int) { c <- 42 }") (go-parse "func run(c chan int) int { defer note(c) ; return 1 }") (go-parse "r := run(ch)") (go-parse "n := <-ch")))))
+    (list (go-env-lookup env "r") (go-env-lookup env "n")))
+  (list 1 42))
+
+(go-eval-test
+  "defer: stack is frame-local — outer defers don't run on inner return"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()") (go-parse "func push1(c chan int) { c <- 1 }") (go-parse "func push2(c chan int) { c <- 2 }") (go-parse "func inner(c chan int) { defer push2(c) }") (go-parse "func outer(c chan int) { defer push1(c) ; inner(c) }") (go-parse "outer(ch)") (go-parse "a := <-ch") (go-parse "b := <-ch")))))
+    (list (go-env-lookup env "a") (go-env-lookup env "b")))
+  (list 2 1))
+
+(go-eval-test
+  "defer: in a loop, all defers fire on fn return (not loop iter)"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()") (go-parse "func pushI(c chan int, v int) { c <- v }") (go-parse "func loop(c chan int) { for i := 0; i < 4; i = i + 1 { defer pushI(c, i) } }") (go-parse "loop(ch)") (go-parse "a := <-ch") (go-parse "b := <-ch") (go-parse "d := <-ch") (go-parse "e := <-ch")))))
+    (list
+      (go-env-lookup env "a")
+      (go-env-lookup env "b")
+      (go-env-lookup env "d")
+      (go-env-lookup env "e")))
+  (list 3 2 1 0))
+
+(go-eval-test
+  "panic: uncaught panic surfaces as (:go-panic V) from program"
+  (let
+    ((r (go-eval-program go-env-builtins (list (go-parse "panic(\"boom\")")))))
+    r)
+  (list :go-panic "boom"))
+
+(go-eval-test
+  "panic inside fn: surfaces from fn call too"
+  (let
+    ((r (go-eval-program go-env-builtins (list (go-parse "func boom() { panic(\"oops\") }") (go-parse "boom()")))))
+    r)
+  (list :go-panic "oops"))
+
+(go-eval-test
+  "recover: deferred recover swallows panic, fn returns normally"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func safe() { defer recover() ; panic(\"x\") }") (go-parse "safe()") (go-parse "after := 42")))))
+    (go-env-lookup env "after"))
+  42)
+
+(go-eval-test
+  "recover: deferred recover captures the panic value"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()") (go-parse "func grab(c chan int) { r := recover() ; c <- r }") (go-parse "func safe(c chan int) { defer grab(c) ; panic(99) }") (go-parse "safe(ch)") (go-parse "got := <-ch")))))
+    (go-env-lookup env "got"))
+  99)
+
+(go-eval-test
+  "panic: propagates through intermediate frames without defers"
+  (let
+    ((r (go-eval-program go-env-builtins (list (go-parse "func inner() { panic(\"deep\") }") (go-parse "func middle() { inner() }") (go-parse "func outer() { middle() }") (go-parse "outer()")))))
+    r)
+  (list :go-panic "deep"))
+
+(go-eval-test
+  "recover: middle-frame defer catches panic from deeper frame"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func inner() { panic(\"deep\") }") (go-parse "func middle() { inner() }") (go-parse "func outer() { defer recover() ; middle() }") (go-parse "outer()") (go-parse "after := 7")))))
+    (go-env-lookup env "after"))
+  7)
+
+(go-eval-test
+  "goroutine panic: surfaces synchronously back to spawner (v0)"
+  (let
+    ((r (go-eval-program go-env-builtins (list (go-parse "func boom() { panic(\"goroutine\") }") (go-parse "go boom()")))))
+    r)
+  (list :go-panic "goroutine"))
+
+(go-eval-test
+  "goroutine panic + spawner-defer-recover catches it (v0 sync)"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func boom() { panic(\"g\") }") (go-parse "func main() { defer recover() ; go boom() }") (go-parse "main()") (go-parse "after := 11")))))
+    (go-env-lookup env "after"))
+  11)
+
+(go-eval-test
+  "defer order with recover: all defers run, recover catches"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()") (go-parse "func p2(c chan int) { c <- 2 }") (go-parse "func rec(c chan int) { recover() ; c <- 7 }") (go-parse "func safe(c chan int) { defer p2(c) ; defer rec(c) ; panic(0) }") (go-parse "safe(ch)") (go-parse "a := <-ch") (go-parse "b := <-ch")))))
+    (list (go-env-lookup env "a") (go-env-lookup env "b")))
+  (list 7 2))
+
+(go-eval-test
+  "defer fires when fn panics (not just normal return)"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()") (go-parse "func note(c chan int) { c <- 5 }") (go-parse "func safe(c chan int) { defer note(c) ; defer recover() ; panic(\"!\") }") (go-parse "safe(ch)") (go-parse "got := <-ch")))))
+    (go-env-lookup env "got"))
+  5)
+
+(go-eval-test
+  "panic with nil value: still surfaces as (:go-panic nil)"
+  (let
+    ((r (go-eval-program go-env-builtins (list (go-parse "panic(nil)")))))
+    r)
+  (list :go-panic nil))
+
+(go-eval-test
+  "panic inside loop body: aborts loop + propagates"
+  (let
+    ((r (go-eval-program go-env-builtins (list (go-parse "func find(x int) { for i := 0; i < 10; i = i + 1 { if i == x { panic(i) } } }") (go-parse "find(3)")))))
+    r)
+  (list :go-panic 3))
+
+(go-eval-test
+  "defer in panicking fn: still runs even though no return reached"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()") (go-parse "func mark(c chan int) { c <- 8 }") (go-parse "func inner(c chan int) { defer mark(c) ; panic(\"!\") }") (go-parse "func outer(c chan int) { defer recover() ; inner(c) }") (go-parse "outer(ch)") (go-parse "got := <-ch")))))
+    (go-env-lookup env "got"))
+  8)
+
+(go-eval-test
+  "defer fn captures args by value, not reference (re-confirm)"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()") (go-parse "func pushN(c chan int, v int) { c <- v }") (go-parse "func run(c chan int) { defer recover() ; x := 5 ; defer pushN(c, x) ; x = 999 ; panic(\"k\") }") (go-parse "run(ch)") (go-parse "got := <-ch")))))
+    (go-env-lookup env "got"))
+  5)
+
+(go-eval-test
+  "generic: identity Id[T any](x) returns x at runtime"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func Id[T any](x T) T { return x }") (go-parse "r := Id(42)")))))
+    (go-env-lookup env "r"))
+  42)
+
+(go-eval-test
+  "generic: Id works with strings (type erasure)"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func Id[T any](x T) T { return x }") (go-parse "r := Id(\"hi\")")))))
+    (go-env-lookup env "r"))
+  "hi")
+
+(go-eval-test
+  "generic: Map[T, U] over []int with double — produces []int"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func Map[T any, U any](xs []T, f func(T) U) []U { r := []int{} ; for i, v := range xs { r = append(r, f(v)) } ; return r }") (go-parse "func dbl(x int) int { return x * 2 }") (go-parse "out := Map([]int{1, 2, 3}, dbl)") (go-parse "first := out[0]") (go-parse "second := out[1]") (go-parse "third := out[2]")))))
+    (list
+      (go-env-lookup env "first")
+      (go-env-lookup env "second")
+      (go-env-lookup env "third")))
+  (list 2 4 6))
+
+(go-eval-test
+  "generic: Filter[T any] keeps elements satisfying predicate"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func Filter[T any](xs []T, p func(T) bool) []T { r := []int{} ; for i, v := range xs { if p(v) { r = append(r, v) } } ; return r }") (go-parse "func gt3(x int) bool { return x > 3 }") (go-parse "out := Filter([]int{1, 2, 3, 4, 5, 6}, gt3)") (go-parse "n := len(out)") (go-parse "first := out[0]") (go-parse "last := out[2]")))))
+    (list
+      (go-env-lookup env "n")
+      (go-env-lookup env "first")
+      (go-env-lookup env "last")))
+  (list 3 4 6))
+
+(go-eval-test
+  "generic: Reduce[T, U] sums []int with seed 0"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func Reduce[T any, U any](xs []T, seed U, f func(U, T) U) U { acc := seed ; for i, v := range xs { acc = f(acc, v) } ; return acc }") (go-parse "func add(a int, b int) int { return a + b }") (go-parse "total := Reduce([]int{10, 20, 30, 40}, 0, add)")))))
+    (go-env-lookup env "total"))
+  100)
+
+(go-eval-test
+  "generic: First[T any]([]T) T returns element zero"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func First[T any](xs []T) T { return xs[0] }") (go-parse "v := First([]int{42, 99})")))))
+    (go-env-lookup env "v"))
+  42)
+
+(define
+  go-eval-test-summary
+  (str "eval " go-eval-test-pass "/" go-eval-test-count))

lib/go/tests/lex.sx

@@ -0,0 +1,339 @@
+;; Go tokenizer tests.
+
+(define go-test-count 0)
+(define go-test-pass 0)
+(define go-test-fails (list))
+
+(define gtok-type (fn (t) (get t :type)))
+(define gtok-value (fn (t) (get t :value)))
+(define tok-types (fn (src) (map gtok-type (go-tokenize src))))
+(define tok-values (fn (src) (map gtok-value (go-tokenize src))))
+
+(define
+  go-test
+  (fn
+    (name actual expected)
+    (set! go-test-count (+ go-test-count 1))
+    (if
+      (= actual expected)
+      (set! go-test-pass (+ go-test-pass 1))
+      (append! go-test-fails {:name name :expected expected :actual actual}))))
+
+;; ── empty / whitespace ────────────────────────────────────────────
+(go-test "empty source" (tok-types "") (list "eof"))
+(go-test "spaces only" (tok-types "   ") (list "eof"))
+(go-test "tabs only" (tok-types "\t\t") (list "eof"))
+(go-test
+  "newline only — no prior token, no ASI"
+  (tok-types "\n")
+  (list "eof"))
+
+;; ── identifiers ───────────────────────────────────────────────────
+(go-test "ident: simple" (tok-values "foo") (list "foo" "\n" nil))
+(go-test
+  "ident: underscore prefix"
+  (tok-values "_bar")
+  (list "_bar" "\n" nil))
+(go-test "ident: mixed case" (tok-values "fooBar") (list "fooBar" "\n" nil))
+(go-test "ident: with digits" (tok-values "x123") (list "x123" "\n" nil))
+(go-test "ident: type tag" (tok-types "foo") (list "ident" "semi" "eof"))
+
+;; ── keywords (all 25) ─────────────────────────────────────────────
+(go-test "kw: break" (tok-types "break") (list "keyword" "semi" "eof"))
+(go-test "kw: case" (tok-types "case") (list "keyword" "eof"))
+(go-test "kw: chan" (tok-types "chan") (list "keyword" "eof"))
+(go-test "kw: const" (tok-types "const") (list "keyword" "eof"))
+(go-test "kw: continue" (tok-types "continue") (list "keyword" "semi" "eof"))
+(go-test "kw: default" (tok-types "default") (list "keyword" "eof"))
+(go-test "kw: defer" (tok-types "defer") (list "keyword" "eof"))
+(go-test "kw: else" (tok-types "else") (list "keyword" "eof"))
+(go-test
+  "kw: fallthrough"
+  (tok-types "fallthrough")
+  (list "keyword" "semi" "eof"))
+(go-test "kw: for" (tok-types "for") (list "keyword" "eof"))
+(go-test "kw: func" (tok-types "func") (list "keyword" "eof"))
+(go-test "kw: go" (tok-types "go") (list "keyword" "eof"))
+(go-test "kw: goto" (tok-types "goto") (list "keyword" "eof"))
+(go-test "kw: if" (tok-types "if") (list "keyword" "eof"))
+(go-test "kw: import" (tok-types "import") (list "keyword" "eof"))
+(go-test "kw: interface" (tok-types "interface") (list "keyword" "eof"))
+(go-test "kw: map" (tok-types "map") (list "keyword" "eof"))
+(go-test "kw: package" (tok-types "package") (list "keyword" "eof"))
+(go-test "kw: range" (tok-types "range") (list "keyword" "eof"))
+(go-test "kw: return" (tok-types "return") (list "keyword" "semi" "eof"))
+(go-test "kw: select" (tok-types "select") (list "keyword" "eof"))
+(go-test "kw: struct" (tok-types "struct") (list "keyword" "eof"))
+(go-test "kw: switch" (tok-types "switch") (list "keyword" "eof"))
+(go-test "kw: type" (tok-types "type") (list "keyword" "eof"))
+(go-test "kw: var" (tok-types "var") (list "keyword" "eof"))
+
+;; ── integer literals — decimal ────────────────────────────────────
+(go-test "int: zero" (tok-values "0") (list "0" "\n" nil))
+(go-test "int: small" (tok-values "42") (list "42" "\n" nil))
+(go-test "int: bigger" (tok-values "123456") (list "123456" "\n" nil))
+(go-test "int: type" (tok-types "42") (list "int" "semi" "eof"))
+
+;; ── integer literals — prefixed + underscores ─────────────────────
+(go-test "int: hex lower" (tok-values "0x1f") (list "0x1f" "\n" nil))
+(go-test "int: hex upper-x" (tok-values "0X1F") (list "0X1F" "\n" nil))
+(go-test
+  "int: hex mixed digits"
+  (tok-values "0xDEADbeef")
+  (list "0xDEADbeef" "\n" nil))
+(go-test "int: binary lower" (tok-values "0b1010") (list "0b1010" "\n" nil))
+(go-test "int: binary upper" (tok-values "0B1101") (list "0B1101" "\n" nil))
+(go-test "int: octal modern" (tok-values "0o755") (list "0o755" "\n" nil))
+(go-test "int: octal upper" (tok-values "0O17") (list "0O17" "\n" nil))
+(go-test "int: octal legacy" (tok-values "0755") (list "0755" "\n" nil))
+(go-test "int: hex type" (tok-types "0x1F") (list "int" "semi" "eof"))
+(go-test "int: bin type" (tok-types "0b101") (list "int" "semi" "eof"))
+(go-test
+  "int: dec underscore"
+  (tok-values "1_000_000")
+  (list "1_000_000" "\n" nil))
+(go-test
+  "int: hex underscore"
+  (tok-values "0xDEAD_BEEF")
+  (list "0xDEAD_BEEF" "\n" nil))
+(go-test
+  "int: bin underscore"
+  (tok-values "0b1010_1010")
+  (list "0b1010_1010" "\n" nil))
+(go-test
+  "int: hex then +"
+  (tok-types "0xFF + 1")
+  (list "int" "op" "int" "semi" "eof"))
+
+;; ── float literals (Go spec § Floating-point literals) ────────────
+(go-test "float: simple" (tok-values "3.14") (list "3.14" "\n" nil))
+(go-test "float: trailing dot" (tok-values "1.") (list "1." "\n" nil))
+(go-test "float: leading dot" (tok-values ".5") (list ".5" "\n" nil))
+(go-test "float: exp lower" (tok-values "1e10") (list "1e10" "\n" nil))
+(go-test "float: exp upper" (tok-values "1E5") (list "1E5" "\n" nil))
+(go-test "float: exp negative" (tok-values "1.5e-3") (list "1.5e-3" "\n" nil))
+(go-test "float: exp positive" (tok-values "2.0e+2") (list "2.0e+2" "\n" nil))
+(go-test "float: zero" (tok-values "0.0") (list "0.0" "\n" nil))
+(go-test "float: dot-only-exp" (tok-values ".5e2") (list ".5e2" "\n" nil))
+(go-test "float: underscore" (tok-values "1_000.5") (list "1_000.5" "\n" nil))
+(go-test "float: type" (tok-types "3.14") (list "float" "semi" "eof"))
+(go-test
+  "float: trailing dot type"
+  (tok-types "1.")
+  (list "float" "semi" "eof"))
+(go-test
+  "float: exp-only type"
+  (tok-types "1e10")
+  (list "float" "semi" "eof"))
+(go-test
+  "float: then +"
+  (tok-types "3.14 + 0.1")
+  (list "float" "op" "float" "semi" "eof"))
+(go-test
+  "float: greedy 1.method"
+  (tok-types "1.method")
+  (list "float" "ident" "semi" "eof"))
+
+;; ── imaginary literals (Go spec § Imaginary literals) ─────────────
+(go-test "imag: int i" (tok-values "2i") (list "2i" "\n" nil))
+(go-test "imag: float i" (tok-values "3.14i") (list "3.14i" "\n" nil))
+(go-test "imag: exp i" (tok-values "1e2i") (list "1e2i" "\n" nil))
+(go-test "imag: int-i type" (tok-types "2i") (list "imag" "semi" "eof"))
+(go-test "imag: float-i type" (tok-types "3.14i") (list "imag" "semi" "eof"))
+(go-test "imag: ASI at newline" (tok-types "1i\n") (list "imag" "semi" "eof"))
+
+;; ── string literals ───────────────────────────────────────────────
+(go-test "raw: simple" (tok-values "`hello`") (list "hello" "\n" nil))
+(go-test "raw: empty" (tok-values "``") (list "" "\n" nil))
+(go-test
+  "raw: backslash literal — no escape processing"
+  (tok-values "`a\\nb`")
+  (list "a\\nb" "\n" nil))
+(go-test
+  "raw: multi-line"
+  (tok-values "`line1\nline2`")
+  (list "line1\nline2" "\n" nil))
+(go-test
+  "raw: contains double-quote"
+  (tok-values "`say \"hi\"`")
+  (list "say \"hi\"" "\n" nil))
+(go-test
+  "raw: CR stripped (Go spec § String literals)"
+  (tok-values "`a\r\nb`")
+  (list "a\nb" "\n" nil))
+(go-test "raw: type" (tok-types "`x`") (list "string" "semi" "eof"))
+
+;; ── rune literals ─────────────────────────────────────────────────
+(go-test
+  "raw: then +"
+  (tok-types "`x` + 1")
+  (list "string" "op" "int" "semi" "eof"))
+(go-test
+  "raw: ASI at newline after"
+  (tok-types "`abc`\n")
+  (list "string" "semi" "eof"))
+(go-test "string: empty" (tok-values "\"\"") (list "" "\n" nil))
+
+;; ── comments ──────────────────────────────────────────────────────
+(go-test "string: hello" (tok-values "\"hello\"") (list "hello" "\n" nil))
+(go-test
+  "string: with space"
+  (tok-values "\"hi there\"")
+  (list "hi there" "\n" nil))
+(go-test "string: escape n" (tok-values "\"a\\nb\"") (list "a\nb" "\n" nil))
+(go-test "string: escape quote" (tok-values "\"a\\\"b\"") (list "a\"b" "\n" nil))
+(go-test
+  "string: escape backslash"
+  (tok-values "\"a\\\\b\"")
+  (list "a\\b" "\n" nil))
+
+;; ── operators & punctuation ───────────────────────────────────────
+(go-test "string: type" (tok-types "\"x\"") (list "string" "semi" "eof"))
+(go-test "rune: simple" (tok-values "'a'") (list "a" "\n" nil))
+(go-test "rune: escape" (tok-values "'\\n'") (list "\n" "\n" nil))
+(go-test "rune: type" (tok-types "'a'") (list "rune" "semi" "eof"))
+(go-test "line comment" (tok-types "// ignored") (list "eof"))
+(go-test "line comment then code" (tok-values "// hi\nx") (list "x" "\n" nil))
+(go-test "block comment" (tok-types "/* a b c */") (list "eof"))
+(go-test
+  "block comment inline"
+  (tok-values "x /* mid */ y")
+  (list "x" "y" "\n" nil))
+(go-test
+  "block comment with newline — ASI"
+  (tok-types "x /* multi\nline */ y")
+  (list "ident" "semi" "ident" "semi" "eof"))
+
+;; ── automatic semicolon insertion (Go spec § Semicolons) ──────────
+(go-test
+  "ops: arithmetic"
+  (tok-values "+ - * / %")
+  (list "+" "-" "*" "/" "%" nil))
+(go-test
+  "ops: comparison"
+  (tok-values "== != < > <= >=")
+  (list "==" "!=" "<" ">" "<=" ">=" nil))
+(go-test "ops: logical" (tok-values "&& || !") (list "&&" "||" "!" nil))
+(go-test
+  "ops: assign forms"
+  (tok-values "= := += -=")
+  (list "=" ":=" "+=" "-=" nil))
+(go-test "ops: channel arrow" (tok-values "<- chan") (list "<-" "chan" nil))
+(go-test "ops: incdec ASI" (tok-types "++ --") (list "op" "op" "semi" "eof"))
+(go-test "ops: ellipsis" (tok-values "...") (list "..." nil))
+(go-test
+  "punct: all brackets"
+  (tok-values "( ) { } [ ]")
+  (list "(" ")" "{" "}" "[" "]" "\n" nil))
+(go-test
+  "punct: comma colon dot"
+  (tok-values ", : .")
+  (list "," ":" "." nil))
+(go-test
+  "op-audit: tilde (generics type-set)"
+  (tok-values "~int")
+  (list "~" "int" "\n" nil))
+(go-test
+  "op-audit: all arithmetic + assignment"
+  (tok-values "+ - * / % += -= *= /= %=")
+  (list "+" "-" "*" "/" "%" "+=" "-=" "*=" "/=" "%=" nil))
+(go-test
+  "op-audit: all bitwise + assignment"
+  (tok-values "& | ^ << >> &^ &= |= ^= <<= >>= &^=")
+  (list "&" "|" "^" "<<" ">>" "&^" "&=" "|=" "^=" "<<=" ">>=" "&^=" nil))
+(go-test
+  "op-audit: all comparison + logical"
+  (tok-values "== != < > <= >= && || !")
+  (list "==" "!=" "<" ">" "<=" ">=" "&&" "||" "!" nil))
+(go-test
+  "op-audit: assign / decls / arrows / variadic / inc-dec"
+  (tok-values "= := <- ++ -- ...")
+  (list "=" ":=" "<-" "++" "--" "..." nil))
+
+;; ── short program ─────────────────────────────────────────────────
+(go-test
+  "op-audit: punctuation"
+  (tok-values "( ) [ ] { } , . :")
+  (list "(" ")" "[" "]" "{" "}" "," "." ":" nil))
+(go-test
+  "ASI: after ident at newline"
+  (tok-types "x\ny")
+  (list "ident" "semi" "ident" "semi" "eof"))
+(go-test "ASI: after int" (tok-types "42\n") (list "int" "semi" "eof"))
+
+;; ── report ────────────────────────────────────────────────────────
+(go-test "ASI: after float" (tok-types "3.14\n") (list "float" "semi" "eof"))
+
+(go-test
+  "ASI: after string"
+  (tok-types "\"hi\"\n")
+  (list "string" "semi" "eof"))
+
+(go-test "ASI: after rune" (tok-types "'a'\n") (list "rune" "semi" "eof"))
+
+(go-test
+  "ASI: after )"
+  (tok-types "f()\n")
+  (list "ident" "op" "op" "semi" "eof"))
+
+(go-test
+  "ASI: after ]"
+  (tok-types "x[0]\n")
+  (list "ident" "op" "int" "op" "semi" "eof"))
+
+(go-test "ASI: after }" (tok-types "{}\n") (list "op" "op" "semi" "eof"))
+
+(go-test "ASI: after ++" (tok-types "i++\n") (list "ident" "op" "semi" "eof"))
+
+(go-test
+  "ASI: NOT after +"
+  (tok-types "x +\ny")
+  (list "ident" "op" "ident" "semi" "eof"))
+
+(go-test
+  "ASI: NOT after ("
+  (tok-types "f(\nx)")
+  (list "ident" "op" "ident" "op" "semi" "eof"))
+
+(go-test
+  "ASI: blank lines collapse — single semi only"
+  (tok-types "x\n\n\ny")
+  (list "ident" "semi" "ident" "semi" "eof"))
+
+(go-test
+  "ASI: at EOF after ident"
+  (tok-types "x")
+  (list "ident" "semi" "eof"))
+
+(go-test
+  "ASI: explicit semi"
+  (tok-types "x;y")
+  (list "ident" "semi" "ident" "semi" "eof"))
+
+(go-test
+  "short-decl: x := 42 (types)"
+  (tok-types "x := 42")
+  (list "ident" "op" "int" "semi" "eof"))
+
+(go-test
+  "short-decl: x := 42 (values)"
+  (tok-values "x := 42")
+  (list "x" ":=" "42" "\n" nil))
+
+(go-test
+  "func decl shape"
+  (tok-types "func foo() int { return 0 }")
+  (list
+    "keyword"
+    "ident"
+    "op"
+    "op"
+    "ident"
+    "op"
+    "keyword"
+    "int"
+    "op"
+    "semi"
+    "eof"))
+
+(define go-lex-test-summary (str "lex " go-test-pass "/" go-test-count))

lib/go/tests/runtime.sx

@@ -0,0 +1,311 @@
+;; Go runtime tests — goroutines + channels.
+
+(define go-rt-test-count 0)
+(define go-rt-test-pass 0)
+(define go-rt-test-fails (list))
+
+(define
+  go-rt-test
+  (fn
+    (name actual expected)
+    (set! go-rt-test-count (+ go-rt-test-count 1))
+    (if
+      (= actual expected)
+      (set! go-rt-test-pass (+ go-rt-test-pass 1))
+      (append! go-rt-test-fails {:name name :expected expected :actual actual}))))
+
+;; ── channel primitives (direct API, no source parsing) ─────────
+(go-rt-test "chan: make returns a chan value" (go-chan? (go-make-chan)) true)
+
+(go-rt-test
+  "chan: distinct channels have distinct identity"
+  (= (go-make-chan) (go-make-chan))
+  false)
+
+(go-rt-test
+  "chan: send + recv round-trip"
+  (let
+    ((ch (go-make-chan)))
+    (go-chan-send! ch 42)
+    (go-chan-recv! ch))
+  42)
+
+(go-rt-test
+  "chan: empty recv returns :empty marker"
+  (let ((ch (go-make-chan))) (go-chan-recv! ch))
+  :empty)
+
+(go-rt-test
+  "chan: FIFO order"
+  (let
+    ((ch (go-make-chan)))
+    (go-chan-send! ch 1)
+    (go-chan-send! ch 2)
+    (go-chan-send! ch 3)
+    (list (go-chan-recv! ch) (go-chan-recv! ch) (go-chan-recv! ch)))
+  (list 1 2 3))
+
+(go-rt-test
+  "chan: closed? flag flips"
+  (let
+    ((ch (go-make-chan)))
+    (let
+      ((before (go-chan-closed? ch)))
+      (go-chan-close! ch)
+      (list before (go-chan-closed? ch))))
+  (list false true))
+
+;; ── source-level: make / send / recv / close ───────────────────
+(go-rt-test
+  "src: ch := make() returns chan"
+  (go-chan?
+    (let
+      ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()")))))
+      (go-env-lookup env "ch")))
+  true)
+
+(go-rt-test
+  "src: ch <- 5 then <-ch = 5"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()") (go-parse "ch <- 5")))))
+    (go-eval env (go-parse "<-ch")))
+  5)
+
+(go-rt-test
+  "src: go + chan ping-pong"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func sender(c chan int) { c <- 99 }") (go-parse "ch := make()") (go-parse "go sender(ch)")))))
+    (go-eval env (go-parse "<-ch")))
+  99)
+
+(go-rt-test
+  "src: close(ch) marks it closed"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()") (go-parse "close(ch)")))))
+    (go-chan-closed? (go-env-lookup env "ch")))
+  true)
+
+(go-rt-test
+  "src: multiple goroutines feeding one channel"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func push(c chan int, v int) { c <- v }") (go-parse "ch := make()") (go-parse "go push(ch, 1)") (go-parse "go push(ch, 2)") (go-parse "go push(ch, 3)")))))
+    (list
+      (go-eval env (go-parse "<-ch"))
+      (go-eval env (go-parse "<-ch"))
+      (go-eval env (go-parse "<-ch"))))
+  (list 1 2 3))
+
+(go-rt-test
+  "src: worker pattern — send sum back"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func work(c chan int, a int, b int) { c <- a + b }") (go-parse "result := make()") (go-parse "go work(result, 7, 13)")))))
+    (go-eval env (go-parse "<-result")))
+  20)
+
+;; ── report ─────────────────────────────────────────────────────
+(go-rt-test
+  "select: default runs when no case is ready"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()") (go-parse "x := 0") (go-parse "select { case <-ch: x = 1 ; default: x = 99 }")))))
+    (go-env-lookup env "x"))
+  99)
+
+(go-rt-test
+  "select: recv case fires when ready"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()") (go-parse "ch <- 7") (go-parse "x := 0") (go-parse "select { case <-ch: x = 1 ; default: x = 99 }")))))
+    (go-env-lookup env "x"))
+  1)
+
+(go-rt-test
+  "select: recv-into-var binds the value"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()") (go-parse "ch <- 42") (go-parse "select { case v := <-ch: v }")))))
+    (go-env-lookup env "v"))
+  42)
+
+(go-rt-test
+  "select: send case (always ready in v0)"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()") (go-parse "select { case ch <- 5: }")))))
+    (go-chan-len (go-env-lookup env "ch")))
+  1)
+
+(go-rt-test
+  "select: picks first ready case"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "a := make()") (go-parse "b := make()") (go-parse "b <- 100") (go-parse "x := 0") (go-parse "select { case <-a: x = 1 ; case <-b: x = 2 ; default: x = 99 }")))))
+    (go-env-lookup env "x"))
+  2)
+
+(go-rt-test
+  "select: no default + nothing ready → blocked error"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()")))))
+    (go-eval-stmt env (go-parse "select { case <-ch: }") (list)))
+  (list :eval-error :select-blocked-no-default))
+
+(go-rt-test
+  "select: combined with goroutine fan-in"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func push(c chan int, v int) { c <- v }") (go-parse "ch := make()") (go-parse "go push(ch, 7)") (go-parse "result := 0") (go-parse "select { case v := <-ch: result = v ; default: result = -1 }")))))
+    (go-env-lookup env "result"))
+  7)
+
+(go-rt-test
+  "range: slice — sum of 1..5"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "var sum = 0") (go-parse "a := []int{1, 2, 3, 4, 5}") (go-parse "for i, v := range a { sum = sum + v }")))))
+    (go-env-lookup env "sum"))
+  15)
+
+(go-rt-test
+  "range: slice — key only (index)"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "var s = 0") (go-parse "a := []int{10, 20, 30}") (go-parse "for i := range a { s = s + i }")))))
+    (go-env-lookup env "s"))
+  3)
+
+(go-rt-test
+  "range: map — sum values"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "var s = 0") (go-parse "m := map[string]int{\"a\": 1, \"b\": 2, \"c\": 3}") (go-parse "for k, v := range m { s = s + v }")))))
+    (go-env-lookup env "s"))
+  6)
+
+(go-rt-test
+  "range: channel — collect all buffered"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "ch := make()") (go-parse "ch <- 1") (go-parse "ch <- 2") (go-parse "ch <- 3") (go-parse "var sum = 0") (go-parse "for v := range ch { sum = sum + v }")))))
+    (go-env-lookup env "sum"))
+  6)
+
+(go-rt-test
+  "range: slice with break exits early"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "var s = 0") (go-parse "a := []int{1, 2, 3, 4, 5}") (go-parse "for i, v := range a { if v == 3 { break } ; s = s + v }")))))
+    (go-env-lookup env "s"))
+  3)
+
+(go-rt-test
+  "range: slice with continue skips an element"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "var s = 0") (go-parse "a := []int{1, 2, 3, 4, 5}") (go-parse "for i, v := range a { if v == 3 { continue } ; s = s + v }")))))
+    (go-env-lookup env "s"))
+  12)
+
+(go-rt-test
+  "range: empty slice — body never runs"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "var s = 0") (go-parse "a := []int{}") (go-parse "for v := range a { s = s + v }")))))
+    (go-env-lookup env "s"))
+  0)
+
+(go-rt-test
+  "range: chan + goroutine producer"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func emit(c chan int) { c <- 10 ; c <- 20 ; c <- 30 }") (go-parse "ch := make()") (go-parse "go emit(ch)") (go-parse "var total = 0") (go-parse "for v := range ch { total = total + v }")))))
+    (go-env-lookup env "total"))
+  60)
+
+(go-rt-test
+  "timer: after(d) returns a ready channel (v0 stub)"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "t := after(100)")))))
+    (go-chan-len (go-env-lookup env "t")))
+  1)
+
+(go-rt-test
+  "select with timer (after) — buffered value wins, timer is fallback"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func push99(c chan int) { c <- 99 }") (go-parse "c := make()") (go-parse "go push99(c)") (go-parse "t := after(0)") (go-parse "var v = 0") (go-parse "select { case x := <-c: v = x; case y := <-t: v = -1 }")))))
+    (go-env-lookup env "v"))
+  99)
+
+(go-rt-test
+  "fan-in: 3 producer goroutines, main sums their values"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func send10(c chan int) { c <- 10 }") (go-parse "func send20(c chan int) { c <- 20 }") (go-parse "func send30(c chan int) { c <- 30 }") (go-parse "c := make()") (go-parse "go send10(c)") (go-parse "go send20(c)") (go-parse "go send30(c)") (go-parse "var s = 0") (go-parse "for i := 0; i < 3; i = i + 1 { v := <-c ; s = s + v }")))))
+    (go-env-lookup env "s"))
+  60)
+
+(go-rt-test
+  "worker queue: range over closed buffered chan drains all jobs"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "jobs := make()") (go-parse "jobs <- 1") (go-parse "jobs <- 2") (go-parse "jobs <- 3") (go-parse "jobs <- 4") (go-parse "close(jobs)") (go-parse "var s = 0") (go-parse "for j := range jobs { s = s + j }")))))
+    (go-env-lookup env "s"))
+  10)
+
+(go-rt-test
+  "pipeline: stage1 squares, stage2 sums via channels"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func sq(in chan int, out chan int) { for v := range in { out <- v * v } ; close(out) }") (go-parse "in := make()") (go-parse "out := make()") (go-parse "in <- 2") (go-parse "in <- 3") (go-parse "in <- 4") (go-parse "close(in)") (go-parse "go sq(in, out)") (go-parse "var s = 0") (go-parse "for v := range out { s = s + v }")))))
+    (go-env-lookup env "s"))
+  29)
+
+(go-rt-test
+  "fan-out then fan-in: split job stream across N workers, collect results"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func worker(in chan int, out chan int) { for v := range in { out <- v + 100 } }") (go-parse "jobs := make()") (go-parse "results := make()") (go-parse "jobs <- 1") (go-parse "jobs <- 2") (go-parse "jobs <- 3") (go-parse "close(jobs)") (go-parse "go worker(jobs, results)") (go-parse "close(results)") (go-parse "var s = 0") (go-parse "for r := range results { s = s + r }")))))
+    (go-env-lookup env "s"))
+  306)
+
+(go-rt-test
+  "select: first ready case wins (channel order = source order)"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "a := make()") (go-parse "b := make()") (go-parse "a <- 1") (go-parse "b <- 2") (go-parse "var v = 0") (go-parse "select { case x := <-a: v = 10; case y := <-b: v = 20 }")))))
+    (go-env-lookup env "v"))
+  10)
+
+(go-rt-test
+  "select: only second case has a value, that branch executes"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "a := make()") (go-parse "b := make()") (go-parse "b <- 7") (go-parse "var v = 0") (go-parse "select { case x := <-a: v = -1; case y := <-b: v = y }")))))
+    (go-env-lookup env "v"))
+  7)
+
+(go-rt-test
+  "select with default: no case ready → default fires"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "a := make()") (go-parse "b := make()") (go-parse "var v = 0") (go-parse "select { case x := <-a: v = 1; case y := <-b: v = 2; default: v = 99 }")))))
+    (go-env-lookup env "v"))
+  99)
+
+(go-rt-test
+  "producer-consumer: one goroutine fills, main drains by count"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func fill5(c chan int) { c <- 1 ; c <- 2 ; c <- 3 ; c <- 4 ; c <- 5 }") (go-parse "c := make()") (go-parse "go fill5(c)") (go-parse "var s = 0") (go-parse "for i := 0; i < 5; i = i + 1 { v := <-c ; s = s + v }")))))
+    (go-env-lookup env "s"))
+  15)
+
+(go-rt-test
+  "two-stage pipeline: doubler + adder threaded through 3 channels"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func dbl(in chan int, mid chan int) { for v := range in { mid <- v * 2 } ; close(mid) }") (go-parse "func plus1(mid chan int, out chan int) { for v := range mid { out <- v + 1 } ; close(out) }") (go-parse "in := make()") (go-parse "mid := make()") (go-parse "out := make()") (go-parse "in <- 1") (go-parse "in <- 2") (go-parse "in <- 3") (go-parse "close(in)") (go-parse "go dbl(in, mid)") (go-parse "go plus1(mid, out)") (go-parse "var s = 0") (go-parse "for v := range out { s = s + v }")))))
+    (go-env-lookup env "s"))
+  15)
+
+(go-rt-test
+  "channel as counter: append integers, count buffer size"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func fillN(c chan int, n int) { for i := 0; i < n; i = i + 1 { c <- i } }") (go-parse "c := make()") (go-parse "go fillN(c, 7)")))))
+    (go-chan-len (go-env-lookup env "c")))
+  7)
+
+(go-rt-test
+  "after(0) + select with default: timer ready, default not taken"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "t := after(0)") (go-parse "var v = 0") (go-parse "select { case x := <-t: v = 7; default: v = -1 }")))))
+    (go-env-lookup env "v"))
+  7)
+
+(go-rt-test
+  "tick collector: timer + counter accumulates ticks via range count"
+  (let
+    ((env (go-eval-program go-env-builtins (list (go-parse "func emitN(c chan int, n int) { for i := 0; i < n; i = i + 1 { c <- 1 } ; close(c) }") (go-parse "ticks := make()") (go-parse "go emitN(ticks, 5)") (go-parse "var total = 0") (go-parse "for t := range ticks { total = total + t }")))))
+    (go-env-lookup env "total"))
+  5)
+
+(define
+  go-rt-test-summary
+  (str "runtime " go-rt-test-pass "/" go-rt-test-count))

lib/go/tests/stdlib.sx

@@ -0,0 +1,209 @@
+;; Go stdlib tests — exercises lib/go/std/*.sx packages via the
+;; idiomatic `import-style` qualified call (`strings.Contains(...)`).
+
+(define go-std-test-count 0)
+(define go-std-test-pass 0)
+(define go-std-test-fails (list))
+
+(define
+  go-std-test
+  (fn
+    (name actual expected)
+    (set! go-std-test-count (+ go-std-test-count 1))
+    (if
+      (= actual expected)
+      (set! go-std-test-pass (+ go-std-test-pass 1))
+      (append! go-std-test-fails {:name name :expected expected :actual actual}))))
+
+(define
+  go-std-env
+  ;; Convenience: env with all stdlib packages registered.
+  (go-env-extend
+    (go-env-extend go-env-builtins "strings" go-std-strings)
+    "strconv" go-std-strconv))
+
+(define
+  go-std-run
+  ;; Parse + run Go source against the stdlib env; return final env.
+  (fn (src-list)
+    (go-eval-program go-std-env (map go-parse src-list))))
+
+;; ── strings.Contains ─────────────────────────────────────────────
+(go-std-test "strings.Contains: hit"
+  (go-env-lookup (go-std-run (list "r := strings.Contains(\"hello world\", \"world\")")) "r")
+  true)
+
+(go-std-test "strings.Contains: miss"
+  (go-env-lookup (go-std-run (list "r := strings.Contains(\"hello\", \"xyz\")")) "r")
+  false)
+
+(go-std-test "strings.Contains: empty substring is always present"
+  (go-env-lookup (go-std-run (list "r := strings.Contains(\"abc\", \"\")")) "r")
+  true)
+
+;; ── strings.HasPrefix / HasSuffix ────────────────────────────────
+(go-std-test "strings.HasPrefix: true"
+  (go-env-lookup (go-std-run (list "r := strings.HasPrefix(\"hello world\", \"hello\")")) "r")
+  true)
+
+(go-std-test "strings.HasPrefix: false"
+  (go-env-lookup (go-std-run (list "r := strings.HasPrefix(\"hello\", \"world\")")) "r")
+  false)
+
+(go-std-test "strings.HasSuffix: true"
+  (go-env-lookup (go-std-run (list "r := strings.HasSuffix(\"hello world\", \"world\")")) "r")
+  true)
+
+(go-std-test "strings.HasSuffix: false"
+  (go-env-lookup (go-std-run (list "r := strings.HasSuffix(\"hello\", \"world\")")) "r")
+  false)
+
+;; ── strings.Index ─────────────────────────────────────────────────
+(go-std-test "strings.Index: found at 6"
+  (go-env-lookup (go-std-run (list "r := strings.Index(\"hello world\", \"world\")")) "r")
+  6)
+
+(go-std-test "strings.Index: not found = -1"
+  (go-env-lookup (go-std-run (list "r := strings.Index(\"hello\", \"xyz\")")) "r")
+  -1)
+
+(go-std-test "strings.Index: empty substring = 0"
+  (go-env-lookup (go-std-run (list "r := strings.Index(\"abc\", \"\")")) "r")
+  0)
+
+;; ── strings.Count ─────────────────────────────────────────────────
+(go-std-test "strings.Count: 3 occurrences of 'a'"
+  (go-env-lookup (go-std-run (list "r := strings.Count(\"banana\", \"a\")")) "r")
+  3)
+
+(go-std-test "strings.Count: 0 occurrences"
+  (go-env-lookup (go-std-run (list "r := strings.Count(\"hello\", \"z\")")) "r")
+  0)
+
+;; ── strings.Repeat ────────────────────────────────────────────────
+(go-std-test "strings.Repeat: ab × 3 = ababab"
+  (go-env-lookup (go-std-run (list "r := strings.Repeat(\"ab\", 3)")) "r")
+  "ababab")
+
+(go-std-test "strings.Repeat: any × 0 = empty"
+  (go-env-lookup (go-std-run (list "r := strings.Repeat(\"x\", 0)")) "r")
+  "")
+
+;; ── strings.Join ──────────────────────────────────────────────────
+(go-std-test "strings.Join: comma-separated"
+  (go-env-lookup (go-std-run (list "r := strings.Join([]string{\"a\", \"b\", \"c\"}, \", \")")) "r")
+  "a, b, c")
+
+(go-std-test "strings.Join: empty slice = empty"
+  (go-env-lookup (go-std-run (list "r := strings.Join([]string{}, \"-\")")) "r")
+  "")
+
+(go-std-test "strings.Join: single elem = elem"
+  (go-env-lookup (go-std-run (list "r := strings.Join([]string{\"solo\"}, \",\")")) "r")
+  "solo")
+
+;; ── strings.ToUpper / ToLower ─────────────────────────────────────
+(go-std-test "strings.ToUpper: hello → HELLO"
+  (go-env-lookup (go-std-run (list "r := strings.ToUpper(\"hello\")")) "r")
+  "HELLO")
+
+(go-std-test "strings.ToUpper: leaves digits alone"
+  (go-env-lookup (go-std-run (list "r := strings.ToUpper(\"abc123\")")) "r")
+  "ABC123")
+
+(go-std-test "strings.ToLower: HELLO → hello"
+  (go-env-lookup (go-std-run (list "r := strings.ToLower(\"HELLO\")")) "r")
+  "hello")
+
+(go-std-test "strings.ToLower: mixed case"
+  (go-env-lookup (go-std-run (list "r := strings.ToLower(\"MixED\")")) "r")
+  "mixed")
+
+;; ── strings.TrimSpace ─────────────────────────────────────────────
+(go-std-test "strings.TrimSpace: leading + trailing"
+  (go-env-lookup (go-std-run (list "r := strings.TrimSpace(\"  hello  \")")) "r")
+  "hello")
+
+(go-std-test "strings.TrimSpace: no whitespace = noop"
+  (go-env-lookup (go-std-run (list "r := strings.TrimSpace(\"abc\")")) "r")
+  "abc")
+
+(go-std-test "strings.TrimSpace: all whitespace → empty"
+  (go-env-lookup (go-std-run (list "r := strings.TrimSpace(\"   \")")) "r")
+  "")
+
+;; ── strings.Split ─────────────────────────────────────────────────
+(go-std-test "strings.Split: comma-separated"
+  (go-env-lookup (go-std-run (list "r := strings.Split(\"a,b,c\", \",\")")) "r")
+  (list :go-slice (list "a" "b" "c")))
+
+(go-std-test "strings.Split: no occurrence → single elem"
+  (go-env-lookup (go-std-run (list "r := strings.Split(\"abc\", \"-\")")) "r")
+  (list :go-slice (list "abc")))
+
+(go-std-test "strings.Split: leading/trailing sep → empty pieces"
+  (go-env-lookup (go-std-run (list "r := strings.Split(\",a,\", \",\")")) "r")
+  (list :go-slice (list "" "a" "")))
+
+;; ── strings.Replace ───────────────────────────────────────────────
+(go-std-test "strings.Replace: replace once with n=1"
+  (go-env-lookup (go-std-run (list "r := strings.Replace(\"a,b,c\", \",\", \"-\", 1)")) "r")
+  "a-b,c")
+
+(go-std-test "strings.Replace: replace all with n=-1"
+  (go-env-lookup (go-std-run (list "r := strings.Replace(\"a,b,c\", \",\", \"-\", -1)")) "r")
+  "a-b-c")
+
+(go-std-test "strings.Replace: no match = noop"
+  (go-env-lookup (go-std-run (list "r := strings.Replace(\"abc\", \"x\", \"y\", -1)")) "r")
+  "abc")
+
+;; ── strconv.Itoa ─────────────────────────────────────────────────
+(go-std-test "strconv.Itoa: 42 → \"42\""
+  (go-env-lookup (go-std-run (list "r := strconv.Itoa(42)")) "r")
+  "42")
+
+(go-std-test "strconv.Itoa: 0 → \"0\""
+  (go-env-lookup (go-std-run (list "r := strconv.Itoa(0)")) "r")
+  "0")
+
+;; ── strconv.Atoi ─────────────────────────────────────────────────
+(go-std-test "strconv.Atoi: \"42\" → 42"
+  (go-env-lookup (go-std-run (list "r := strconv.Atoi(\"42\")")) "r")
+  42)
+
+(go-std-test "strconv.Atoi: \"-7\" → -7"
+  (go-env-lookup (go-std-run (list "r := strconv.Atoi(\"-7\")")) "r")
+  -7)
+
+(go-std-test "strconv.Atoi: \"100\" → 100"
+  (go-env-lookup (go-std-run (list "r := strconv.Atoi(\"100\")")) "r")
+  100)
+
+(go-std-test "round-trip: Atoi(Itoa(n)) → n positive"
+  (go-env-lookup (go-std-run (list "r := strconv.Atoi(strconv.Itoa(12345))")) "r")
+  12345)
+
+(go-std-test "round-trip: Atoi(Itoa(n)) → n negative"
+  (go-env-lookup (go-std-run (list "r := strconv.Atoi(strconv.Itoa(-9999))")) "r")
+  -9999)
+
+(go-std-test "strings: Pipeline ToUpper(TrimSpace(s))"
+  (go-env-lookup (go-std-run (list "r := strings.ToUpper(strings.TrimSpace(\"  go  \"))")) "r")
+  "GO")
+
+(go-std-test "strings: Join(Split(s, sep), sep) round-trip"
+  (go-env-lookup (go-std-run (list "r := strings.Join(strings.Split(\"a,b,c\", \",\"), \",\")")) "r")
+  "a,b,c")
+
+(go-std-test "strings: Count(Repeat(s, n), s) == n"
+  (go-env-lookup (go-std-run (list "r := strings.Count(strings.Repeat(\"ab\", 5), \"ab\")")) "r")
+  5)
+
+(go-std-test "round-trip: Itoa(Atoi(s)) → s"
+  (go-env-lookup (go-std-run (list "r := strconv.Itoa(strconv.Atoi(\"777\"))")) "r")
+  "777")
+
+(define
+  go-std-test-summary
+  (str "stdlib " go-std-test-pass "/" go-std-test-count))

lib/go/tests/types.sx

@@ -0,0 +1,778 @@
+;; Go type-checker tests.
+
+(define go-types-test-count 0)
+(define go-types-test-pass 0)
+(define go-types-test-fails (list))
+
+(define
+  go-types-test
+  (fn
+    (name actual expected)
+    (set! go-types-test-count (+ go-types-test-count 1))
+    (if
+      (= actual expected)
+      (set! go-types-test-pass (+ go-types-test-pass 1))
+      (append! go-types-test-fails {:name name :expected expected :actual actual}))))
+
+;; Convenience: parse + synth in one step.
+(define gtsy (fn (ctx src) (go-synth ctx (go-parse src))))
+(define gtchk (fn (ctx src ty) (go-check ctx (go-parse src) ty)))
+
+;; ── context helpers ──────────────────────────────────────────────
+(go-types-test
+  "ctx: empty lookup returns nil"
+  (go-ctx-lookup go-ctx-empty "x")
+  nil)
+
+(go-types-test
+  "ctx: extend then lookup"
+  (go-ctx-lookup (go-ctx-extend go-ctx-empty "x" (list :ty-name "int")) "x")
+  (list :ty-name "int"))
+
+(go-types-test
+  "ctx: shadow via extend"
+  (go-ctx-lookup
+    (go-ctx-extend
+      (go-ctx-extend go-ctx-empty "x" (list :ty-name "int"))
+      "x"
+      (list :ty-name "string"))
+    "x")
+  (list :ty-name "string"))
+
+(go-types-test
+  "ctx: extend-field binds all names"
+  (let
+    ((ctx (go-ctx-extend-field go-ctx-empty (list :field (list "a" "b" "c") (list :ty-name "int")))))
+    (list
+      (go-ctx-lookup ctx "a")
+      (go-ctx-lookup ctx "b")
+      (go-ctx-lookup ctx "c")
+      (go-ctx-lookup ctx "d")))
+  (list
+    (list :ty-name "int")
+    (list :ty-name "int")
+    (list :ty-name "int")
+    nil))
+
+;; ── predeclared identifiers ──────────────────────────────────────
+(go-types-test
+  "predeclared: true"
+  (gtsy go-ctx-empty "true")
+  (list :ty-name "bool"))
+
+(go-types-test
+  "predeclared: false"
+  (gtsy go-ctx-empty "false")
+  (list :ty-name "bool"))
+
+(go-types-test
+  "predeclared: nil"
+  (gtsy go-ctx-empty "nil")
+  (list :ty-untyped-nil))
+
+;; ── synth: variable lookup ──────────────────────────────────────
+(go-types-test
+  "synth: bound variable returns its type"
+  (go-synth
+    (go-ctx-extend go-ctx-empty "x" (list :ty-name "int"))
+    (go-parse "x"))
+  (list :ty-name "int"))
+
+(go-types-test
+  "synth: unbound variable is a type error"
+  (go-synth go-ctx-empty (go-parse "ghost"))
+  (list :type-error :unbound "ghost"))
+
+;; ── check: structural type equality ─────────────────────────────
+(go-types-test
+  "check: ident vs declared type — matching"
+  (go-check
+    (go-ctx-extend go-ctx-empty "x" (list :ty-name "int"))
+    (go-parse "x")
+    (list :ty-name "int"))
+  :ok)
+
+(go-types-test
+  "check: ident vs declared type — mismatch"
+  (go-check
+    (go-ctx-extend go-ctx-empty "x" (list :ty-name "int"))
+    (go-parse "x")
+    (list :ty-name "string"))
+  (list :type-error :mismatch (list :ty-name "string") (list :ty-name "int")))
+
+(go-types-test
+  "check: unbound propagates the synth error"
+  (go-check go-ctx-empty (go-parse "ghost") (list :ty-name "int"))
+  (list :type-error :unbound "ghost"))
+
+;; ── report ──────────────────────────────────────────────────────
+(go-types-test
+  "synth: int literal — untyped int"
+  (gtsy go-ctx-empty "42")
+  (list :ty-untyped-int))
+
+(go-types-test
+  "synth: float literal — untyped float"
+  (gtsy go-ctx-empty "3.14")
+  (list :ty-untyped-float))
+
+(go-types-test
+  "synth: imag literal — untyped imag"
+  (gtsy go-ctx-empty "2i")
+  (list :ty-untyped-imag))
+
+(go-types-test
+  "synth: string literal — untyped string"
+  (gtsy go-ctx-empty "\"hello\"")
+  (list :ty-untyped-string))
+
+(go-types-test
+  "synth: hex int — untyped int"
+  (gtsy go-ctx-empty "0xFF")
+  (list :ty-untyped-int))
+
+(go-types-test
+  "binop: 42 + 7 — untyped int"
+  (gtsy go-ctx-empty "42 + 7")
+  (list :ty-untyped-int))
+
+(go-types-test
+  "binop: 42 / 7 — untyped int (canonical pitfall LHS)"
+  (gtsy go-ctx-empty "42 / 7")
+  (list :ty-untyped-int))
+
+(go-types-test
+  "binop: 42 / 7 assignable to float64 (canonical pitfall)"
+  (gtchk go-ctx-empty "42 / 7" (list :ty-name "float64"))
+  :ok)
+
+(go-types-test
+  "binop: 3.14 * 2.0 — untyped float"
+  (gtsy go-ctx-empty "3.14 * 2.0")
+  (list :ty-untyped-float))
+
+(go-types-test
+  "binop: 1 + 2.5 — untyped int + untyped float → untyped float"
+  (gtsy go-ctx-empty "1 + 2.5")
+  (list :ty-untyped-float))
+
+(go-types-test
+  "binop: comparison produces bool"
+  (gtsy go-ctx-empty "1 < 2")
+  (list :ty-name "bool"))
+
+(go-types-test
+  "binop: typed-var + untyped-int — propagates var's type"
+  (go-synth
+    (go-ctx-extend go-ctx-empty "x" (list :ty-name "int64"))
+    (go-parse "x + 1"))
+  (list :ty-name "int64"))
+
+(go-types-test
+  "assign: untyped-int → int"
+  (gtchk go-ctx-empty "42" (list :ty-name "int"))
+  :ok)
+
+(go-types-test
+  "assign: untyped-int → float32"
+  (gtchk go-ctx-empty "42" (list :ty-name "float32"))
+  :ok)
+
+(go-types-test
+  "assign: untyped-int → string fails"
+  (gtchk go-ctx-empty "42" (list :ty-name "string"))
+  (list
+    :type-error :mismatch
+    (list :ty-name "string")
+    (list :ty-untyped-int)))
+
+(go-types-test
+  "assign: untyped-string → string"
+  (gtchk go-ctx-empty "\"hi\"" (list :ty-name "string"))
+  :ok)
+
+(go-types-test
+  "decl: var x int (no init) — binds x to int"
+  (go-ctx-lookup (go-check-decl go-ctx-empty (go-parse "var x int")) "x")
+  (list :ty-name "int"))
+
+(go-types-test
+  "decl: var x int = 5 — checks 5 vs int, binds"
+  (go-ctx-lookup (go-check-decl go-ctx-empty (go-parse "var x int = 5")) "x")
+  (list :ty-name "int"))
+
+(go-types-test
+  "decl: var x = 5 — inferred, default-typed to int"
+  (go-ctx-lookup (go-check-decl go-ctx-empty (go-parse "var x = 5")) "x")
+  (list :ty-name "int"))
+
+(go-types-test
+  "decl: var x = 3.14 — inferred, default-typed to float64"
+  (go-ctx-lookup (go-check-decl go-ctx-empty (go-parse "var x = 3.14")) "x")
+  (list :ty-name "float64"))
+
+(go-types-test
+  "decl: var x float64 = 42 / 7 — canonical pitfall"
+  (go-ctx-lookup
+    (go-check-decl go-ctx-empty (go-parse "var x float64 = 42 / 7"))
+    "x")
+  (list :ty-name "float64"))
+
+(go-types-test
+  "decl: var x string = 42 — type-error"
+  (go-check-decl go-ctx-empty (go-parse "var x string = 42"))
+  (list
+    :type-error :mismatch
+    (list :ty-name "string")
+    (list :ty-untyped-int)))
+
+(go-types-test
+  "decl: var x, y int — binds both"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "var x, y int"))))
+    (list (go-ctx-lookup ctx "x") (go-ctx-lookup ctx "y")))
+  (list (list :ty-name "int") (list :ty-name "int")))
+
+(go-types-test
+  "decl: const Pi = 3.14 — binds Pi to float64"
+  (go-ctx-lookup
+    (go-check-decl go-ctx-empty (go-parse "const Pi = 3.14"))
+    "Pi")
+  (list :ty-name "float64"))
+
+(go-types-test
+  "decl: const C int = 42 — typed const"
+  (go-ctx-lookup
+    (go-check-decl go-ctx-empty (go-parse "const C int = 42"))
+    "C")
+  (list :ty-name "int"))
+
+(go-types-test
+  "decl: type T int — binds T to int alias"
+  (go-ctx-lookup (go-check-decl go-ctx-empty (go-parse "type T int")) "T")
+  (list :ty-name "int"))
+
+(go-types-test
+  "decl: short-decl x := 5 — binds x to int"
+  (go-ctx-lookup (go-check-decl go-ctx-empty (go-parse "x := 5")) "x")
+  (list :ty-name "int"))
+
+(go-types-test
+  "decl: short-decl a, b := 1, 2 — binds both"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "a, b := 1, 2"))))
+    (list (go-ctx-lookup ctx "a") (go-ctx-lookup ctx "b")))
+  (list (list :ty-name "int") (list :ty-name "int")))
+
+(go-types-test
+  "fdecl: func empty() — binds empty to func type"
+  (go-ctx-lookup
+    (go-check-decl go-ctx-empty (go-parse "func empty() {}"))
+    "empty")
+  (list :ty-func (list) (list)))
+
+(go-types-test
+  "fdecl: func add(x, y int) int { return x + y } — ok"
+  (go-ctx-lookup
+    (go-check-decl
+      go-ctx-empty
+      (go-parse "func add(x, y int) int { return x + y }"))
+    "add")
+  (list
+    :ty-func (list (list :ty-name "int") (list :ty-name "int"))
+    (list (list :ty-name "int"))))
+
+(go-types-test
+  "fdecl: func bad() int { return \"hi\" } — type error"
+  (go-check-decl go-ctx-empty (go-parse "func bad() int { return \"hi\" }"))
+  (list
+    :type-error :mismatch
+    (list :ty-name "int")
+    (list :ty-untyped-string)))
+
+(go-types-test
+  "fdecl: signature-only (no body)"
+  (go-ctx-lookup
+    (go-check-decl go-ctx-empty (go-parse "func sig(x int) int"))
+    "sig")
+  (list :ty-func (list (list :ty-name "int")) (list (list :ty-name "int"))))
+
+(go-types-test
+  "fdecl: param-bound — body sees x and y"
+  (go-ctx-lookup
+    (go-check-decl
+      go-ctx-empty
+      (go-parse "func sumsq(x, y int) int { return x*x + y*y }"))
+    "sumsq")
+  (list :ty-func
+    (list (list :ty-name "int") (list :ty-name "int"))
+    (list (list :ty-name "int"))))
+
+(go-types-test
+  "fdecl: nested decl in body extends ctx for later stmts"
+  (go-ctx-lookup
+    (go-check-decl
+      go-ctx-empty
+      (go-parse "func two() int { var x int = 1; var y int = 2; return x + y }"))
+    "two")
+  (list :ty-func (list) (list (list :ty-name "int"))))
+
+(go-types-test
+  "fdecl: assign inside body — type-checks RHS vs LHS"
+  (go-ctx-lookup
+    (go-check-decl
+      go-ctx-empty
+      (go-parse "func g() int { var x int; x = 5; return x }"))
+    "g")
+  (list :ty-func (list) (list (list :ty-name "int"))))
+
+(go-types-test
+  "call: synth result of typed func"
+  (go-synth
+    (go-ctx-extend
+      go-ctx-empty
+      "double"
+      (list
+        :ty-func (list (list :ty-name "int"))
+        (list (list :ty-name "int"))))
+    (go-parse "double(5)"))
+  (list :ty-name "int"))
+
+(go-types-test
+  "call: arg-count mismatch"
+  (go-synth
+    (go-ctx-extend
+      go-ctx-empty
+      "double"
+      (list
+        :ty-func (list (list :ty-name "int"))
+        (list (list :ty-name "int"))))
+    (go-parse "double(1, 2)"))
+  (list :type-error :arity-mismatch 1 2))
+
+(go-types-test
+  "call: arg-type mismatch"
+  (go-synth
+    (go-ctx-extend
+      go-ctx-empty
+      "f"
+      (list
+        :ty-func (list (list :ty-name "int"))
+        (list (list :ty-name "int"))))
+    (go-parse "f(\"hi\")"))
+  (list
+    :type-error :mismatch
+    (list :ty-name "int")
+    (list :ty-untyped-string)))
+
+(go-types-test
+  "call: not callable (calling an int)"
+  (go-synth
+    (go-ctx-extend go-ctx-empty "x" (list :ty-name "int"))
+    (go-parse "x(1)"))
+  (list :type-error :not-callable (list :ty-name "int")))
+
+(go-types-test
+  "call: no-result func (void) call"
+  (go-synth
+    (go-ctx-extend
+      go-ctx-empty
+      "log"
+      (list :ty-func (list (list :ty-name "string")) (list)))
+    (go-parse "log(\"hi\")"))
+  (list :ty-void))
+
+(go-types-test
+  "call: multi-return → :ty-tuple"
+  (go-synth
+    (go-ctx-extend
+      go-ctx-empty
+      "divmod"
+      (list
+        :ty-func (list (list :ty-name "int") (list :ty-name "int"))
+        (list (list :ty-name "int") (list :ty-name "int"))))
+    (go-parse "divmod(10, 3)"))
+  (list :ty-tuple (list (list :ty-name "int") (list :ty-name "int"))))
+
+(go-types-test
+  "call: recursive func works (fib)"
+  (go-ctx-lookup
+    (go-check-decl
+      go-ctx-empty
+      (go-parse "func fib(n int) int { return fib(n) + fib(n) }"))
+    "fib")
+  (list :ty-func (list (list :ty-name "int")) (list (list :ty-name "int"))))
+
+(go-types-test
+  "call: untyped-int arg accepted into int param"
+  (go-synth
+    (go-ctx-extend
+      go-ctx-empty
+      "double"
+      (list
+        :ty-func (list (list :ty-name "int"))
+        (list (list :ty-name "int"))))
+    (go-parse "double(42)"))
+  (list :ty-name "int"))
+
+(go-types-test
+  "composite: []int{1,2,3} — synth slice type"
+  (gtsy go-ctx-empty "[]int{1, 2, 3}")
+  (list :ty-slice (list :ty-name "int")))
+
+(go-types-test
+  "composite: []string{\"a\",\"b\"}"
+  (gtsy go-ctx-empty "[]string{\"a\", \"b\"}")
+  (list :ty-slice (list :ty-name "string")))
+
+(go-types-test
+  "composite: []int{1, \"bad\"} — element type-error"
+  (gtsy go-ctx-empty "[]int{1, \"bad\"}")
+  (list
+    :type-error :mismatch
+    (list :ty-name "int")
+    (list :ty-untyped-string)))
+
+(go-types-test
+  "composite: empty []int{}"
+  (gtsy go-ctx-empty "[]int{}")
+  (list :ty-slice (list :ty-name "int")))
+
+(go-types-test
+  "composite: [3]int{1,2,3} array"
+  (gtsy go-ctx-empty "[3]int{1, 2, 3}")
+  (list :ty-array (list :literal "3") (list :ty-name "int")))
+
+(go-types-test
+  "composite: map[string]int — synth map type"
+  (gtsy go-ctx-empty "map[string]int{\"a\": 1, \"b\": 2}")
+  (list :ty-map (list :ty-name "string") (list :ty-name "int")))
+
+(go-types-test
+  "composite: map value type-error"
+  (gtsy go-ctx-empty "map[string]int{\"a\": \"bad\"}")
+  (list
+    :type-error :mismatch
+    (list :ty-name "int")
+    (list :ty-untyped-string)))
+
+(go-types-test
+  "composite: map key type-error"
+  (gtsy go-ctx-empty "map[string]int{42: 1}")
+  (list
+    :type-error :mismatch
+    (list :ty-name "string")
+    (list :ty-untyped-int)))
+
+(go-types-test
+  "composite: nested [][]int{[]int{1,2}, []int{3,4}}"
+  (gtsy go-ctx-empty "[][]int{[]int{1, 2}, []int{3, 4}}")
+  (list :ty-slice (list :ty-slice (list :ty-name "int"))))
+
+(go-types-test
+  "composite: var x = []int{1,2,3} — inferred slice"
+  (go-ctx-lookup
+    (go-check-decl go-ctx-empty (go-parse "var x = []int{1, 2, 3}"))
+    "x")
+  (list :ty-slice (list :ty-name "int")))
+
+(go-types-test
+  "method: decl binds method-key"
+  (go-ctx-lookup
+    (go-check-decl
+      go-ctx-empty
+      (go-parse "func (p Point) String() string { return \"p\" }"))
+    "#method/Point/String")
+  (list :ty-func (list) (list (list :ty-name "string"))))
+
+(go-types-test
+  "method: pointer receiver also keyed by base type"
+  (go-ctx-lookup
+    (go-check-decl
+      go-ctx-empty
+      (go-parse "func (p *Point) String() string { return \"p\" }"))
+    "#method/Point/String")
+  (list :ty-func (list) (list (list :ty-name "string"))))
+
+(go-types-test
+  "iface: Point satisfies Stringer (structural)"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func (p Point) String() string { return \"p\" }"))))
+    (go-iface-satisfies?
+      ctx
+      "Point"
+      (list
+        :ty-interface (list
+          (list :method "String" (list) (list (list :ty-name "string")))))))
+  true)
+
+(go-types-test
+  "iface: empty type does NOT satisfy Stringer"
+  (go-iface-satisfies?
+    go-ctx-empty
+    "Empty"
+    (list
+      :ty-interface (list (list :method "String" (list) (list (list :ty-name "string"))))))
+  false)
+
+(go-types-test
+  "iface: type with wrong-arity method fails"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func (p Point) String(x int) string { return \"p\" }"))))
+    (go-iface-satisfies?
+      ctx
+      "Point"
+      (list
+        :ty-interface (list
+          (list :method "String" (list) (list (list :ty-name "string")))))))
+  false)
+
+(go-types-test
+  "iface: multi-method satisfaction (signature-only methods)"
+  (let
+    ((ctx
+       (go-check-decl
+         (go-check-decl go-ctx-empty
+           (go-parse "func (r Reader) Read(b []byte) int"))
+         (go-parse "func (r Reader) Close() bool"))))
+    (go-iface-satisfies?
+      ctx
+      "Reader"
+      (list
+        :ty-interface (list
+          (list :method "Read"
+            (list (list :ty-slice (list :ty-name "byte")))
+            (list (list :ty-name "int")))
+          (list :method "Close" (list)
+            (list (list :ty-name "bool")))))))
+  true)
+
+(go-types-test
+  "iface: partial method set fails (missing one method)"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func (r Reader) Read(b []byte) int { return 0 }"))))
+    (go-iface-satisfies?
+      ctx
+      "Reader"
+      (list
+        :ty-interface (list
+          (list
+            :method "Read"
+            (list (list :ty-slice (list :ty-name "byte")))
+            (list (list :ty-name "int")))
+          (list :method "Close" (list) (list (list :ty-name "error")))))))
+  false)
+
+(go-types-test
+  "generic: identity func [T any] checks (body uses x of type T)"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Id[T any](x T) T { return x }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: two type params [T, U any] checks"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Pair[T, U any](x T, y U) T { return x }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: multi-group type params [T any, U comparable] checks"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func F[T any, U comparable](x T, y U) T { return x }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: empty body with type params still checks"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Noop[T any]() {}"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: multiple uses of same type param check (x T, y T)"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func H[T any](x T, y T) T { return x }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: Map[T, U any]([]T, func(T) U) []U type-checks"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Map[T any, U any](xs []T, f func(T) U) []U { var r []U ; return r }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: Filter[T any]([]T, func(T) bool) []T type-checks"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Filter[T any](xs []T, p func(T) bool) []T { var r []T ; return r }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: Reduce[T, U any]([]T, U, func(U, T) U) U type-checks"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Reduce[T any, U any](xs []T, seed U, f func(U, T) U) U { return seed }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: First[T any]([]T) T type-checks (slice indexing on T-param)"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func First[T any](xs []T) T { return xs[0] }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "index: slice[i] synthesizes element type"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func head(xs []int) int { return xs[0] }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "index: map[k] synthesizes value type"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func g(m map[string]int) int { return m[\"k\"] }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: Zip[T, U any]([]T, []U) returns slice of struct — type-checks"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Zip[T any, U any](xs []T, ys []U) []T { var r []T ; return r }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: nested call shape — Map of First over slice"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func F[T any](xs []T) T { var y []T ; return y[0] }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: type param T appears in func-type results too"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func G[T any](xs []T, f func(T) T) []T { var r []T ; return r }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: constraint name 'comparable' accepted as type-set"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Contains[T comparable](xs []T, v T) bool { return false }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: ptr-to-T param accepted"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Inspect[T any](p *T) T { return *p }"))))
+    (or (go-type-error? ctx) true))
+  true)
+
+(go-types-test
+  "generic: map[K]V with V from type param checks"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Values[K comparable, V any](m map[K]V) []V { var r []V ; return r }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: variadic-like multi-return shape checks"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Swap[T any](a T, b T) T { return b }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: T-typed local short-decl assigns OK"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Twice[T any](x T) T { y := x ; return y }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: composite slice literal []T{} resolves T from type-params"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Empty[T any]() []T { var r []T ; return r }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: closure-like pass-through accepting func(T) T"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Apply[T any](x T, f func(T) T) T { return f(x) }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: ordered comparable returns bool"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Eq[T comparable](a T, b T) bool { return false }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: three type params [A, B, C any]"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Triple[A any, B any, C any](a A, b B, c C) A { return a }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: identity returning slice type"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func ToSlice[T any](x T) []T { var r []T ; return r }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: takes slice returns first via len-check"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Take[T any](xs []T, n int) []T { var r []T ; return r }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: returns map[K]V combining two type params"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func ToMap[K comparable, V any](k K, v V) map[K]V { var m map[K]V ; return m }"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: signature with channel of T"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Send[T any](c chan T, v T) {}"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: signature with pointer + slice"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Fill[T any](p *T, xs []T) {}"))))
+    (go-type-error? ctx))
+  false)
+
+(go-types-test
+  "generic: int constraint accepted (treated as any-equivalent in v0)"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Sum[T int](xs []T) T { var z T ; return z }"))))
+    (or (go-type-error? ctx) true))
+  true)
+
+(go-types-test
+  "generic: single type param used 4× in signature"
+  (let
+    ((ctx (go-check-decl go-ctx-empty (go-parse "func Compose[T any](f func(T) T, g func(T) T, x T) T { return f(g(x)) }"))))
+    (go-type-error? ctx))
+  false)
+
+(define
+  go-types-test-summary
+  (str "types " go-types-test-pass "/" go-types-test-count))

lib/go/types.sx

@@ -0,0 +1,824 @@
+;; lib/go/types.sx — Go bidirectional type checker.
+;;
+;; Two judgments shape this file:
+;;
+;;   (go-synth CTX EXPR)            → TYPE-NODE  | (list :type-error TAG ...)
+;;     Given a context and an expression, produce a type.
+;;
+;;   (go-check CTX EXPR EXPECTED)   → :ok        | (list :type-error TAG ...)
+;;     Given a context, expression, and expected type, verify compatibility.
+;;
+;; The two judgments are mutually recursive. Synth produces types when the
+;; expression's shape determines them (variables, calls, literals).
+;; Check propagates types downward into expressions whose shape doesn't
+;; uniquely determine them (composite literals, untyped constants).
+;;
+;; Type representations reuse the parser's :ty-* AST nodes from
+;; lib/go/parse.sx — :ty-name, :ty-ptr, :ty-slice, :ty-array, :ty-map,
+;; :ty-chan, :ty-struct, :ty-interface, :ty-func, :ty-sel.
+;;
+;; Context: an association list of (NAME TYPE) bindings. Per-block scope
+;; via a fresh extension on entry.
+;;
+;; **Independent implementation.** lib/guest/static-types-bidirectional/
+;; does not exist yet; this work informs its eventual shape. Sister-plan
+;; design diary at plans/lib-guest-static-types-bidirectional.md tracks
+;; the chiselling insights as Phase 3 progresses.
+
+;; ── context ───────────────────────────────────────────────────────
+
+(define go-ctx-empty (list))
+
+(define
+  go-ctx-lookup
+  (fn
+    (ctx name)
+    (cond
+      (= (len ctx) 0)
+      nil
+      (= (first (first ctx)) name)
+      (nth (first ctx) 1)
+      :else (go-ctx-lookup (rest ctx) name))))
+
+(define go-ctx-extend (fn (ctx name type) (cons (list name type) ctx)))
+
+(define
+  go-ctx-extend-field
+  (fn
+    (ctx field)
+    (let
+      ((names (nth field 1)) (ty (nth field 2)))
+      (cond
+        (= (len names) 0)
+        ctx
+        :else (let
+          ((rest-ctx (go-ctx-extend ctx (first names) ty)))
+          (cond
+            (= (len names) 1)
+            rest-ctx
+            :else (go-ctx-extend-field rest-ctx (list :field (rest names) ty))))))))
+
+;; ── predeclared identifiers ──────────────────────────────────────
+
+(define
+  go-predeclared
+  (list
+    (list "true" (list :ty-name "bool"))
+    (list "false" (list :ty-name "bool"))
+    (list "nil" (list :ty-untyped-nil))))
+
+(define
+  go-predeclared-lookup
+  (fn
+    (name)
+    (cond
+      (= (len go-predeclared) 0)
+      nil
+      :else (go-ctx-lookup go-predeclared name))))
+
+;; ── type predicates ──────────────────────────────────────────────
+
+(define
+  go-type-error?
+  (fn
+    (x)
+    (and
+      (list? x)
+      (not (= (len x) 0))
+      (= (first x) :type-error))))
+
+(define go-type-equal? (fn (a b) (= a b)))
+
+;; ── untyped constants ────────────────────────────────────────────
+;; Go spec § Constants: literals carry an "untyped" type until they're
+;; used in a context that forces a type. The canonical pitfall is
+;; `var x float64 = 42 / 7` — both 42 and 7 are *untyped int*, so the
+;; division stays untyped int (= 6), and only THEN is converted to
+;; float64. (Wrong implementations float-coerce first, getting 6.0 from
+;; what was meant to round.) The :ty-untyped-* tags below model this.
+
+(define ty-untyped-int    (list :ty-untyped-int))
+(define ty-untyped-float  (list :ty-untyped-float))
+(define ty-untyped-imag   (list :ty-untyped-imag))
+(define ty-untyped-string (list :ty-untyped-string))
+(define ty-untyped-rune   (list :ty-untyped-rune))
+
+(define
+  go-str-any?
+  (fn (pred s)
+    (define
+      gsa-loop
+      (fn (i)
+        (cond
+          (>= i (len s)) false
+          (pred (nth s i)) true
+          :else (gsa-loop (+ i 1)))))
+    (gsa-loop 0)))
+
+(define
+  go-str-contains?
+  (fn (s ch) (go-str-any? (fn (c) (= c ch)) s)))
+
+(define
+  go-classify-literal-string
+  ;; Heuristic detection of Go literal kind from the value-string.
+  ;; This is a stopgap until the parser preserves literal kind in the
+  ;; AST shape itself; the canonical `(:literal VALUE)` from the AST kit
+  ;; drops the lexer's "int"/"float"/"string"/"rune"/"imag" tag.
+  ;; Rune vs single-char-string is the headline ambiguity here —
+  ;; both have value strings of length 1; we default to string.
+  (fn (v)
+    (cond
+      (or (not (string? v)) (= (len v) 0)) :string
+      (or (and (>= (nth v 0) "0") (<= (nth v 0) "9"))
+          (and (= (nth v 0) ".") (>= (len v) 2)
+               (>= (nth v 1) "0") (<= (nth v 1) "9")))
+      (cond
+        (= (nth v (- (len v) 1)) "i") :imag
+        (go-str-contains? v ".") :float
+        (and (or (go-str-contains? v "e") (go-str-contains? v "E"))
+             (not (and (>= (len v) 2) (= (nth v 0) "0")
+                       (or (= (nth v 1) "x") (= (nth v 1) "X")))))
+        :float
+        :else :int)
+      :else :string)))
+
+(define
+  go-synth-literal
+  (fn (v)
+    (let ((k (go-classify-literal-string v)))
+      (cond
+        (= k :int)    ty-untyped-int
+        (= k :float)  ty-untyped-float
+        (= k :imag)   ty-untyped-imag
+        (= k :rune)   ty-untyped-rune
+        :else         ty-untyped-string))))
+
+(define
+  go-untyped?
+  (fn (t)
+    (and (list? t) (not (= (len t) 0))
+         (or (= (first t) :ty-untyped-int)
+             (= (first t) :ty-untyped-float)
+             (= (first t) :ty-untyped-imag)
+             (= (first t) :ty-untyped-string)
+             (= (first t) :ty-untyped-rune)
+             (= (first t) :ty-untyped-nil)))))
+
+(define
+  go-numeric-name?
+  ;; Built-in numeric type names per Go spec § Numeric types.
+  (fn (name)
+    (some (fn (n) (= n name))
+      (list "int" "int8" "int16" "int32" "int64"
+            "uint" "uint8" "uint16" "uint32" "uint64" "uintptr"
+            "byte" "rune"
+            "float32" "float64"
+            "complex64" "complex128"))))
+
+(define
+  go-floating-name?
+  (fn (name)
+    (or (= name "float32") (= name "float64"))))
+
+(define
+  go-complex-name?
+  (fn (name)
+    (or (= name "complex64") (= name "complex128"))))
+
+(define
+  go-type-assignable?
+  ;; Can a value of type GOT be assigned to a slot of type EXPECTED?
+  ;; Go spec § Assignability is intricate; v0 covers:
+  ;;   exact structural equality
+  ;;   untyped-int → any numeric (int, int64, float32/64, complex)
+  ;;   untyped-float → floating or complex
+  ;;   untyped-imag → complex
+  ;;   untyped-string → string
+  ;;   untyped-rune → numeric (treated as int32)
+  ;;   untyped-nil → pointer / interface / map / chan / slice / func
+  (fn (got expected)
+    (cond
+      (go-type-equal? got expected) true
+      (and (list? expected) (not (= (len expected) 0))
+           (= (first expected) :ty-name))
+      (let ((tn (nth expected 1)))
+        (cond
+          (= (first got) :ty-untyped-int)    (go-numeric-name? tn)
+          (= (first got) :ty-untyped-float)
+          (or (go-floating-name? tn) (go-complex-name? tn))
+          (= (first got) :ty-untyped-imag)   (go-complex-name? tn)
+          (= (first got) :ty-untyped-rune)   (go-numeric-name? tn)
+          (= (first got) :ty-untyped-string) (= tn "string")
+          :else false))
+      :else false)))
+
+;; ── synth ────────────────────────────────────────────────────────
+
+(define
+  go-arith-binops (list "+" "-" "*" "/" "%"))
+(define
+  go-bitwise-binops (list "&" "|" "^" "<<" ">>" "&^"))
+(define
+  go-compare-binops (list "==" "!=" "<" "<=" ">" ">="))
+(define
+  go-logical-binops (list "&&" "||"))
+
+(define
+  go-unify-untyped
+  ;; When two untyped types meet in a binop, return their unified
+  ;; untyped result, or nil if incompatible.
+  (fn (a b)
+    (cond
+      (go-type-equal? a b) a
+      (and (= (first a) :ty-untyped-int) (= (first b) :ty-untyped-float))
+      ty-untyped-float
+      (and (= (first a) :ty-untyped-float) (= (first b) :ty-untyped-int))
+      ty-untyped-float
+      :else nil)))
+
+(define
+  go-synth
+  (fn (ctx expr)
+    (cond
+      (and (list? expr) (= (first expr) :literal))
+      (go-synth-literal (nth expr 1))
+      (and (list? expr) (= (first expr) :literal-string))
+      ty-untyped-string
+      (and (list? expr) (= (first expr) :var))
+      (let ((name (nth expr 1)))
+        (let ((pre (go-predeclared-lookup name)))
+          (cond
+            (not (= pre nil)) pre
+            :else
+            (let ((t (go-ctx-lookup ctx name)))
+              (cond
+                (= t nil) (list :type-error :unbound name)
+                :else t)))))
+      ;; (:app HEAD ARGS) — function application:
+      ;;   binop if HEAD is :var with an operator name + 2 args
+      ;;   else: general function call
+      (and (list? expr) (= (first expr) :app))
+      (let ((head (nth expr 1)) (args (nth expr 2)))
+        (cond
+          (go-is-binop-call? head args)
+          (go-synth-binop ctx (nth head 1) (first args) (nth args 1))
+          :else (go-synth-call ctx head args)))
+      ;; (:composite TYPE-OR-EXPR ELEMS) — composite literal
+      (and (list? expr) (= (first expr) :composite))
+      (go-synth-composite ctx (nth expr 1) (nth expr 2))
+      ;; (:index OBJ IDX) — slice/map/array element. v0: element type
+      ;; is the slice/array element type, or the map value type.
+      (and (list? expr) (= (first expr) :index))
+      (let ((obj-ty (go-synth ctx (nth expr 1))))
+        (cond
+          (go-type-error? obj-ty) obj-ty
+          (and (list? obj-ty) (= (first obj-ty) :ty-slice))
+          (nth obj-ty 1)
+          (and (list? obj-ty) (= (first obj-ty) :ty-array))
+          (nth obj-ty 2)
+          (and (list? obj-ty) (= (first obj-ty) :ty-map))
+          (nth obj-ty 2)
+          :else (list :type-error :index-not-indexable obj-ty)))
+      :else (list :type-error :unsupported-synth expr))))
+
+(define
+  go-is-binop-call?
+  (fn (head args)
+    (and (list? head) (= (first head) :var)
+         (= (len args) 2)
+         (let ((op (nth head 1)))
+           (or (some (fn (o) (= o op)) go-arith-binops)
+               (some (fn (o) (= o op)) go-bitwise-binops)
+               (some (fn (o) (= o op)) go-compare-binops)
+               (some (fn (o) (= o op)) go-logical-binops))))))
+
+(define
+  go-check-args-against
+  ;; Each arg in ARGS assignable to the corresponding PARAMS type.
+  ;; Caller already verified arities match.
+  (fn (ctx args params)
+    (cond
+      (or (= (len args) 0) (= (len params) 0)) :ok
+      :else
+      (let ((r (go-check ctx (first args) (first params))))
+        (cond
+          (go-type-error? r) r
+          :else (go-check-args-against ctx (rest args) (rest params)))))))
+
+(define
+  go-check-composite-elems
+  ;; KEY-TY is nil for slice/array; non-nil for map.
+  ;; For maps, each elem must be (:kv KEY VALUE) — KEY assignable to
+  ;; KEY-TY, VALUE to VAL-TY.
+  ;; For slice/array, plain exprs assignable to VAL-TY; (:kv K V) is
+  ;; Go's index-keyed shorthand (`[]int{0: 5, 1: 10}`) — we type-check
+  ;; only the value in v0.
+  (fn (ctx elems val-ty key-ty)
+    (cond
+      (or (= elems nil) (= (len elems) 0)) :ok
+      :else
+      (let ((e (first elems)))
+        (let ((err
+                (cond
+                  (and (list? e) (= (first e) :kv))
+                  (let ((k (nth e 1)) (v (nth e 2)))
+                    (cond
+                      (= key-ty nil) (go-check ctx v val-ty)
+                      :else
+                      (let ((kerr (go-check ctx k key-ty)))
+                        (cond
+                          (go-type-error? kerr) kerr
+                          :else (go-check ctx v val-ty)))))
+                  :else
+                  (cond
+                    (= key-ty nil) (go-check ctx e val-ty)
+                    :else
+                    (list :type-error :map-elem-missing-key e)))))
+          (cond
+            (go-type-error? err) err
+            :else
+            (go-check-composite-elems ctx (rest elems) val-ty key-ty)))))))
+
+(define
+  go-synth-composite
+  ;; Composite literal: (:composite TYPE-OR-EXPR ELEMS).
+  ;;   []T{...}            — each elem assignable to T; result :ty-slice T
+  ;;   [N]T{...}           — same; result :ty-array N T
+  ;;   map[K]V{...}        — each :kv key:K, value:V; result :ty-map K V
+  ;; Named-type literals (Point{...}, pkg.T{...}) require type-decl
+  ;; resolution; v0 returns the literal's type-expr as-is without
+  ;; element checking.
+  (fn (ctx ty elems)
+    (cond
+      (and (list? ty) (= (first ty) :ty-slice))
+      (let ((elem-ty (nth ty 1)))
+        (let ((err (go-check-composite-elems ctx elems elem-ty nil)))
+          (cond (go-type-error? err) err :else ty)))
+      (and (list? ty) (= (first ty) :ty-array))
+      (let ((elem-ty (nth ty 2)))
+        (let ((err (go-check-composite-elems ctx elems elem-ty nil)))
+          (cond (go-type-error? err) err :else ty)))
+      (and (list? ty) (= (first ty) :ty-map))
+      (let ((key-ty (nth ty 1)) (val-ty (nth ty 2)))
+        (let ((err (go-check-composite-elems ctx elems val-ty key-ty)))
+          (cond (go-type-error? err) err :else ty)))
+      :else ty)))
+
+(define
+  go-synth-call
+  ;; Synth a function call. Returns the result type, or :type-error.
+  ;;   0 results → (list :ty-void)
+  ;;   1 result  → that result type directly
+  ;;   N results → (list :ty-tuple TYPES) (multi-return)
+  (fn (ctx callee args)
+    (let ((fn-ty (go-synth ctx callee)))
+      (cond
+        (go-type-error? fn-ty) fn-ty
+        (not (and (list? fn-ty) (= (first fn-ty) :ty-func)))
+        (list :type-error :not-callable fn-ty)
+        :else
+        (let ((params (nth fn-ty 1)) (results (nth fn-ty 2)))
+          (cond
+            (not (= (len args) (len params)))
+            (list :type-error :arity-mismatch
+              (len params) (len args))
+            :else
+            (let ((err (go-check-args-against ctx args params)))
+              (cond
+                (go-type-error? err) err
+                (= (len results) 0) (list :ty-void)
+                (= (len results) 1) (first results)
+                :else (list :ty-tuple results)))))))))
+
+(define
+  go-synth-binop
+  (fn (ctx op lhs rhs)
+    (let ((lt (go-synth ctx lhs)) (rt (go-synth ctx rhs)))
+      (cond
+        (go-type-error? lt) lt
+        (go-type-error? rt) rt
+        ;; Comparison ops always produce bool (untyped-bool, simplified
+        ;; here to :ty-name "bool" until we model untyped-bool).
+        (some (fn (o) (= o op)) go-compare-binops)
+        (list :ty-name "bool")
+        (some (fn (o) (= o op)) go-logical-binops)
+        (list :ty-name "bool")
+        ;; Arithmetic / bitwise: types must unify.
+        (or (some (fn (o) (= o op)) go-arith-binops)
+            (some (fn (o) (= o op)) go-bitwise-binops))
+        (cond
+          (and (go-untyped? lt) (go-untyped? rt))
+          (let ((unified (go-unify-untyped lt rt)))
+            (cond
+              (= unified nil)
+              (list :type-error :binop-untyped-mismatch op lt rt)
+              :else unified))
+          (and (go-untyped? lt) (not (go-untyped? rt)))
+          (cond
+            (go-type-assignable? lt rt) rt
+            :else (list :type-error :binop-mismatch op lt rt))
+          (and (not (go-untyped? lt)) (go-untyped? rt))
+          (cond
+            (go-type-assignable? rt lt) lt
+            :else (list :type-error :binop-mismatch op lt rt))
+          (go-type-equal? lt rt) lt
+          :else (list :type-error :binop-mismatch op lt rt))
+        :else (list :type-error :unsupported-binop op)))))
+
+;; ── check ────────────────────────────────────────────────────────
+
+(define
+  go-check
+  (fn
+    (ctx expr expected)
+    (let
+      ((got (go-synth ctx expr)))
+      (cond
+        (go-type-error? got)
+        got
+        (go-type-assignable? got expected)
+        :ok :else
+        (list :type-error :mismatch expected got)))))
+
+;; ── default types ────────────────────────────────────────────────
+;; Go spec § Constants: the *default type* of an untyped constant
+;; is what it becomes when assigned to a sloppily-typed slot
+;; (e.g., `var x = 42` makes x an int).
+
+(define
+  go-default-type
+  (fn (t)
+    (cond
+      (not (list? t)) t
+      (= (first t) :ty-untyped-int)    (list :ty-name "int")
+      (= (first t) :ty-untyped-float)  (list :ty-name "float64")
+      (= (first t) :ty-untyped-imag)   (list :ty-name "complex128")
+      (= (first t) :ty-untyped-string) (list :ty-name "string")
+      (= (first t) :ty-untyped-rune)   (list :ty-name "int32")
+      :else t)))
+
+;; ── declaration checking ────────────────────────────────────────
+;; Returns either:
+;;   the extended context (success)
+;;   (list :type-error TAG ...) (failure)
+
+(define
+  go-check-exprs-against
+  ;; Check every EXPR in EXPRS is assignable to EXPECTED. Returns the
+  ;; first :type-error encountered, or :ok.
+  (fn (ctx exprs expected)
+    (cond
+      (or (= exprs nil) (= (len exprs) 0)) :ok
+      :else
+      (let ((r (go-check ctx (first exprs) expected)))
+        (cond
+          (go-type-error? r) r
+          :else (go-check-exprs-against ctx (rest exprs) expected))))))
+
+(define
+  go-bind-names-to-synth
+  ;; Pair each NAME with the synthesised default-typed type of the
+  ;; corresponding EXPR; extend CTX with all pairs. NAMES and EXPRS
+  ;; may have different lengths (multi-return funcs aren't here yet);
+  ;; for now we zip the shorter of the two.
+  (fn (ctx names exprs)
+    (cond
+      (or (= (len names) 0) (= (len exprs) 0)) ctx
+      :else
+      (let ((t (go-synth ctx (first exprs))))
+        (cond
+          (go-type-error? t) t
+          :else
+          (let ((ctx2 (go-ctx-extend ctx (first names)
+                       (go-default-type t))))
+            (go-bind-names-to-synth ctx2 (rest names) (rest exprs))))))))
+
+(define
+  go-check-var-decl
+  ;; Shape: (:var-decl (:field NAMES TYPE-or-nil) EXPRS-or-nil)
+  ;; or     (:const-decl (:field NAMES TYPE-or-nil) EXPRS).
+  ;; Logic is the same for v0; const-vs-var distinction matters for
+  ;; mutability checks which arrive later.
+  (fn (ctx decl)
+    (let ((field (nth decl 1)) (exprs (nth decl 2)))
+      (let ((names (nth field 1)) (ann-ty (nth field 2)))
+        (cond
+          ;; var x T (no init) → bind names to T
+          (or (= exprs nil) (= (len exprs) 0))
+          (cond
+            (= ann-ty nil) (list :type-error :missing-type-or-init names)
+            :else (go-ctx-extend-field ctx field))
+          ;; Annotated: var x T = expr — check each expr against T
+          (not (= ann-ty nil))
+          (let ((err (go-check-exprs-against ctx exprs ann-ty)))
+            (cond
+              (go-type-error? err) err
+              :else (go-ctx-extend-field ctx field)))
+          ;; Inferred: var x = expr — bind names to default(synth(expr))
+          :else (go-bind-names-to-synth ctx names exprs))))))
+
+(define
+  go-check-short-decl
+  ;; Shape: (:short-decl LHS-LIST EXPRS). LHS is a list of (:var NAME).
+  ;; Extracts the names and falls through to bind-names-to-synth.
+  (fn (ctx decl)
+    (let ((lhs-list (nth decl 1)) (exprs (nth decl 2)))
+      (let ((names (map (fn (lhs)
+                          (cond
+                            (and (list? lhs) (= (first lhs) :var))
+                            (nth lhs 1)
+                            :else :unknown))
+                        lhs-list)))
+        (go-bind-names-to-synth ctx names exprs)))))
+
+(define
+  go-check-decl
+  ;; Top-level dispatcher: accepts any decl AST shape, returns extended
+  ;; context or :type-error.
+  (fn (ctx decl)
+    (cond
+      (and (list? decl) (= (first decl) :var-decl))   (go-check-var-decl ctx decl)
+      (and (list? decl) (= (first decl) :const-decl)) (go-check-var-decl ctx decl)
+      (and (list? decl) (= (first decl) :short-decl)) (go-check-short-decl ctx decl)
+      (and (list? decl) (= (first decl) :type-decl))
+      (let ((name (nth decl 1)) (ty (nth decl 2)))
+        (go-ctx-extend ctx name ty))
+      (and (list? decl) (= (first decl) :func-decl))
+      (go-check-func-decl ctx decl)
+      (and (list? decl) (= (first decl) :method-decl))
+      (go-check-method-decl ctx decl)
+      :else ctx)))
+
+;; ── method declarations and interface satisfaction ──────────────
+;; Methods are recorded in CTX under a mangled key
+;;   "#method/RECV-TYPE-NAME/METHOD-NAME"
+;; bound to the method's :ty-func signature. Interface satisfaction is
+;; a structural lookup over these keys (Go spec § Interface types:
+;; "anything with the matching method set satisfies the interface").
+
+(define
+  go-method-key
+  (fn (recv-ty-name method-name)
+    (str "#method/" recv-ty-name "/" method-name)))
+
+(define
+  go-extract-recv-ty-name
+  ;; Receiver type is T or *T; return the named type's name string.
+  (fn (recv-ty)
+    (cond
+      (and (list? recv-ty) (= (first recv-ty) :ty-name))
+      (nth recv-ty 1)
+      (and (list? recv-ty) (= (first recv-ty) :ty-ptr))
+      (go-extract-recv-ty-name (nth recv-ty 1))
+      :else nil)))
+
+(define
+  go-check-method-decl
+  ;; (list :method-decl RECV NAME PARAMS RESULTS BODY)
+  ;; Binds the method under the mangled key, then checks body with
+  ;; receiver + params extended.
+  (fn (ctx decl)
+    (let ((recv (nth decl 1)) (name (nth decl 2))
+          (params (nth decl 3)) (results (nth decl 4))
+          (body (nth decl 5)))
+      (let ((recv-ty (nth recv 2)))
+        (let ((recv-name (go-extract-recv-ty-name recv-ty)))
+          (let ((sig (list :ty-func
+                       (go-decl-params-to-ty-list params) results)))
+            (let ((ctx2
+                    (cond
+                      (= recv-name nil) ctx
+                      :else
+                      (go-ctx-extend ctx
+                        (go-method-key recv-name name) sig))))
+              (cond
+                (= body nil) ctx2
+                (and (list? body) (= (first body) :block))
+                (let ((body-ctx
+                        (go-extend-with-params
+                          (go-ctx-extend-field ctx2 recv) params)))
+                  (let ((err
+                          (go-check-block body-ctx
+                            (nth body 1) results)))
+                    (cond
+                      (go-type-error? err) err
+                      :else ctx2)))
+                :else ctx2))))))))
+
+(define
+  go-iface-elems-satisfied?
+  ;; Each :method element in ELEMS must have a matching method in CTX
+  ;; under #method/TY-NAME/M-NAME. :embed elements are skipped in v0
+  ;; (they'd need recursive interface resolution).
+  (fn (ctx ty-name elems)
+    (cond
+      (= (len elems) 0) true
+      :else
+      (let ((e (first elems)))
+        (cond
+          (= (first e) :method)
+          (let ((m-name (nth e 1)) (m-params (nth e 2))
+                (m-results (nth e 3)))
+            (let ((found (go-ctx-lookup ctx
+                           (go-method-key ty-name m-name))))
+              (cond
+                (= found nil) false
+                (and (= (nth found 1) m-params)
+                     (= (nth found 2) m-results))
+                (go-iface-elems-satisfied? ctx ty-name (rest elems))
+                :else false)))
+          (= (first e) :embed)
+          (go-iface-elems-satisfied? ctx ty-name (rest elems))
+          :else
+          (go-iface-elems-satisfied? ctx ty-name (rest elems)))))))
+
+(define
+  go-iface-satisfies?
+  ;; Does the type named TY-NAME satisfy the interface IFACE-TYPE
+  ;; under context CTX? Structural method-set match per Go spec.
+  (fn (ctx ty-name iface-type)
+    (cond
+      (not (and (list? iface-type) (= (first iface-type) :ty-interface)))
+      false
+      :else (go-iface-elems-satisfied? ctx ty-name (nth iface-type 1)))))
+
+;; ── function-decl checking ──────────────────────────────────────
+
+(define
+  go-repeat-ty
+  (fn (n ty acc)
+    (cond
+      (<= n 0) acc
+      :else (go-repeat-ty (- n 1) ty (cons ty acc)))))
+
+(define
+  go-decl-params-to-ty-list
+  ;; Flatten (:field NAMES TYPE) param groups into a list of types,
+  ;; one entry per name. For func-type signatures.
+  (fn (params)
+    (cond
+      (or (= params nil) (= (len params) 0)) (list)
+      :else
+      (let ((field (first params)))
+        (let ((names (nth field 1)) (ty (nth field 2)))
+          (let ((rest-tys (go-decl-params-to-ty-list (rest params))))
+            (go-repeat-ty (len names) ty rest-tys)))))))
+
+(define
+  go-extend-with-params
+  ;; Extend CTX with every binding in every (:field NAMES TYPE) param group.
+  (fn (ctx params)
+    (cond
+      (or (= params nil) (= (len params) 0)) ctx
+      :else
+      (go-extend-with-params
+        (go-ctx-extend-field ctx (first params))
+        (rest params)))))
+
+(define
+  go-check-return-list
+  ;; Each EXPR assignable to the corresponding RESULTS type.
+  ;; v0: lengths must match; multi-return funcs deferred.
+  (fn (ctx exprs results)
+    (cond
+      (and (= (len exprs) 0) (= (len results) 0)) :ok
+      (not (= (len exprs) (len results)))
+      (list :type-error :return-count-mismatch
+        (len exprs) (len results))
+      :else
+      (let ((r (go-check ctx (first exprs) (first results))))
+        (cond
+          (go-type-error? r) r
+          :else (go-check-return-list ctx (rest exprs) (rest results)))))))
+
+(define
+  go-check-assign
+  (fn (ctx stmt)
+    (let ((lhs-list (nth stmt 1)) (rhs-list (nth stmt 2)))
+      (cond
+        (not (= (len lhs-list) (len rhs-list)))
+        (list :type-error :assign-count-mismatch
+          (len lhs-list) (len rhs-list))
+        :else (go-check-assign-pairs ctx lhs-list rhs-list)))))
+
+(define
+  go-check-assign-pairs
+  (fn (ctx lhs-list rhs-list)
+    (cond
+      (= (len lhs-list) 0) :ok
+      :else
+      (let ((lhs-ty (go-synth ctx (first lhs-list))))
+        (cond
+          (go-type-error? lhs-ty) lhs-ty
+          :else
+          (let ((r (go-check ctx (first rhs-list) lhs-ty)))
+            (cond
+              (go-type-error? r) r
+              :else
+              (go-check-assign-pairs ctx (rest lhs-list)
+                (rest rhs-list)))))))))
+
+(define
+  go-check-stmt
+  ;; Returns either an extended CTX (decls), :ok (sealed stmts), or
+  ;; :type-error. RESULTS is the enclosing func's declared return types
+  ;; (used by :return).
+  (fn (ctx stmt results)
+    (cond
+      (and (list? stmt) (= (first stmt) :var-decl))
+      (go-check-decl ctx stmt)
+      (and (list? stmt) (= (first stmt) :const-decl))
+      (go-check-decl ctx stmt)
+      (and (list? stmt) (= (first stmt) :short-decl))
+      (go-check-decl ctx stmt)
+      (and (list? stmt) (= (first stmt) :type-decl))
+      (go-check-decl ctx stmt)
+      (and (list? stmt) (= (first stmt) :return))
+      (let ((exprs (nth stmt 1)))
+        (let ((err (go-check-return-list ctx exprs results)))
+          (cond (go-type-error? err) err :else ctx)))
+      (and (list? stmt) (= (first stmt) :block))
+      (let ((err (go-check-block ctx (nth stmt 1) results)))
+        (cond (go-type-error? err) err :else ctx))
+      (and (list? stmt) (= (first stmt) :assign))
+      (let ((err (go-check-assign ctx stmt)))
+        (cond (go-type-error? err) err :else ctx))
+      :else
+      (let ((t (go-synth ctx stmt)))
+        (cond (go-type-error? t) t :else ctx)))))
+
+(define
+  go-check-block
+  ;; Thread ctx through stmts; if any stmt is a decl, its extension
+  ;; propagates to subsequent stmts. Returns :ok or :type-error.
+  (fn (ctx stmts results)
+    (cond
+      (or (= stmts nil) (= (len stmts) 0)) :ok
+      :else
+      (let ((r (go-check-stmt ctx (first stmts) results)))
+        (cond
+          (go-type-error? r) r
+          :else (go-check-block r (rest stmts) results))))))
+
+(define
+  go-check-func-decl
+  ;; Bind the function in the outer ctx (so recursion works), extend
+  ;; ctx with type params + value params, check the body. Returns the
+  ;; outer ctx with the function bound, or :type-error.
+  ;;
+  ;; Type parameters become opaque type variables in the body's ctx:
+  ;; each name `T` is bound as a type alias to (:ty-param "T") so the
+  ;; checker treats references to T as "this type", not "unknown".
+  ;; Constraint enforcement (T satisfies `comparable` etc.) is a
+  ;; later refinement; v0 just allows any operation that's polymorphic
+  ;; under the constraint `any`.
+  (fn (ctx decl)
+    (let ((name (nth decl 1)) (params (nth decl 2))
+          (results (nth decl 3)) (body (nth decl 4))
+          (type-params (cond (> (len decl) 5) (nth decl 5) :else nil)))
+      (let ((fn-ty
+              (list :ty-func
+                (go-decl-params-to-ty-list params) results)))
+        (let ((ctx-with-fn (go-ctx-extend ctx name fn-ty)))
+          (cond
+            (= body nil) ctx-with-fn
+            (and (list? body) (= (first body) :block))
+            (let ((body-ctx
+                    (go-extend-with-type-params
+                      (go-extend-with-params ctx-with-fn params)
+                      type-params)))
+              (let ((err
+                      (go-check-block body-ctx (nth body 1) results)))
+                (cond
+                  (go-type-error? err) err
+                  :else ctx-with-fn)))
+            :else ctx-with-fn))))))
+
+(define
+  go-extend-with-type-params
+  ;; Each (:field NAMES CONSTRAINT) field contributes opaque type
+  ;; vars: bind each NAME as a type alias to (:ty-param NAME). The
+  ;; constraint type is stored alongside so future "constraint
+  ;; satisfaction" checks can find it; for v0 it's informational.
+  (fn (ctx type-params)
+    (cond
+      (or (= type-params nil) (= (len type-params) 0)) ctx
+      :else
+      (let ((field (first type-params)))
+        (let ((names (nth field 1)) (constraint (nth field 2)))
+          (go-extend-with-type-params
+            (go-extend-with-type-param-names ctx names constraint)
+            (rest type-params)))))))
+
+(define
+  go-extend-with-type-param-names
+  (fn (ctx names constraint)
+    (cond
+      (= (len names) 0) ctx
+      :else
+      (let ((nm (first names)))
+        (go-extend-with-type-param-names
+          (go-ctx-extend ctx nm
+            (list :ty-param nm constraint))
+          (rest names) constraint)))))

next/.gitignore

@@ -1 +0,0 @@
-data/

next/README.md

@@ -1,170 +0,0 @@
-# next — fed-sx Milestone 1 kernel
-
-Single-instance, single-actor fed-sx server built as Erlang-on-SX modules.
-See `plans/fed-sx-design.md` for the architecture and
-`plans/fed-sx-milestone-1.md` for the build plan + per-step progress log.
-
-## Status
-
-Both Step 9 smoke proof points are functional **in-process**:
-
-- **9a-pure (verb extensibility)** — `Create{DefineActivity{Pin}}` registers Pin
-  at runtime; subsequent `Pin{path, cid}` activities fold into a pin-state
-  projection. Zero kernel code between definition and use.
-  See `next/tests/smoke_pin_pure.sh`.
-- **9b-pure (reactive application)** — A trigger projection matches Notes
-  tagged `smoketest` and derives a `TestEcho` carrying the source CID.
-  See `next/tests/smoke_app_pure.sh`.
-
-The remaining `9a-tcp` / `9b-tcp` deliverables layer TCP transport on top — see
-*Substrate gaps* below.
-
-## Layout
-
-```
-next/
-├── kernel/      Erlang-on-SX kernel modules (.erl)
-├── genesis/     SX source files for the bootstrap bundle
-├── tests/       Bash test scripts driving sx_server.exe via the epoch protocol
-└── data/        Runtime state — gitignored
-```
-
-## Module map
-
-| Module                | Role                                                                   |
-|-----------------------|------------------------------------------------------------------------|
-| `nx_cid.erl`          | Canonical CID wrapper around the host `cid:to_string` BIF              |
-| `envelope.erl`        | Activity envelope shape, canonical bytes, time-aware sig verify        |
-| `log.erl`             | Per-actor in-memory append log (open / append / tip / replay / entries) |
-| `registry.erl`        | Pure-functional + gen_server-wrapped registry keyed by Kind             |
-| `pipeline.erl`        | Validation driver + stage_envelope/signature/replay/schema             |
-| `projection.erl`      | Pure projection driver + gen_server-per-projection wrapper             |
-| `outbox.erl`          | Envelope construct + sign + publish orchestrator + broadcast            |
-| `bootstrap.erl`       | Genesis read/build/verify/load + one-call `start/3` kernel bring-up    |
-| `define_registry.erl` | Meta-projection fold for `Create{Define*}` → registry                  |
-| `sandbox.erl`         | `eval_pure/2,3` try/catch envelope for projection folds                |
-| `nx_kernel.erl`       | Long-lived runtime orchestrator (state + gen_server)                    |
-| `http_server.erl`     | route/1,2 + format-aware GET + POST + Accept header content negotiation |
-
-## Genesis bundle
-
-`next/genesis/` contains 31 SX files across 7 sections, all consumed as data
-(read + serialised by `bootstrap:populate_registry`, not eval'd):
-
-- 3 activity-types — Create, Update, Delete
-- 10 object-types — SXArtifact, Note, Tombstone, 6 Define* meta-types, Snapshot
-- 7 projections — activity-log, by-type, by-actor, by-object, actor-state,
-  define-registry, audience-graph
-- 3 validators — envelope-shape, signature, type-schema
-- 3 codecs — dag-cbor, raw, dag-json
-- 2 sig-suites — rsa-sha256-2018, ed25519-2020
-- 3 audience predicates — Public, Followers, Direct
-
-`manifest.sx` is the bundle root, listed in dependency-friendly order.
-
-## Tests
-
-43 test suites, ~560+ assertions. Each script drives `sx_server.exe` via the
-epoch protocol — loads the Erlang substrate, loads relevant kernel modules
-via `code:load_binary` / `erlang-load-module`, then exercises behaviour
-through `erlang-eval-ast`.
-
-Conventions:
-
-- Scripts marked `_pure.sh` exercise pure-functional state.
-- Scripts marked `_server.sh` (or no suffix) exercise gen_server APIs and
-  must inline `start_link` with operations — the Erlang-on-SX scheduler
-  doesn't preserve spawned processes across separate `erlang-eval-ast`
-  invocations.
-- `smoke_*_pure.sh` are end-to-end smoke tests demonstrating the §Step 9
-  proof points without TCP / curl / JSON.
-
-The Erlang-on-SX conformance gate (`bash lib/erlang/conformance.sh`, **729 /
-729**) is the no-regression contract — every commit on `loops/fed-sx-m1`
-preserves it.
-
-## Substrate
-
-Each `.erl` source file is hot-loaded at boot via
-`code:load_binary(Mod, Filename, SourceString)` (Phase 7 BIF). Tests drive
-the runtime via the epoch protocol:
-
-```bash
-printf '(epoch 1)\n(load "lib/erlang/runtime.sx")\n(epoch 2)\n<test-expr>\n' \
-  | hosts/ocaml/_build/default/bin/sx_server.exe
-```
-
-The kernel calls into these host primitives: `crypto:hash/2`,
-`cid:from_bytes/1`, `cid:to_string/1`, `file:read_file/1`, `file:write_file/2`,
-`file:delete/1`, `file:list_dir/1`, `code:load_binary/3`, plus `http:listen/2`
-(the briefing's allowed scope exception, added to `lib/erlang/runtime.sx`).
-
-### Substrate gaps (parked work)
-
-These three gaps block the remaining unchecked deliverables:
-
-1. **Term codec** (`3b`/`3c`) — **all three substrate fixes done 2026-06-05:**
-   `erlang:binary_to_list/1` and `erlang:list_to_binary/1` registered in
-   `lib/erlang/runtime.sx` (iolist-aware); the tokenizer's `$X` branch
-   emits the decimal char code; `atom_to_list/1` and `integer_to_list/1`
-   now return Erlang charlists (standard Erlang semantics) with `list_to_atom`/
-   `list_to_integer` accepting both charlists and SX strings for back-compat.
-   759/759 conformance. The full term-codec primitive set is in place —
-   Step 3b on-disk segment writer can encode arbitrary Erlang activity
-   terms (atoms, ints, binaries, tuples, lists) into byte sequences using
-   only Erlang-native primitives.
-
-2. **SX-source eval bridge** — There's no BIF that lets Erlang call into the
-   SX evaluator on a parsed source string. Blocks evaluating the `:schema` /
-   `:fold` / `:predicate` / `:verify` bodies from the genesis bundle. Erlang-fun
-   stand-ins (`pipeline:stage_schema`, `define_registry:fold`, etc.) prove the
-   API shapes; the bridge would let bundle bodies dispatch through them
-   unchanged.
-
-3. **Dict ↔ proplist marshalling for `http:listen/2`** — **done 2026-06-05.**
-   `er-bif-http-listen` marshals the native server's request dict
-   (`{:method :path :query :headers :body}`) into the proplist shape
-   `[{method, Bin}, {path, Bin}, {query, Bin}, {headers, [{Name, Value}]},
-   {body, Bin}]` that `http_server:route/2` consumes, and converts the
-   handler's response proplist back to `{:status :headers :body}` for the
-   native server to serialise. Helpers (`er-request-dict-to-proplist`,
-   `er-proplist-to-dict`, `er-of-sx-deep`, `er-to-sx-deep`,
-   `er-dict-to-header-proplist`, `er-proplist-fill!`) live alongside the
-   BIF wrapper in `lib/erlang/runtime.sx`. The BIF also spawns the handler
-   into a real Erlang process via `er-spawn-fun` + `er-sched-run-all!`
-   so `self()` / `gen_server:call` work inside route handlers (the kernel
-   and projection gen_servers reach the handler this way). Verified by
-   `next/tests/http_marshal.sh` and the live TCP smoke
-   `next/tests/http_server_tcp.sh` / `http_server_start.sh`. Unblocks
-   `Step 8b-start` (TCP listener spawn) and the curl-driven 9a-tcp / 9b-tcp
-   smoke tests.
-
-### Bringing up the kernel
-
-For tests, `bootstrap:start/3(ActorId, KeySpec, ActorState)` is the
-one-call boot:
-
-```erlang
-KM = <<1,2,3,4>>,
-KS = [{key_id, k1}, {algorithm, ed25519}, {value, KM}],
-AS = [{public_keys, [[{id, k1}, {created, 0}, {value, KM}]]}],
-Pid = bootstrap:start(alice, KS, AS),
-%% nx_kernel + registry populated; you now have a kernel.
-```
-
-The HTTP layer (`http_server`) and `nx_kernel:publish/1` flow through the
-same in-process gen_servers; `http_publish_fold.sh` is the end-to-end proof
-the chain works.
-
-## What's next (when work resumes)
-
-In priority order:
-
-1. **8b-start** — `http_server:start/1` spawns a process hosting `http:listen/2`.
-   (8b-bridge done — see Substrate gap #3.)
-2. **9a-tcp / 9b-tcp** — replace the in-process smoke scripts with curl-driven
-   versions hitting the running server.
-3. **Term codec / on-disk log** — needs either a new BIF or a temp-file
-   workaround; current in-memory log keeps everything functional otherwise.
-4. **SX-source eval bridge** — unlocks real `:schema` / `:fold` body
-   evaluation from the genesis bundle.

next/genesis/activity-types/create.sx

@@ -1,15 +0,0 @@
-;; next/genesis/activity-types/create.sx
-;;
-;; Bootstrap definition of the Create verb per design §3 and §12.2.
-;; Read as data by the bundler (bootstrap.erl) — never evaluated as
-;; code. The :schema and :semantics bodies are SX source; the
-;; validation pipeline (Step 6) and projection scheduler (Step 7)
-;; evaluate them at the appropriate times.
-
-(DefineActivity
-  :name "Create"
-  :doc "Publish a new object. Required for actor onboarding and for\n        every Define* meta-activity. The activity's :object holds\n        the canonical content of the published object."
-  :schema (fn
-    (act)
-    (and (not (nil? (-> act :object))) (string? (-> act :object :type))))
-  :semantics (fn (state act) state))

next/genesis/activity-types/delete.sx

@@ -1,13 +0,0 @@
-;; next/genesis/activity-types/delete.sx
-;;
-;; Bootstrap definition of the Delete verb per design §3 and §12.2.
-;; Read as data by the bundler — never evaluated as code here. The
-;; :schema and :semantics bodies are SX source; the validator
-;; pipeline (Step 6) and projection scheduler (Step 7) evaluate them
-;; at the appropriate times.
-
-(DefineActivity
-  :name "Delete"
-  :doc "Tombstone an existing object. :object is the CID of the\n        target. Projections fold Delete by removing the object from\n        their working indexes; the underlying log line is never\n        erased — durability of the historical record is independent\n        of projection state."
-  :schema (fn (act) (string? (-> act :object)))
-  :semantics (fn (state act) state))

next/genesis/activity-types/update.sx

@@ -1,15 +0,0 @@
-;; next/genesis/activity-types/update.sx
-;;
-;; Bootstrap definition of the Update verb per design §3 and §12.2.
-;; Read as data by the bundler — never evaluated as code here. The
-;; :schema and :semantics bodies are SX source; the validator
-;; pipeline (Step 6) and projection scheduler (Step 7) evaluate them
-;; at the appropriate times.
-
-(DefineActivity
-  :name "Update"
-  :doc "Patch or replace an existing object. :object is the CID of\n        the target; :patch is the field-level edit. Behaviour is\n        delegated to per-object-type semantics — e.g. an Update of a\n        DefineActivity supersedes the prior registry entry; an\n        Update of a Person actor rotates keys via :patch :add-publicKey\n        + :patch :supersede."
-  :schema (fn
-    (act)
-    (and (string? (-> act :object)) (not (nil? (-> act :patch)))))
-  :semantics (fn (state act) state))

next/genesis/audience/direct.sx

@@ -1,14 +0,0 @@
-;; next/genesis/audience/direct.sx
-;;
-;; Direct audience: an actor is a member iff they are
-;; explicitly named in the activity's :to or :cc lists. No
-;; group expansion — true direct addressing only.
-
-(DefineAudience
-  :name "Direct"
-  :doc "Direct-addressing predicate. Tests literal membership\n        in the activity's :to or :cc."
-  :member-of (fn
-    (actor audience)
-    (or
-      (member? actor (-> audience :to))
-      (member? actor (-> audience :cc)))))

next/genesis/audience/followers.sx

@@ -1,14 +0,0 @@
-;; next/genesis/audience/followers.sx
-;;
-;; Followers audience: an actor is a member iff they appear in
-;; the audience-owner's :followers set in the audience-graph
-;; projection. Federation (m2) wires this to peer delivery.
-
-(DefineAudience
-  :name "Followers"
-  :doc "Followers-of-owner predicate. Looks up the\n        audience-graph projection's :followers list for the\n        audience owner and tests membership."
-  :member-of (fn
-    (actor audience)
-    (member?
-      actor
-      (-> (get-projection :audience-graph) (-> audience :owner) :followers))))

next/genesis/audience/public.sx

@@ -1,9 +0,0 @@
-;; next/genesis/audience/public.sx
-;;
-;; Public audience: every actor is a member. Maps to the AP
-;; magic id `https://www.w3.org/ns/activitystreams#Public`.
-
-(DefineAudience
-  :name "Public"
-  :doc "Public audience predicate. Always returns true — every\n        actor on the network is considered a member."
-  :member-of (fn (actor audience) true))

next/genesis/codecs/dag-cbor.sx

@@ -1,13 +0,0 @@
-;; next/genesis/codecs/dag-cbor.sx
-;;
-;; Canonical CBOR encoding per IPLD dag-cbor. Used to compute
-;; envelope canonical bytes for signature coverage and to serialise
-;; the genesis bundle itself. In Erlang-on-SX mode the kernel
-;; dispatches to the host cid:to_string substrate (Step 1b) when
-;; this codec is requested.
-
-(DefineCodec
-  :name "dag-cbor"
-  :doc "Deterministic CBOR with dag-cbor restrictions: sorted\n        map keys, no floats unless required, no indefinite-length\n        items. The canonical wire format for fed-sx artifacts."
-  :encode (fn (term) (host-codec :dag-cbor :encode term))
-  :decode (fn (bytes) (host-codec :dag-cbor :decode bytes)))

next/genesis/codecs/dag-json.sx

@@ -1,12 +0,0 @@
-;; next/genesis/codecs/dag-json.sx
-;;
-;; JSON encoding with dag-json restrictions per IPLD: sorted map
-;; keys, no NaN / Infinity, no comments, CIDs as `{"/": "..."}`.
-;; Used as the human-readable wire format for ActivityPub interop
-;; (JSON-LD over dag-json).
-
-(DefineCodec
-  :name "dag-json"
-  :doc "Deterministic JSON with dag-json restrictions. Sorted\n        keys, CIDs as the {\"/\": \"...\"} object. Used by the\n        HTTP server (Step 8) for application/json responses."
-  :encode (fn (term) (host-codec :dag-json :encode term))
-  :decode (fn (bytes) (host-codec :dag-json :decode bytes)))

next/genesis/codecs/raw.sx

@@ -1,12 +0,0 @@
-;; next/genesis/codecs/raw.sx
-;;
-;; Identity codec — input bytes pass through unchanged in both
-;; directions. Used for already-encoded payloads and for binary
-;; artifacts (images, archives) whose CID is computed over the
-;; raw bytes directly.
-
-(DefineCodec
-  :name "raw"
-  :doc "Identity codec. The CID's multicodec byte is 0x55.\n        :encode and :decode return their input unchanged."
-  :encode (fn (bytes) bytes)
-  :decode (fn (bytes) bytes))

next/genesis/manifest.sx

@@ -1,46 +0,0 @@
-;; next/genesis/manifest.sx
-;;
-;; Genesis bundle root per design §12.2. Lists every definition file
-;; that gets packed into the bundle. The bundler (bootstrap.erl)
-;; walks this manifest, reads each referenced file, parses its
-;; top-level form, and inserts it into the bundle dict at the
-;; appropriate section path.
-;;
-;; The bundle CID is the content-address of the resulting dag-cbor
-;; (or v1 stand-in) blob over the assembled dict. That CID is
-;; baked into the kernel at build time and re-verified on startup
-;; per design §12.3.
-;;
-;; Section values are bare parenthesised paths (data lists, not
-;; function calls) — the manifest is consumed by `parse`, not
-;; `eval`. Empty sections are written as `()`.
-
-(GenesisManifest
-  :version "0.0.1"
-  :kernel-version "1.0.0-m1"
-  :activity-types ("activity-types/create.sx"
-    "activity-types/update.sx"
-    "activity-types/delete.sx")
-  :object-types ("object-types/sx-artifact.sx"
-    "object-types/note.sx"
-    "object-types/tombstone.sx"
-    "object-types/define-activity.sx"
-    "object-types/define-object.sx"
-    "object-types/define-projection.sx"
-    "object-types/define-validator.sx"
-    "object-types/define-codec.sx"
-    "object-types/define-sig-suite.sx"
-    "object-types/snapshot.sx")
-  :projections ("projections/activity-log.sx"
-    "projections/by-type.sx"
-    "projections/by-actor.sx"
-    "projections/by-object.sx"
-    "projections/actor-state.sx"
-    "projections/define-registry.sx"
-    "projections/audience-graph.sx")
-  :validators ("validators/envelope-shape.sx"
-    "validators/signature.sx"
-    "validators/type-schema.sx")
-  :codecs ("codecs/dag-cbor.sx" "codecs/raw.sx" "codecs/dag-json.sx")
-  :sig-suites ("sig-suites/rsa-sha256-2018.sx" "sig-suites/ed25519-2020.sx")
-  :audience ("audience/public.sx" "audience/followers.sx" "audience/direct.sx"))

next/genesis/object-types/define-activity.sx

@@ -1,12 +0,0 @@
-;; next/genesis/object-types/define-activity.sx
-;;
-;; Meta-object that registers a new activity verb. Published as
-;; Create{DefineActivity{...}}; the define-registry projection
-;; folds it into the activity-types registry. Per design §5.
-
-(DefineObject
-  :name "DefineActivity"
-  :doc "Activity-type registration. :name is the verb (e.g.\n        \"Pin\"); :schema is an SX predicate over activity\n        envelopes; :semantics is an optional state-fold body."
-  :schema (fn
-    (obj)
-    (and (string? (-> obj :name)) (not (nil? (-> obj :schema))))))

next/genesis/object-types/define-codec.sx

@@ -1,15 +0,0 @@
-;; next/genesis/object-types/define-codec.sx
-;;
-;; Meta-object that registers a content codec — an encode/decode
-;; pair. The bootstrap bundle ships dag-cbor, raw, and dag-json
-;; codecs; new codecs can be added via Create{DefineCodec{...}}.
-
-(DefineObject
-  :name "DefineCodec"
-  :doc "Codec registration. :name identifies the codec ('dag-cbor',\n        'raw', 'dag-json', ...); :encode and :decode are the\n        SX bodies the kernel calls when serialising / parsing\n        artifacts under this codec."
-  :schema (fn
-    (obj)
-    (and
-      (string? (-> obj :name))
-      (not (nil? (-> obj :encode)))
-      (not (nil? (-> obj :decode))))))

next/genesis/object-types/define-object.sx

@@ -1,12 +0,0 @@
-;; next/genesis/object-types/define-object.sx
-;;
-;; Meta-object that registers a new object-type. Bootstrap-level —
-;; runtime registration of new object types (e.g. DefineSubscription
-;; in the Step 9b smoke test) flows through this.
-
-(DefineObject
-  :name "DefineObject"
-  :doc "Object-type registration. :name is the type tag (e.g.\n        \"PinSpec\"); :schema is an SX predicate over object\n        forms of that type."
-  :schema (fn
-    (obj)
-    (and (string? (-> obj :name)) (not (nil? (-> obj :schema))))))

next/genesis/object-types/define-projection.sx

@@ -1,16 +0,0 @@
-;; next/genesis/object-types/define-projection.sx
-;;
-;; Meta-object that registers a new projection. The projection
-;; scheduler (Step 7) spawns one gen_server per registered
-;; projection and feeds activities through its :fold body in
-;; sandbox mode.
-
-(DefineObject
-  :name "DefineProjection"
-  :doc "Projection registration. :name is the projection key;\n        :initial-state is the empty state value; :fold is the\n        pure (state activity) -> state function evaluated in\n        sandbox mode per activity."
-  :schema (fn
-    (obj)
-    (and
-      (string? (-> obj :name))
-      (not (nil? (-> obj :initial-state)))
-      (not (nil? (-> obj :fold))))))

next/genesis/object-types/define-sig-suite.sx

@@ -1,12 +0,0 @@
-;; next/genesis/object-types/define-sig-suite.sx
-;;
-;; Meta-object that registers a signature suite. Bootstrap ships
-;; rsa-sha256-2018 and ed25519-2020; the suite name maps an
-;; algorithm to a :verify body and a :key-format predicate.
-
-(DefineObject
-  :name "DefineSigSuite"
-  :doc "Signature suite registration. :name identifies the suite\n        ('rsa-sha256-2018', 'ed25519-2020', ...); :verify is the\n        SX (canonical-bytes signature key) -> bool body; the\n        envelope-signature validator dispatches by suite name."
-  :schema (fn
-    (obj)
-    (and (string? (-> obj :name)) (not (nil? (-> obj :verify))))))

next/genesis/object-types/define-validator.sx

@@ -1,12 +0,0 @@
-;; next/genesis/object-types/define-validator.sx
-;;
-;; Meta-object that registers a validator predicate. The validation
-;; pipeline (Step 6) consults registered validators by name when
-;; running its stages.
-
-(DefineObject
-  :name "DefineValidator"
-  :doc "Validator registration. :name is the validator key (e.g.\n        \"envelope-shape\"); :predicate is the SX (activity) ->\n        ok|{error, R} body."
-  :schema (fn
-    (obj)
-    (and (string? (-> obj :name)) (not (nil? (-> obj :predicate))))))

next/genesis/object-types/note.sx

@@ -1,10 +0,0 @@
-;; next/genesis/object-types/note.sx
-;;
-;; Short message intended for an audience, ActivityPub-Note-compatible.
-;; Used by the Step 9b reactive smoke test (Note tagged "smoketest"
-;; matches the Topic subscription).
-
-(DefineObject
-  :name "Note"
-  :doc "Short authored message. :content is the body text;\n        :tags is a list of subscription-routable tags."
-  :schema (fn (obj) (string? (-> obj :content))))

next/genesis/object-types/snapshot.sx

@@ -1,13 +0,0 @@
-;; next/genesis/object-types/snapshot.sx
-;;
-;; Projection state checkpoint. The projection scheduler emits
-;; Snapshot{projection-name, state-cid, log-seq} periodically;
-;; cold starts read the most recent Snapshot and replay only
-;; activities after :log-seq. Per design §10.5.
-
-(DefineObject
-  :name "Snapshot"
-  :doc "Projection-state checkpoint. :projection-name identifies\n        the projection; :state-cid is the content-address of\n        the snapshotted state value; :log-seq is the activity\n        sequence number the snapshot was taken at."
-  :schema (fn
-    (obj)
-    (and (string? (-> obj :projection-name)) (string? (-> obj :state-cid)))))

next/genesis/object-types/sx-artifact.sx

@@ -1,10 +0,0 @@
-;; next/genesis/object-types/sx-artifact.sx
-;;
-;; Content-addressed SX source — a library, component, or
-;; executable form published via Create{SXArtifact{...}}.
-;; Consumers reference an artifact by its CID. Per design §3.4.
-
-(DefineObject
-  :name "SXArtifact"
-  :doc "Published SX source. :source carries the form text;\n        :language is optional ('sx' by default); :imports lists\n        CIDs the artifact depends on."
-  :schema (fn (obj) (string? (-> obj :source))))

next/genesis/object-types/tombstone.sx

@@ -1,9 +0,0 @@
-;; next/genesis/object-types/tombstone.sx
-;;
-;; Replacement for an object that has been Delete'd. Lets projection
-;; folds keep a marker without retaining the deleted content.
-
-(DefineObject
-  :name "Tombstone"
-  :doc "Marker for a deleted object. :former-cid carries the CID\n        of the object that was removed. Projections fold Tombstone\n        by replacing the cached entry (not by omitting it)."
-  :schema (fn (obj) (string? (-> obj :former-cid))))

next/genesis/projections/activity-log.sx

@@ -1,11 +0,0 @@
-;; next/genesis/projections/activity-log.sx
-;;
-;; Identity projection: stores every activity by its CID. The
-;; base ledger every other projection could be re-derived from
-;; if needed. Per design §10.2.
-
-(DefineProjection
-  :name "activity-log"
-  :doc "Maps activity CID to the full envelope. Every activity\n        flows through; no filter. State is the CID-keyed dict."
-  :initial-state {}
-  :fold (fn (state act) (assoc state (-> act :cid) act)))

next/genesis/projections/actor-state.sx

@@ -1,26 +0,0 @@
-;; next/genesis/projections/actor-state.sx
-;;
-;; Per-actor live state: publicKeys (with history per design §9.6),
-;; profile fields (preferredUsername, summary, ...), follower/
-;; following counts. Powers the actor doc endpoint and the
-;; time-aware signature verification in envelope:verify_signature/2.
-
-(DefineProjection
-  :name "actor-state"
-  :doc "Actor-id -> {publicKeys, profile, followers, following}.\n        Updated by Create{Person|Service|Group}, Update (key\n        rotation, profile edits), Move (federation migration)."
-  :initial-state {}
-  :fold (fn
-    (state act)
-    (let
-      ((aid (-> act :actor)) (t (-> act :type)))
-      (cond
-        (= t "Create")
-        (assoc state aid (or (-> act :object) {}))
-        (= t "Update")
-        (assoc
-          state
-          aid
-          (merge
-            (or (get state aid) {})
-            (or (-> act :patch) {})))
-        :else state))))

next/genesis/projections/audience-graph.sx

@@ -1,25 +0,0 @@
-;; next/genesis/projections/audience-graph.sx
-;;
-;; Per-actor follow / follower graph and audience caches. Folded
-;; from Follow / Accept / Reject / Undo{Follow}. Used by the
-;; activity router to expand :to / :cc audiences (Public,
-;; Followers, Direct) into concrete recipient sets. Per design §16.
-
-(DefineProjection
-  :name "audience-graph"
-  :doc "Actor-id -> {following, followers, pending} sets.\n        Updated by Follow / Accept / Reject / Undo. Federation\n        (m2) wires this projection to the delivery queue."
-  :initial-state {}
-  :fold (fn
-    (state act)
-    (let
-      ((t (-> act :type)))
-      (cond
-        (= t "Follow")
-        state
-        (= t "Accept")
-        state
-        (= t "Reject")
-        state
-        (= t "Undo")
-        state
-        :else state))))

next/genesis/projections/by-actor.sx

@@ -1,15 +0,0 @@
-;; next/genesis/projections/by-actor.sx
-;;
-;; Index of activity CIDs grouped by :actor. Maps actor-id to a
-;; list of CIDs in append order. Powers the per-actor outbox
-;; listing (Step 8) without re-scanning the full log.
-
-(DefineProjection
-  :name "by-actor"
-  :doc "Actor-id -> list of activity CIDs (append order)."
-  :initial-state {}
-  :fold (fn
-    (state act)
-    (let
-      ((a (-> act :actor)) (cid (-> act :cid)))
-      (assoc state a (append (or (get state a) (list)) (list cid))))))

next/genesis/projections/by-object.sx

@@ -1,22 +0,0 @@
-;; next/genesis/projections/by-object.sx
-;;
-;; Index of activities that reference each :object CID. Maps
-;; object-CID to the list of activity CIDs that target it
-;; (Update / Delete / Announce / etc.). Used for "show me
-;; everything that happened to X" queries.
-
-(DefineProjection
-  :name "by-object"
-  :doc "Object CID -> list of activity CIDs that target it."
-  :initial-state {}
-  :fold (fn
-    (state act)
-    (let
-      ((obj-cid (-> act :object)) (cid (-> act :cid)))
-      (if
-        (string? obj-cid)
-        (assoc
-          state
-          obj-cid
-          (append (or (get state obj-cid) (list)) (list cid)))
-        state))))

next/genesis/projections/by-type.sx

@@ -1,15 +0,0 @@
-;; next/genesis/projections/by-type.sx
-;;
-;; Index of activity CIDs grouped by :type. Maps type-name to a
-;; list of CIDs in append order. Used by the outbox listing
-;; endpoints (Step 8) for type-filtered pagination.
-
-(DefineProjection
-  :name "by-type"
-  :doc "Type-name -> list of activity CIDs (append order)."
-  :initial-state {}
-  :fold (fn
-    (state act)
-    (let
-      ((t (-> act :type)) (cid (-> act :cid)))
-      (assoc state t (append (or (get state t) (list)) (list cid))))))

next/genesis/projections/define-registry.sx

@@ -1,33 +0,0 @@
-;; next/genesis/projections/define-registry.sx
-;;
-;; The meta-projection: folds Create{Define*{...}} activities into
-;; the kernel registry. Resolves the chicken-and-egg circle —
-;; bootstrap.erl populates the registry directly at startup from
-;; the genesis bundle, and from then on define-registry's fold
-;; keeps it current as new Define* activities arrive. Per design §5.
-
-(DefineProjection
-  :name "define-registry"
-  :doc "Maps {kind, name} -> definition entry. Folded from\n        Create{DefineActivity|DefineObject|DefineProjection|\n        DefineValidator|DefineCodec|DefineSigSuite|...}. Kind is\n        derived from the inner :object :type tag."
-  :initial-state {}
-  :fold (fn
-    (state act)
-    (let
-      ((obj (-> act :object)) (otype (-> act :object :type)))
-      (cond
-        (= (-> act :type) "Create")
-        (cond
-          (= otype "DefineActivity")
-          (assoc-in state (list :activity-types (-> obj :name)) obj)
-          (= otype "DefineObject")
-          (assoc-in state (list :object-types (-> obj :name)) obj)
-          (= otype "DefineProjection")
-          (assoc-in state (list :projections (-> obj :name)) obj)
-          (= otype "DefineValidator")
-          (assoc-in state (list :validators (-> obj :name)) obj)
-          (= otype "DefineCodec")
-          (assoc-in state (list :codecs (-> obj :name)) obj)
-          (= otype "DefineSigSuite")
-          (assoc-in state (list :sig-suites (-> obj :name)) obj)
-          :else state)
-        :else state))))

next/genesis/sig-suites/ed25519-2020.sx

@@ -1,11 +0,0 @@
-;; next/genesis/sig-suites/ed25519-2020.sx
-;;
-;; W3C Verifiable Credential signature suite — Ed25519 over
-;; canonical bytes, key material in multibase. Default suite
-;; for fed-sx actors per design §9.
-
-(DefineSigSuite
-  :name "ed25519-2020"
-  :doc "Ed25519 verification. Key carries publicKeyMultibase.\n        :verify takes canonical-bytes + signature + key and\n        returns bool. Real verification deferred to m2 once\n        crypto:verify_ed25519/3 BIF lands; v1 stand-in returns\n        false to defer all Ed25519-signed activities."
-  :verify (fn (canonical-bytes signature key) false)
-  :key-format (fn (key-doc) (string? (-> key-doc :publicKeyMultibase))))

next/genesis/sig-suites/rsa-sha256-2018.sx

@@ -1,11 +0,0 @@
-;; next/genesis/sig-suites/rsa-sha256-2018.sx
-;;
-;; W3C Verifiable Credential signature suite — RSA-SHA256 over
-;; canonical bytes, key material in PEM. Compatible with
-;; Mastodon's HTTP-Signatures / Linked-Data-Signatures-2017.
-
-(DefineSigSuite
-  :name "rsa-sha256-2018"
-  :doc "RSA-SHA256 verification. Key carries publicKeyPem.\n        :verify takes canonical-bytes + signature + key and\n        returns bool. Real verification deferred to m2 once\n        crypto:verify_rsa/3 BIF lands; v1 stand-in returns\n        false to defer all RSA-signed activities."
-  :verify (fn (canonical-bytes signature key) false)
-  :key-format (fn (key-doc) (string? (-> key-doc :publicKeyPem))))

next/genesis/validators/envelope-shape.sx

@@ -1,22 +0,0 @@
-;; next/genesis/validators/envelope-shape.sx
-;;
-;; Validates required envelope fields per design §3.1. Stage 1 of
-;; the validation pipeline (Step 6). Mirrors the kernel's
-;; envelope:validate_shape/1 from Step 2a — when the pipeline runs
-;; in OCaml-side sandbox eval mode it dispatches by name; when it
-;; runs through the kernel Erlang path it short-circuits to the BIF.
-
-(DefineValidator
-  :name "envelope-shape"
-  :doc "Required-fields check on the activity envelope:\n        :id, :type, :actor, :published, :signature must all be\n        present and non-nil. The :signature sub-field needs\n        :key_id, :algorithm, :value."
-  :predicate (fn
-    (act)
-    (and
-      (not (nil? (-> act :id)))
-      (not (nil? (-> act :type)))
-      (not (nil? (-> act :actor)))
-      (not (nil? (-> act :published)))
-      (not (nil? (-> act :signature)))
-      (not (nil? (-> act :signature :key_id)))
-      (not (nil? (-> act :signature :algorithm)))
-      (not (nil? (-> act :signature :value))))))

next/genesis/validators/signature.sx

@@ -1,13 +0,0 @@
-;; next/genesis/validators/signature.sx
-;;
-;; Stage 2 of the validation pipeline per design §14. Verifies the
-;; activity signature against the time-relevant public key in the
-;; actor-state projection. Bootstrap entry; the kernel dispatches
-;; to envelope:verify_signature/2 (Step 2c) when running in
-;; Erlang-on-SX mode. Per design §9.6 the lookup is timestamp-aware
-;; — key validity is evaluated at :published, not "now".
-
-(DefineValidator
-  :name "signature"
-  :doc "Signature verification. Picks the signature suite by\n        :signature :algorithm, fetches the key with id ==\n        :signature :key_id that was active at :published from\n        the actor-state projection, then dispatches to the\n        suite's :verify body."
-  :predicate (fn (act) true))

next/genesis/validators/type-schema.sx

@@ -1,21 +0,0 @@
-;; next/genesis/validators/type-schema.sx
-;;
-;; Stage 5 of the validation pipeline per design §14. Validates
-;; the activity's :object against the schema registered for its
-;; :object :type in the define-registry projection.
-
-(DefineValidator
-  :name "type-schema"
-  :doc "Looks up the object-type registration in the\n        define-registry projection, fetches its :schema body,\n        and evaluates it against (-> act :object). Returns true\n        when no object-type is named (some verbs carry no\n        :object) or when no schema is registered for the named\n        type (open-world default — Step 6 may tighten)."
-  :predicate (fn
-    (act)
-    (let
-      ((obj (-> act :object)))
-      (cond
-        (nil? obj)
-        true
-        (nil? (-> obj :type))
-        true
-        :else (let
-          ((schema (-> (registry-lookup :object-types (-> obj :type)) :schema)))
-          (if (nil? schema) true (apply-schema schema obj)))))))

next/kernel/bootstrap.erl

@@ -1,223 +0,0 @@
--module(bootstrap).
--export([read_genesis/0, read_genesis/1,
-         read_section/2, sections/0, section_subdir/1,
-         default_base/0, ends_with_sx/1,
-         build_genesis/1, verify_genesis/2,
-         cidhash_path/1, write_cidhash/2, read_cidhash/1,
-         load_genesis/1, strip_sx_suffix/1,
-         populate_registry/0,
-         start/3]).
-
-%% Genesis bundle reader per design §12.2.
-%%
-%% read_genesis/0,1 walks the seven canonical section subdirectories
-%% under `next/genesis/`, filters .sx files, reads each file into a
-%% binary, and returns a structured snapshot:
-%%
-%%   {ok, [{Section :: atom,
-%%          [{FileName :: binary, FileBytes :: binary}, ...]},
-%%         ...]}
-%%
-%% Step 4d will compute the bundle CID by hashing the assembled
-%% byte string across all entries; Step 4e will register the parsed
-%% definitions in the kernel registry.
-%%
-%% Port note: this module does NOT parse the .sx contents. The
-%% Erlang-on-SX port has no in-Erlang path from binary bytes to SX
-%% structured terms (same substrate gap that parked Step 3b); the
-%% bundle CID needs only the raw bytes, and registry registration
-%% will happen via an SX-side helper that the kernel hands the
-%% binary contents to. read_genesis/1 ignores its arg in v1 except
-%% to swap the BasePath — `default_base/0` is "next/genesis".
-%%
-%% Port note 2: string-literal binary segments `<<"abc">>` truncate
-%% to one byte in this port, so all path constants are hand-spelled
-%% as integer-segment binaries.
-
-%% ── Public API ──────────────────────────────────────────────────
-
-%% "next/genesis"
-default_base() ->
-    <<110,101,120,116,47,103,101,110,101,115,105,115>>.
-
-read_genesis() ->
-    read_genesis(default_base()).
-
-read_genesis(BasePath) ->
-    {ok, lists:map(
-           fun (S) -> {S, read_section(BasePath, S)} end,
-           sections())}.
-
-sections() ->
-    [activity_types, object_types, projections,
-     validators, codecs, sig_suites, audience].
-
-%% "activity-types"
-section_subdir(activity_types) ->
-    <<97,99,116,105,118,105,116,121,45,116,121,112,101,115>>;
-%% "object-types"
-section_subdir(object_types) ->
-    <<111,98,106,101,99,116,45,116,121,112,101,115>>;
-%% "projections"
-section_subdir(projections) ->
-    <<112,114,111,106,101,99,116,105,111,110,115>>;
-%% "validators"
-section_subdir(validators) ->
-    <<118,97,108,105,100,97,116,111,114,115>>;
-%% "codecs"
-section_subdir(codecs) ->
-    <<99,111,100,101,99,115>>;
-%% "sig-suites"
-section_subdir(sig_suites) ->
-    <<115,105,103,45,115,117,105,116,101,115>>;
-%% "audience"
-section_subdir(audience) ->
-    <<97,117,100,105,101,110,99,101>>.
-
-read_section(BasePath, Section) ->
-    SubDir = section_subdir(Section),
-    %% 47 = '/'
-    Path = <<BasePath/binary, 47, SubDir/binary>>,
-    case file:list_dir(Path) of
-        {ok, Names} ->
-            SxNames = lists:filter(fun (N) -> ends_with_sx(N) end, Names),
-            lists:map(fun (Name) -> read_one(Path, Name) end, SxNames);
-        {error, _} ->
-            []
-    end.
-
-%% Suffix check on the .sx extension. 46='.' 115='s' 120='x'.
-ends_with_sx(<<46, 115, 120>>) -> true;
-ends_with_sx(<<>>) -> false;
-ends_with_sx(<<_, Rest/binary>>) -> ends_with_sx(Rest).
-
-%% ── Internal ────────────────────────────────────────────────────
-
-read_one(DirPath, Name) ->
-    Full = <<DirPath/binary, 47, Name/binary>>,
-    case file:read_file(Full) of
-        {ok, Bytes} -> {Name, Bytes};
-        {error, R}  -> {Name, {error, R}}
-    end.
-
-%% ── Step 4d: bundle CID compute + verify ────────────────────────
-%%
-%% The bundle CID is the canonical content-address of everything in
-%% read_genesis/0's result. We delegate to the host `cid:to_string/1`
-%% BIF (Step 1b substrate): it walks the term via `er-format-value`,
-%% feeds the deterministic textual form into `cid-from-sx`, returns
-%% a CIDv1 (raw codec, sha2-256 multihash) as a binary.
-%%
-%% Design §12.3: at startup the kernel computes this CID and
-%% compares against a hardcoded value (here: a sibling `.cidhash`
-%% file). A mismatch is a hard refuse-to-start.
-
-build_genesis(ReadResult) ->
-    case ReadResult of
-        {ok, Sections} ->
-            Cid = cid:to_string({genesis_bundle, Sections}),
-            {ok, [{cid, Cid}, {sections, Sections}]};
-        Other ->
-            {error, {bad_read_result, Other}}
-    end.
-
-verify_genesis(ReadResult, ExpectedCid) ->
-    case build_genesis(ReadResult) of
-        {ok, [{cid, Cid}, _]} ->
-            case Cid =:= ExpectedCid of
-                true  -> ok;
-                false -> {error, {cid_mismatch, Cid, ExpectedCid}}
-            end;
-        Err -> Err
-    end.
-
-%% Sibling-file CID storage. "/.cidhash" appended to BasePath as
-%% an integer-segment binary (string-literal segments are broken).
-
-%% "/.cidhash" — 47='/' 46='.' c i d h a s h
-cidhash_path(BasePath) ->
-    <<BasePath/binary, 47, 46, 99, 105, 100, 104, 97, 115, 104>>.
-
-write_cidhash(BasePath, Cid) ->
-    file:write_file(cidhash_path(BasePath), Cid).
-
-read_cidhash(BasePath) ->
-    file:read_file(cidhash_path(BasePath)).
-
-%% ── Step 4e: load_genesis → registry ────────────────────────────
-%%
-%% Walks the read_genesis result and registers each file as a
-%% registry entry. The section atom is the registry kind directly
-%% (both name spaces are identical — see Step 4c sections/0 and
-%% Step 5a registry:kinds/0). The entry Name is the filename minus
-%% the `.sx` suffix, kept as a binary; the entry value is the
-%% file's raw bytes.
-%%
-%% Returns `{ok, RegistryState}` on success. Later steps (4f / the
-%% SX-parser bridge) will replace the raw bytes with parsed forms;
-%% the binary stand-in is enough to prove the bridge works.
-
-load_genesis(ReadResult) ->
-    case ReadResult of
-        {ok, Sections} ->
-            {ok, load_sections(Sections, registry:new())};
-        Other ->
-            {error, {bad_read_result, Other}}
-    end.
-
-load_sections([], State) -> State;
-load_sections([{Kind, Entries} | Rest], State) ->
-    load_sections(Rest, load_entries(Kind, Entries, State)).
-
-load_entries(_Kind, [], State) -> State;
-load_entries(Kind, [{Name, Bytes} | Rest], State) ->
-    BaseName = strip_sx_suffix(Name),
-    {ok, NewState} = registry:register(Kind, BaseName, Bytes, State),
-    load_entries(Kind, Rest, NewState).
-
-%% strip_sx_suffix(Binary) — drops the trailing ".sx" if present.
-%% 46='.' 115='s' 120='x'.
-strip_sx_suffix(B) when is_binary(B) ->
-    case ends_with_sx(B) of
-        false -> B;
-        true  -> take_prefix(B, byte_size(B) - 3)
-    end.
-
-take_prefix(_, 0) -> <<>>;
-take_prefix(<<H, Rest/binary>>, N) when N > 0 ->
-    Tail = take_prefix(Rest, N - 1),
-    <<H, Tail/binary>>.
-
-%% populate_registry/0 — load the canonical genesis bundle and
-%% register every entry in the running registry gen_server. The
-%% caller is expected to have started the registry (via
-%% registry:start_link/0) before calling this. Returns the count
-%% of entries registered across all kinds.
-populate_registry() ->
-    {ok, Sections} = read_genesis(),
-    populate_sections(Sections, 0).
-
-populate_sections([], Count) -> Count;
-populate_sections([{Kind, Entries} | Rest], Count) ->
-    populate_sections(Rest, Count + populate_entries(Kind, Entries, 0)).
-
-populate_entries(_, [], Count) -> Count;
-populate_entries(Kind, [{Name, Bytes} | Rest], Count) ->
-    BaseName = strip_sx_suffix(Name),
-    ok = registry:register(Kind, BaseName, Bytes),
-    populate_entries(Kind, Rest, Count + 1).
-
-%% start/3 — one-call bring-up of the kernel substrate. Starts
-%% the registry gen_server, populates it from the canonical
-%% genesis bundle, then starts the nx_kernel gen_server with the
-%% supplied actor identity / key / state. Returns the nx_kernel
-%% Pid (gen_server start_link convention in this port returns the
-%% raw Pid, not {ok, Pid}).
-%%
-%% Tests + production bring-up share this entry point. The
-%% caller is still responsible for starting any application-level
-%% projections and wiring them via nx_kernel:with_projections/1.
-start(ActorId, KeySpec, ActorState) ->
-    registry:start_link(),
-    populate_registry(),
-    nx_kernel:start_link(ActorId, KeySpec, ActorState).

next/kernel/define_registry.erl

@@ -1,68 +0,0 @@
--module(define_registry).
--export([fold/2, fold_fn/0, define_kind/1]).
-
-%% Define-registry projection fold — Erlang-fun stand-in for the
-%% genesis `define-registry.sx` body. The intent is identical: a
-%% projection whose state is a registry-shaped property list, fed
-%% by every `Create{Define*{...}}` activity. The SX body would
-%% eventually replace this once an SX-source eval bridge lets the
-%% kernel evaluate the genesis fold directly; until then this
-%% Erlang module proves the meta-projection mechanism wires
-%% through `projection:fold_fn` and `nx_kernel` cleanly.
-%%
-%% State shape mirrors `registry:new()` exactly:
-%%   [{Kind, [{Name, Entry}, ...]}, ...]
-%% so callers can use `registry:lookup/3` etc. on the result.
-%%
-%% Type discrimination uses atoms (`define_activity`, …). Real SX
-%% would carry the string forms ("DefineActivity", …); the bridge
-%% will translate. See define_kind/1 for the mapping.
-
-fold(Activity, State) ->
-    case envelope:get_field(type, Activity) of
-        {ok, create} -> fold_create(Activity, State);
-        _ -> State
-    end.
-
-fold_create(Activity, State) ->
-    case envelope:get_field(object, Activity) of
-        {ok, Obj} ->
-            case envelope:get_field(type, Obj) of
-                {ok, ObjType} ->
-                    case define_kind(ObjType) of
-                        not_a_define -> State;
-                        Kind -> fold_register(Kind, Obj, State)
-                    end;
-                _ -> State
-            end;
-        _ -> State
-    end.
-
-fold_register(Kind, Obj, State) ->
-    case envelope:get_field(name, Obj) of
-        {ok, Name} ->
-            case registry:register(Kind, Name, Obj, State) of
-                {ok, NewState}     -> NewState;
-                {error, unknown_kind} -> State
-            end;
-        not_found -> State
-    end.
-
-%% fold_fn/0 — a 2-arity Erlang fun the projection module plants
-%% in its record's :fold slot. Lets `projection:start_link/3`
-%% wire define-registry directly.
-fold_fn() ->
-    fun (Activity, State) -> fold(Activity, State) end.
-
-%% define_kind/1 — discriminator from the inner Define* object's
-%% :type atom to the registry kind atom. Anything unrecognised
-%% returns not_a_define so the fold treats it as a pass-through.
-
-define_kind(define_activity)   -> activity_types;
-define_kind(define_object)     -> object_types;
-define_kind(define_projection) -> projections;
-define_kind(define_validator)  -> validators;
-define_kind(define_codec)      -> codecs;
-define_kind(define_sig_suite)  -> sig_suites;
-define_kind(define_audience)   -> audience;
-define_kind(_)                 -> not_a_define.

next/kernel/envelope.erl

@@ -1,177 +0,0 @@
--module(envelope).
--export([validate_shape/1, get_field/2, canonical_bytes/1, verify_signature/2]).
-
-%% Activity envelope per design §3.1.
-%%
-%% Erlang maps (#{...}) are not supported by this port, so envelopes
-%% are represented as property lists of {atom_key, value} pairs. This
-%% port's binary syntax also can't carry string literals; values that
-%% would naturally be binaries in real Erlang are kept as atoms or
-%% integer-segment binaries in the test corpus.
-%%
-%% Required fields: id, type, actor, published, signature.
-%% The signature value is itself a property list with key_id,
-%% algorithm, value.
-%%
-%% validate_shape/1 returns ok | {error, Reason}. Reasons:
-%%   not_a_proplist
-%%   {missing_field, FieldName}
-%%   {bad_signature, BadSigReason}
-%%
-%% get_field/2 returns {ok, Value} | not_found.
-
-validate_shape(Env) when is_list(Env) ->
-    case check_required([id, type, actor, published, signature], Env) of
-        ok -> validate_signature_shape(Env);
-        Err -> Err
-    end;
-validate_shape(_) ->
-    {error, not_a_proplist}.
-
-get_field(_, []) -> not_found;
-get_field(K, [{K, V} | _]) -> {ok, V};
-get_field(K, [_ | Rest]) -> get_field(K, Rest).
-
-check_required([], _) -> ok;
-check_required([F | Rest], Env) ->
-    case get_field(F, Env) of
-        {ok, _} -> check_required(Rest, Env);
-        not_found -> {error, {missing_field, F}}
-    end.
-
-validate_signature_shape(Env) ->
-    {ok, Sig} = get_field(signature, Env),
-    case is_list(Sig) of
-        true ->
-            case check_required([key_id, algorithm, value], Sig) of
-                ok -> ok;
-                {error, {missing_field, F}} ->
-                    {error, {bad_signature, {missing_field, F}}}
-            end;
-        false ->
-            {error, {bad_signature, not_a_proplist}}
-    end.
-
-%% canonical_bytes/1 — the byte string the signature covers.
-%%
-%% Real fed-sx will use dag-cbor over a JSON-LD-canonicalised form
-%% (design §3.2). For milestone 1 we stand in for that with the host
-%% BIF `cid:to_string/1`, which produces a CIDv1 over the deterministic
-%% textual form of the term. Two prior steps make this work:
-%%   1. The signature pair is stripped (sig covers everything except
-%%      itself).
-%%   2. The top-level property list is sorted by key so field order in
-%%      the source envelope is not load-bearing.
-%%
-%% The result is an Erlang binary suitable as the sig-cover input.
-
-canonical_bytes(Env) when is_list(Env) ->
-    Stripped = strip_signature(Env),
-    Sorted = sort_pairs(Stripped),
-    cid:to_string(Sorted).
-
-strip_signature([]) -> [];
-strip_signature([{signature, _} | Rest]) -> strip_signature(Rest);
-strip_signature([P | Rest]) -> [P | strip_signature(Rest)].
-
-sort_pairs([]) -> [];
-sort_pairs([H | T]) -> insert_pair(H, sort_pairs(T)).
-
-insert_pair(P, []) -> [P];
-insert_pair({K1, V1}, [{K2, V2} | Rest]) ->
-    case K1 < K2 of
-        true  -> [{K1, V1}, {K2, V2} | Rest];
-        false -> [{K2, V2} | insert_pair({K1, V1}, Rest)]
-    end.
-
-%% verify_signature/2 — time-aware sig verification per design §9.6.
-%%
-%% Activity carries a `signature` proplist with `key_id`, `algorithm`,
-%% `value`. ActorState carries `public_keys` — a list of key proplists
-%% with `id`, `created`, optionally `superseded_at`, and `value` (the
-%% key material).
-%%
-%% A key is active at time T iff `created =< T` AND
-%% (no `superseded_at` OR T < `superseded_at`). Verification picks the
-%% first matching active key whose `id == signature.key_id` at the
-%% activity's `published` timestamp, then recomputes the MAC
-%% `crypto:hash(sha256, <<KeyMaterial/binary, CanonicalBytes/binary>>)`
-%% and compares it to `signature.value`.
-%%
-%% Returns ok | {error, Reason}. Reasons:
-%%   no_signature | no_key_id | no_published | no_keys |
-%%   no_active_key | bad_signature
-%%
-%% Real RSA-SHA256 / Ed25519 verification is deferred to milestone 2:
-%% Phase 8 only ships `crypto:hash/2`, so we stand in with an HMAC-shaped
-%% MAC that exercises the same key-lookup and canonical-bytes pipeline.
-
-verify_signature(Activity, ActorState) ->
-    case get_field(signature, Activity) of
-        not_found -> {error, no_signature};
-        {ok, Sig} ->
-            case get_field(key_id, Sig) of
-                not_found -> {error, no_key_id};
-                {ok, KeyId} ->
-                    case get_field(published, Activity) of
-                        not_found -> {error, no_published};
-                        {ok, Published} ->
-                            verify_with_keys(Activity, Sig, KeyId,
-                                             Published, ActorState)
-                    end
-            end
-    end.
-
-verify_with_keys(Activity, Sig, KeyId, Published, ActorState) ->
-    case get_field(public_keys, ActorState) of
-        not_found -> {error, no_keys};
-        {ok, Keys} ->
-            case find_active_key(KeyId, Published, Keys) of
-                not_found -> {error, no_active_key};
-                {ok, Key} -> verify_mac(Activity, Sig, Key)
-            end
-    end.
-
-find_active_key(_, _, []) -> not_found;
-find_active_key(KeyId, Now, [Key | Rest]) ->
-    case is_matching_active_key(Key, KeyId, Now) of
-        true -> {ok, Key};
-        false -> find_active_key(KeyId, Now, Rest)
-    end.
-
-is_matching_active_key(Key, WantId, Now) ->
-    case get_field(id, Key) of
-        {ok, WantId} -> is_active_at(Key, Now);
-        _ -> false
-    end.
-
-is_active_at(Key, Now) ->
-    case get_field(created, Key) of
-        not_found -> false;
-        {ok, Created} ->
-            case Now >= Created of
-                false -> false;
-                true ->
-                    case get_field(superseded_at, Key) of
-                        not_found -> true;
-                        {ok, SupAt} -> Now < SupAt
-                    end
-            end
-    end.
-
-verify_mac(Activity, Sig, Key) ->
-    case get_field(value, Sig) of
-        not_found -> {error, bad_signature};
-        {ok, SigValue} ->
-            case get_field(value, Key) of
-                not_found -> {error, bad_signature};
-                {ok, KeyMat} ->
-                    Bytes = canonical_bytes(Activity),
-                    Computed = crypto:hash(sha256,
-                        <<KeyMat/binary, Bytes/binary>>),
-                    case SigValue =:= Computed of
-                        true -> ok;
-                        false -> {error, bad_signature}
-                    end
-            end
-    end.

next/kernel/http_server.erl

@@ -1,604 +0,0 @@
--module(http_server).
--export([start/1, start/2]).
--export([route/1, route/2, ok_response/1, not_found_response/0,
-         welcome_body/0, capabilities_body/0,
-         capabilities_path/0,
-         match_prefix/2, actors_prefix/0, actor_doc_response/1,
-         artifacts_prefix/0, artifact_response/1,
-         projections_list_path/0, projections_prefix/0,
-         projections_list_response/0, projection_response/1,
-         activity_path/0, unauthorized_response/0,
-         post_activity_response/0,
-         validation_failed_response/0,
-         cid_response/1,
-         accept_format/1, accept_format_from/1,
-         capabilities_body_for/1,
-         content_type_for/1, ok_response/2,
-         cid_response_for/2, post_activity_response_for/1,
-         actor_doc_response_for/2, artifact_response_for/2,
-         projection_response_for/2, projections_list_response_for/1]).
-
-%% HTTP request router per design §16.1.
-%%
-%% Request shape (mirrors what the SX-side `http-listen` builds and
-%% the http:listen/2 BIF bridge marshals into a proplist):
-%%   [{method, Binary}, {path, Binary}, {query, Binary},
-%%    {headers, [{Name, Value}, ...]}, {body, Binary}]
-%%
-%% Response shape:
-%%   [{status, Integer}, {headers, [{Name, Value}, ...]}, {body, Binary}]
-%%
-%% Real dispatch (actor docs, outbox listings, /activity POST,
-%% /.well-known/sx-capabilities, etc.) lands in Step 8c+. Step 8b
-%% wires the route/1 shape and a single hello-world handler that
-%% proves the request→response round-trip.
-%%
-%% Method/path comparison uses integer-segment binaries because
-%% `<<"GET">>` truncates to a single byte in this port.
-
-%% Step 8b-start. `http:listen/2` blocks the calling process
-%% forever (it's a native accept-loop on a TCP socket), so callers
-%% wrap it in a spawned Erlang process. `start/1` is the bare form;
-%% `start/2` accepts the same Cfg proplist that `route/2` uses so
-%% the spawned handler closes over `:publish_token`, etc.
-%%
-%% Returns the Pid of the listener process; the caller can `link`
-%% it or `monitor` it as needed. The handler always returns a
-%% response — uncaught Erlang errors become a generic 500 via the
-%% native primitive's try/with-fallback in sx_server.ml.
-
-start(Port) ->
-    start(Port, []).
-
-start(Port, Cfg) ->
-    spawn(fun () -> http:listen(Port, fun (Req) -> route(Req, Cfg) end) end).
-
-route(Req) ->
-    route(Req, []).
-
-%% route/2 — Cfg proplist carries optional `:publish_token` (binary)
-%% for POST /activity auth. Other state (logs, projections, etc.) is
-%% not yet threaded through — POST /activity returns a stub 200
-%% once auth succeeds; real outbox:publish glue lands separately.
-route(Req, Cfg) ->
-    M = field(method, Req),
-    P = field(path, Req),
-    F = accept_format_from(Req),
-    case {M, P} of
-        {<<80,79,83,84>>, <<47,97,99,116,105,118,105,116,121>>} ->
-            handle_post_activity(Req, Cfg);
-        {<<71,69,84>>,
-         <<47,46,119,101,108,108,45,107,110,111,119,110,
-           47,115,120,45,99,97,112,97,98,105,108,105,116,105,101,115>>} ->
-            ok_response(capabilities_body_for(F));
-        _ ->
-            dispatch(M, P, F)
-    end.
-
-%% Backward-compat /2 wrapper — defaults to text format. Route
-%% computes Format from the Accept header and calls dispatch/3
-%% directly; dispatch/2 is kept for callers that don't have a
-%% format in scope.
-dispatch(M, P) ->
-    dispatch(M, P, text).
-
-%% 71 69 84 = "GET"  | 47 = "/"
-dispatch(<<71, 69, 84>>, <<47>>, _F) ->
-    ok_response(welcome_body());
-%% GET /.well-known/sx-capabilities — Format threaded through
-dispatch(<<71, 69, 84>>,
-         <<47,46,119,101,108,108,45,107,110,111,119,110,
-           47,115,120,45,99,97,112,97,98,105,108,105,116,105,101,115>>, F) ->
-    ok_response(capabilities_body_for(F));
-%% GET /projections — list stub. Comes before the /projections/{name}
-%% prefix clause because the bare path has no trailing slash.
-dispatch(<<71, 69, 84>>, <<47,112,114,111,106,101,99,116,105,111,110,115>>, F) ->
-    projections_list_response_for(F);
-%% GET /actors/{id} or /artifacts/{cid} or /projections/{name}
-dispatch(<<71, 69, 84>>, Path, F) ->
-    case match_prefix(actors_prefix(), Path) of
-        {ok, Id} when byte_size(Id) > 0 ->
-            actor_doc_response_for(Id, F);
-        _ ->
-            case match_prefix(artifacts_prefix(), Path) of
-                {ok, Cid} when byte_size(Cid) > 0 ->
-                    artifact_response_for(Cid, F);
-                _ ->
-                    case match_prefix(projections_prefix(), Path) of
-                        {ok, Name} when byte_size(Name) > 0 ->
-                            projection_response_for(Name, F);
-                        _ ->
-                            not_found_response()
-                    end
-            end
-    end;
-dispatch(_, _, _) ->
-    not_found_response().
-
-%% "fed-sx kernel m1\n" — 17 bytes, hand-spelled.
-%%  f  e  d  -  s  x   _   k   e   r   n   e   l   _   m   1   \n
-welcome_body() ->
-    <<102,101,100,45,115,120,32,107,101,114,110,101,108,32,109,49,10>>.
-
-%% "/.well-known/sx-capabilities" — exposed for callers that build
-%% requests in tests or that need the canonical path string.
-capabilities_path() ->
-    <<47,46,119,101,108,108,45,107,110,111,119,110,
-      47,115,120,45,99,97,112,97,98,105,108,105,116,105,101,115>>.
-
-%% Capability descriptor body. Returned as plain text per design
-%% §16; future content-negotiation work (Step 8d) layers JSON /
-%% dag-cbor / SX representations on top.
-%%
-%% Lines (each terminated by \n = 10):
-%%   "kernel: fed-sx-m1\n"
-%%   "version: 0.0.1\n"
-%%   "verbs: Create Update Delete\n"
-capabilities_body() ->
-    <<107,101,114,110,101,108,58,32,102,101,100,45,115,120,45,109,49,10,
-      118,101,114,115,105,111,110,58,32,48,46,48,46,49,10,
-      118,101,114,98,115,58,32,67,114,101,97,116,101,32,85,112,100,97,116,101,32,68,101,108,101,116,101,10>>.
-
-ok_response(Body) ->
-    [{status, 200}, {headers, []}, {body, Body}].
-
-not_found_response() ->
-    [{status, 404}, {headers, []},
-     {body, <<110,111,116,32,102,111,117,110,100,10>>}].  % "not found\n"
-
-%% Internal property-list field lookup. Returns nil when missing
-%% so the route falls into the not_found arm gracefully.
-field(K, [{K, V} | _]) -> V;
-field(K, [_ | Rest]) -> field(K, Rest);
-field(_, []) -> nil.
-
-%% ── Dynamic-segment routing ─────────────────────────────────────
-%%
-%% match_prefix(Prefix, Path) — if Path starts with the entire
-%% Prefix binary, return {ok, Rest} where Rest is the remaining
-%% bytes; else return nomatch. Pure byte-level pattern match,
-%% no regex / no parsing. Path-segment splitting comes in later
-%% sub-deliverables (8c-art, 8c-proj) where it's needed.
-
-match_prefix(<<>>, Rest) -> {ok, Rest};
-match_prefix(<<B, PRest/binary>>, <<B, PathRest/binary>>) ->
-    match_prefix(PRest, PathRest);
-match_prefix(_, _) -> nomatch.
-
-%% "/actors/" — 8 bytes: 47 97 99 116 111 114 115 47
-actors_prefix() ->
-    <<47,97,99,116,111,114,115,47>>.
-
-%% Actor doc stub. Real implementation (Step 8c continuation) will
-%% fetch the actor-state projection entry and serialise it; v1
-%% returns the id as the body so route resolution can be exercised
-%% end-to-end without the projection wiring.
-actor_doc_response(Id) ->
-    %% "actor: " — 7 bytes
-    Pre = <<97,99,116,111,114,58,32>>,
-    Body = <<Pre/binary, Id/binary, 10>>,
-    ok_response(Body).
-
-%% "/artifacts/" — 11 bytes
-artifacts_prefix() ->
-    <<47,97,114,116,105,102,97,99,116,115,47>>.
-
-%% Artifact stub. Real implementation will fetch the bytes from
-%% the registry (or a CID-keyed store) and content-negotiate.
-%% v1 echoes the CID so route resolution can be tested.
-artifact_response(Cid) ->
-    %% "artifact: " — 10 bytes
-    Pre = <<97,114,116,105,102,97,99,116,58,32>>,
-    Body = <<Pre/binary, Cid/binary, 10>>,
-    ok_response(Body).
-
-%% "/projections" — 12 bytes (no trailing slash; the list endpoint)
-projections_list_path() ->
-    <<47,112,114,111,106,101,99,116,105,111,110,115>>.
-
-%% "/projections/" — 13 bytes (the per-projection prefix)
-projections_prefix() ->
-    <<47,112,114,111,106,101,99,116,105,111,110,115,47>>.
-
-%% Stub list response — real implementation queries the registry
-%% for active projections and serialises the name+CID list.
-projections_list_response() ->
-    %% "projections: (empty)\n" — hand-spelled
-    Body = <<112,114,111,106,101,99,116,105,111,110,115,58,32,
-             40,101,109,112,116,121,41,10>>,
-    ok_response(Body).
-
-projection_response(Name) ->
-    %% "projection: " — 12 bytes
-    Pre = <<112,114,111,106,101,99,116,105,111,110,58,32>>,
-    Body = <<Pre/binary, Name/binary, 10>>,
-    ok_response(Body).
-
-%% "/activity" — 9 bytes
-activity_path() ->
-    <<47,97,99,116,105,118,105,116,121>>.
-
-%% 401 Unauthorized response. Body: "unauthorized\n" = 13 bytes.
-unauthorized_response() ->
-    [{status, 401}, {headers, []},
-     {body, <<117,110,97,117,116,104,111,114,105,122,101,100,10>>}].
-
-%% Stub success body for POST /activity. Real impl will return
-%% the published activity's CID once outbox:publish is wired
-%% through a server-state context (Step 8c-post-publish).
-post_activity_response() ->
-    %% "published (stub)\n" — hand-spelled
-    Body = <<112,117,98,108,105,115,104,101,100,32,
-             40,115,116,117,98,41,10>>,
-    ok_response(Body).
-
-%% Auth helpers.
-
-handle_post_activity(Req, Cfg) ->
-    case check_bearer(Req, Cfg) of
-        ok ->
-            F = accept_format_from(Req),
-            publish_if_kernel(Req, F);
-        {error, _} ->
-            unauthorized_response()
-    end.
-
-%% publish_if_kernel/2 — if the nx_kernel gen_server is registered,
-%% delegate the publish there and translate the result. Otherwise
-%% keep the stub response so the auth-only tests stay green without
-%% having to spin up a kernel process. Format threads through to
-%% both stub and CID responses so the Content-Type matches what
-%% the client asked for via Accept.
-publish_if_kernel(Req, F) ->
-    case erlang:whereis(nx_kernel) of
-        undefined ->
-            post_activity_response_for(F);
-        _Pid ->
-            Body = field(body, Req),
-            Request = [{type, create}, {object, Body}],
-            case nx_kernel:publish(Request) of
-                {ok, Result} ->
-                    case envelope:get_field(cid, Result) of
-                        {ok, Cid} -> cid_response_for(Cid, F);
-                        _         -> post_activity_response_for(F)
-                    end;
-                {error, _} ->
-                    validation_failed_response()
-            end
-    end.
-
-%% 200 OK with body "cid: <cid>\n" (5 prefix bytes + cid + newline)
-cid_response(Cid) ->
-    %% "cid: " — 99 105 100 58 32
-    Pre = <<99,105,100,58,32>>,
-    Body = <<Pre/binary, Cid/binary, 10>>,
-    ok_response(Body).
-
-%% 422 Unprocessable Entity. Body "validation failed\n" — 18 bytes.
-validation_failed_response() ->
-    [{status, 422}, {headers, []},
-     {body, <<118,97,108,105,100,97,116,105,111,110,32,
-              102,97,105,108,101,100,10>>}].
-
-check_bearer(Req, Cfg) ->
-    case bearer_token(Req) of
-        {ok, Got} ->
-            case expected_token(Cfg) of
-                {ok, Want} when Got =:= Want -> ok;
-                _ -> {error, bad_token}
-            end;
-        not_found -> {error, no_auth}
-    end.
-
-%% Look up the Authorization header, strip "Bearer ", return token.
-bearer_token(Req) ->
-    case field(headers, Req) of
-        nil -> not_found;
-        Hs ->
-            %% "authorization" — 13 bytes, lowercase as the BIF wrapper
-            %% normalises headers to lowercase keys.
-            AuthKey = <<97,117,116,104,111,114,105,122,97,116,105,111,110>>,
-            case find_header(AuthKey, Hs) of
-                not_found -> not_found;
-                {ok, V} -> strip_bearer(V)
-            end
-    end.
-
-find_header(_, []) -> not_found;
-find_header(K, [{K, V} | _]) -> {ok, V};
-find_header(K, [_ | Rest]) -> find_header(K, Rest).
-
-%% "Bearer " — 7 bytes — strip and return the rest as the token.
-%% Anything else returns not_found (treated as missing auth).
-strip_bearer(V) ->
-    Prefix = <<66,101,97,114,101,114,32>>,
-    case match_prefix(Prefix, V) of
-        {ok, Token} when byte_size(Token) > 0 -> {ok, Token};
-        _ -> not_found
-    end.
-
-expected_token(Cfg) ->
-    case field(publish_token, Cfg) of
-        nil -> not_found;
-        T -> {ok, T}
-    end.
-
-%% ── Step 8d: Accept-header parsing ──────────────────────────────
-%%
-%% accept_format/1 — given an Accept header value, return the
-%% content-negotiation atom the route should serialise into. The
-%% first media-type prefix that matches wins, in this priority:
-%%   application/activity+json -> activity_json
-%%   application/json          -> json
-%%   application/sx            -> sx
-%%   application/cbor          -> cbor
-%% Anything else (including unrecognised, empty, or missing header)
-%% returns text — current routes default to text/plain bodies.
-%%
-%% Per-prefix recognition uses `match_prefix`. The header value is
-%% NOT split on `,` here; matching against the leading bytes is
-%% enough for the v1 envelope shapes the kernel currently emits.
-
-%% Media-type prefix byte sequences — hand-spelled because
-%% `<<"...">>` string-segments truncate in this port.
-
-%% "application/activity+json" — 25 bytes
-activity_json_prefix() ->
-    <<97,112,112,108,105,99,97,116,105,111,110,47,
-      97,99,116,105,118,105,116,121,43,106,115,111,110>>.
-
-%% "application/json" — 16 bytes
-json_prefix() ->
-    <<97,112,112,108,105,99,97,116,105,111,110,47,106,115,111,110>>.
-
-%% "application/sx" — 14 bytes
-sx_prefix() ->
-    <<97,112,112,108,105,99,97,116,105,111,110,47,115,120>>.
-
-%% "application/cbor" — 16 bytes
-cbor_prefix() ->
-    <<97,112,112,108,105,99,97,116,105,111,110,47,99,98,111,114>>.
-
-accept_format(nil) -> text;
-accept_format(<<>>) -> text;
-accept_format(V) when is_binary(V) ->
-    case match_prefix(activity_json_prefix(), V) of
-        {ok, _} -> activity_json;
-        _ ->
-            case match_prefix(json_prefix(), V) of
-                {ok, _} -> json;
-                _ ->
-                    case match_prefix(sx_prefix(), V) of
-                        {ok, _} -> sx;
-                        _ ->
-                            case match_prefix(cbor_prefix(), V) of
-                                {ok, _} -> cbor;
-                                _ -> text
-                            end
-                    end
-            end
-    end;
-accept_format(_) -> text.
-
-%% accept_format_from/1 — pull the Accept header out of a request
-%% proplist and run accept_format on its value. Lowercase key name
-%% (matches the BIF wrapper's normalisation).
-accept_format_from(Req) ->
-    case field(headers, Req) of
-        nil -> text;
-        Hs ->
-            %% "accept" — 6 bytes
-            K = <<97,99,99,101,112,116>>,
-            case find_header(K, Hs) of
-                {ok, V} -> accept_format(V);
-                not_found -> text
-            end
-    end.
-
-%% capabilities_body_for/1 — content-negotiated capability bodies.
-%% Each format returns a distinct byte sequence so dispatch can be
-%% observed end-to-end. Real serialisation (JSON-LD, dag-cbor, etc.)
-%% lands once the corresponding encoder BIFs are wired; v1 uses
-%% tagged stubs that are syntactically the right shape.
-capabilities_body_for(text) ->
-    capabilities_body();
-%% `{"caps":"fed-sx-m1"}\n` — 21 bytes
-capabilities_body_for(json) ->
-    <<123,34,99,97,112,115,34,58,34,
-      102,101,100,45,115,120,45,109,49,34,125,10>>;
-capabilities_body_for(activity_json) ->
-    %% Same payload as :json — the difference is the Content-Type
-    %% header (Step 8d-content-type follow-up); body shape matches.
-    capabilities_body_for(json);
-%% `(caps "fed-sx-m1")\n` — 19 bytes
-capabilities_body_for(sx) ->
-    <<40,99,97,112,115,32,34,
-      102,101,100,45,115,120,45,109,49,34,41,10>>;
-%% A minimal CBOR map: 0xA1 0x64 "caps" 0x69 "fed-sx-m1"
-%% A1 = map(1); 64 = text(4) "caps"; 69 = text(9) "fed-sx-m1"
-capabilities_body_for(cbor) ->
-    <<161,100,99,97,112,115,105,
-      102,101,100,45,115,120,45,109,49>>;
-capabilities_body_for(_) ->
-    capabilities_body().
-
-%% content_type_for/1 — MIME type binary for each format atom.
-%% "text/plain"                 — 10 bytes
-content_type_for(text) ->
-    <<116,101,120,116,47,112,108,97,105,110>>;
-%% "application/json"           — 16 bytes
-content_type_for(json) ->
-    <<97,112,112,108,105,99,97,116,105,111,110,47,
-      106,115,111,110>>;
-%% "application/activity+json"  — 25 bytes
-content_type_for(activity_json) ->
-    <<97,112,112,108,105,99,97,116,105,111,110,47,
-      97,99,116,105,118,105,116,121,43,106,115,111,110>>;
-%% "application/sx"             — 14 bytes
-content_type_for(sx) ->
-    <<97,112,112,108,105,99,97,116,105,111,110,47,
-      115,120>>;
-%% "application/cbor"           — 16 bytes
-content_type_for(cbor) ->
-    <<97,112,112,108,105,99,97,116,105,111,110,47,
-      99,98,111,114>>;
-content_type_for(_) ->
-    content_type_for(text).
-
-%% ok_response/2 — 200 OK with a Content-Type header derived from
-%% the Format atom. The header key is lowercase to match how the
-%% BIF wrapper normalises request headers.
-%% "content-type" — 12 bytes
-ok_response(Body, Format) ->
-    CTKey = <<99,111,110,116,101,110,116,45,116,121,112,101>>,
-    [{status, 200},
-     {headers, [{CTKey, content_type_for(Format)}]},
-     {body, Body}].
-
-%% cid_response_for/2 — format-aware version of cid_response/1.
-%% Each variant emits a syntactically appropriate body for the
-%% chosen format and tags the response with the matching
-%% Content-Type via ok_response/2.
-
-cid_response_for(Cid, text) ->
-    cid_response(Cid);
-%% `{"cid":"<cid>"}\n` — 8-byte prefix + cid + 3-byte suffix
-cid_response_for(Cid, json) ->
-    Pre = <<123,34,99,105,100,34,58,34>>,  % '{"cid":"'
-    Suf = <<34,125,10>>,                    % '"}\n'
-    ok_response(<<Pre/binary, Cid/binary, Suf/binary>>, json);
-cid_response_for(Cid, activity_json) ->
-    Pre = <<123,34,99,105,100,34,58,34>>,
-    Suf = <<34,125,10>>,
-    ok_response(<<Pre/binary, Cid/binary, Suf/binary>>, activity_json);
-%% `(cid "<cid>")\n` — 6-byte prefix + cid + 3-byte suffix
-cid_response_for(Cid, sx) ->
-    Pre = <<40,99,105,100,32,34>>,          % '(cid "'
-    Suf = <<34,41,10>>,                      % '")\n'
-    ok_response(<<Pre/binary, Cid/binary, Suf/binary>>, sx);
-%% v1 cbor stub: the raw CID bytes with the application/cbor CT.
-%% Real cbor encoding (A1 63 cid 78 <len> ...) lands later.
-cid_response_for(Cid, cbor) ->
-    ok_response(Cid, cbor);
-cid_response_for(Cid, _) ->
-    cid_response(Cid).
-
-%% post_activity_response_for/1 — format-aware version of
-%% post_activity_response/0 (the kernel-absent stub).
-
-post_activity_response_for(text) ->
-    post_activity_response();
-%% `{"status":"stub"}\n` — hand-spelled
-post_activity_response_for(json) ->
-    Body = <<123,34,115,116,97,116,117,115,34,58,34,
-             115,116,117,98,34,125,10>>,
-    ok_response(Body, json);
-post_activity_response_for(activity_json) ->
-    Body = <<123,34,115,116,97,116,117,115,34,58,34,
-             115,116,117,98,34,125,10>>,
-    ok_response(Body, activity_json);
-%% `(status "stub")\n`
-post_activity_response_for(sx) ->
-    Body = <<40,115,116,97,116,117,115,32,34,
-             115,116,117,98,34,41,10>>,
-    ok_response(Body, sx);
-post_activity_response_for(cbor) ->
-    %% Same body as text but with cbor CT — clients see the same
-    %% bytes as the text fallback. Step 8d-cbor encoder will replace.
-    [_, _, {body, Body}] = post_activity_response(),
-    ok_response(Body, cbor);
-post_activity_response_for(_) ->
-    post_activity_response().
-
-%% ── 8d-dispatch-get: format-aware GET responses ─────────────────
-%%
-%% Each builder mirrors its text-only counterpart but emits a
-%% format-tagged body and Content-Type. json/activity_json share
-%% the body shape but differ in CT; sx uses parenthesized form;
-%% cbor returns the raw payload bytes (encoder follow-up).
-
-%% actor_doc_response — text body `actor: <id>\n`.
-
-actor_doc_response_for(Id, text) ->
-    actor_doc_response(Id);
-actor_doc_response_for(Id, json) ->
-    Pre = <<123,34,97,99,116,111,114,34,58,34>>,  % '{"actor":"'
-    Suf = <<34,125,10>>,                           % '"}\n'
-    ok_response(<<Pre/binary, Id/binary, Suf/binary>>, json);
-actor_doc_response_for(Id, activity_json) ->
-    Pre = <<123,34,97,99,116,111,114,34,58,34>>,
-    Suf = <<34,125,10>>,
-    ok_response(<<Pre/binary, Id/binary, Suf/binary>>, activity_json);
-actor_doc_response_for(Id, sx) ->
-    Pre = <<40,97,99,116,111,114,32,34>>,          % '(actor "'
-    Suf = <<34,41,10>>,                             % '")\n'
-    ok_response(<<Pre/binary, Id/binary, Suf/binary>>, sx);
-actor_doc_response_for(Id, cbor) ->
-    ok_response(Id, cbor);
-actor_doc_response_for(Id, _) ->
-    actor_doc_response(Id).
-
-%% artifact_response — text body `artifact: <cid>\n`.
-
-artifact_response_for(Cid, text) ->
-    artifact_response(Cid);
-artifact_response_for(Cid, json) ->
-    Pre = <<123,34,97,114,116,105,102,97,99,116,34,58,34>>,
-    Suf = <<34,125,10>>,
-    ok_response(<<Pre/binary, Cid/binary, Suf/binary>>, json);
-artifact_response_for(Cid, activity_json) ->
-    Pre = <<123,34,97,114,116,105,102,97,99,116,34,58,34>>,
-    Suf = <<34,125,10>>,
-    ok_response(<<Pre/binary, Cid/binary, Suf/binary>>, activity_json);
-artifact_response_for(Cid, sx) ->
-    Pre = <<40,97,114,116,105,102,97,99,116,32,34>>,
-    Suf = <<34,41,10>>,
-    ok_response(<<Pre/binary, Cid/binary, Suf/binary>>, sx);
-artifact_response_for(Cid, cbor) ->
-    ok_response(Cid, cbor);
-artifact_response_for(Cid, _) ->
-    artifact_response(Cid).
-
-%% projection_response (singular) — text body `projection: <name>\n`.
-
-projection_response_for(Name, text) ->
-    projection_response(Name);
-projection_response_for(Name, json) ->
-    Pre = <<123,34,112,114,111,106,101,99,116,105,111,110,34,58,34>>,
-    Suf = <<34,125,10>>,
-    ok_response(<<Pre/binary, Name/binary, Suf/binary>>, json);
-projection_response_for(Name, activity_json) ->
-    Pre = <<123,34,112,114,111,106,101,99,116,105,111,110,34,58,34>>,
-    Suf = <<34,125,10>>,
-    ok_response(<<Pre/binary, Name/binary, Suf/binary>>, activity_json);
-projection_response_for(Name, sx) ->
-    Pre = <<40,112,114,111,106,101,99,116,105,111,110,32,34>>,
-    Suf = <<34,41,10>>,
-    ok_response(<<Pre/binary, Name/binary, Suf/binary>>, sx);
-projection_response_for(Name, cbor) ->
-    ok_response(Name, cbor);
-projection_response_for(Name, _) ->
-    projection_response(Name).
-
-%% projections_list_response — empty-list stub.
-
-projections_list_response_for(text) ->
-    projections_list_response();
-%% `{"projections":[]}\n`
-projections_list_response_for(json) ->
-    Body = <<123,34,112,114,111,106,101,99,116,105,111,110,115,
-             34,58,91,93,125,10>>,
-    ok_response(Body, json);
-projections_list_response_for(activity_json) ->
-    Body = <<123,34,112,114,111,106,101,99,116,105,111,110,115,
-             34,58,91,93,125,10>>,
-    ok_response(Body, activity_json);
-%% `(projections)\n`
-projections_list_response_for(sx) ->
-    Body = <<40,112,114,111,106,101,99,116,105,111,110,115,41,10>>,
-    ok_response(Body, sx);
-projections_list_response_for(cbor) ->
-    [_, _, {body, Body}] = projections_list_response(),
-    ok_response(Body, cbor);
-projections_list_response_for(_) ->
-    projections_list_response().

next/kernel/log.erl

@@ -1,362 +0,0 @@
--module(log).
--export([open/2, open_disk/2, open_disk/3,
-         append/2, tip/1, replay/3, entries/1,
-         segments/1]).
-
-%% Per-actor activity log — the canonical record of everything an
-%% actor has emitted, in chronological order. Per design §15.2 this
-%% lives on disk as numbered segment files; v1 started with an
-%% in-memory backend (Step 3a) so the API + seq-number machinery
-%% could be locked down before on-disk persistence (Step 3b) and
-%% segment rotation (Step 3c.a — this revision).
-%%
-%% On-disk layout:
-%%   <BasePath>/<ActorId>-NNNNNN.log
-%%
-%% NNNNNN is a 6-digit zero-padded segment index (000000..999999) so
-%% file:list_dir's alphabetical ordering coincides with numeric. Each
-%% segment file is the concat of length-prefixed frames; each frame
-%% is `<<Len:32/big>>` + `term_codec:encode(Activity)`.
-%%
-%% In-memory state (a property list):
-%%   [{actor, ActorId},
-%%    {base, BasePath},          %% binary | charlist
-%%    {seq, NextSeq},            %% next seq the log will assign
-%%    {entries, [Activity, ...]}, %% flat, append order, oldest first
-%%    {persisted, true|false},   %% does append write through?
-%%    {seg_size, MaxBytes},      %% rotate when active segment > this
-%%    {seg_lens, [N0, N1, ...]}]  %% entry count per segment in order
-%%
-%% `seg_lens` is the sole bookkeeping needed to compute (a) which
-%% segment any given seq lives in, and (b) which slice of `entries`
-%% is the active segment's contents to rewrite on append. The last
-%% element is the active segment's length.
-
-%% In-memory only — atoms accepted as BasePath for back-compat with
-%% Step 3a tests that just want the API surface.
-open(ActorId, BasePath) ->
-    {ok, [{actor, ActorId}, {base, BasePath},
-          {seq, 0}, {entries, []},
-          {persisted, false}]}.
-
-%% Disk-backed; default segment size = effectively unlimited (no
-%% rotation). Use open_disk/3 with {segment_size, N} to enable.
-open_disk(ActorId, BasePath) ->
-    open_disk(ActorId, BasePath, [{segment_size, 1073741824}]). %% 1 GiB
-
-open_disk(ActorId, BasePath, Opts) ->
-    SegSize = proplist_get(segment_size, Opts, 1073741824),
-    case load_all_segments(ActorId, BasePath) of
-        {ok, SegEntries} ->
-            %% SegEntries :: [[Entry, ...]] in segment-index order
-            %% (empty list when no segments exist on disk).
-            Lens0 = [length(S) || S <- SegEntries],
-            %% Always have at least one active segment, even if empty.
-            Lens = case Lens0 of
-                       [] -> [0];
-                       _ -> Lens0
-                   end,
-            Flat = flatten_segs(SegEntries),
-            State = [{actor, ActorId}, {base, BasePath},
-                     {seq, length(Flat)},
-                     {entries, Flat},
-                     {persisted, true},
-                     {seg_size, SegSize},
-                     {seg_lens, Lens}],
-            {ok, State};
-        {error, _} = E ->
-            E
-    end.
-
-append(LogState, Activity) ->
-    Seq = field(seq, LogState),
-    Entries = field(entries, LogState),
-    case lookup(persisted, LogState) of
-        true ->
-            SegLens = field(seg_lens, LogState),
-            SegSize = field(seg_size, LogState),
-            {NewSegLens, ActiveIdx, ActiveEntries} =
-                place_append(Entries, Activity, SegLens, SegSize),
-            Path = segment_path(field(actor, LogState),
-                                field(base, LogState),
-                                ActiveIdx),
-            ok = write_segment(Path, ActiveEntries),
-            NewState = replace_field(seq, Seq + 1,
-                       replace_field(entries, Entries ++ [Activity],
-                       replace_field(seg_lens, NewSegLens, LogState))),
-            {ok, NewState, Seq};
-        _ ->
-            NewState = replace_field(seq, Seq + 1,
-                       replace_field(entries, Entries ++ [Activity],
-                                     LogState)),
-            {ok, NewState, Seq}
-    end.
-
-tip(LogState) ->
-    field(seq, LogState).
-
-replay(LogState, InitAcc, Fun) ->
-    Entries = field(entries, LogState),
-    replay_loop(Entries, 0, InitAcc, Fun).
-
-entries(LogState) ->
-    field(entries, LogState).
-
-%% Debug accessor: returns the in-memory seg_lens (count per segment
-%% in index order). Used by rotation tests to assert that rotation
-%% happened.
-segments(LogState) ->
-    case lookup(seg_lens, LogState) of
-        undefined -> [];
-        L -> L
-    end.
-
-%% --- internals ---
-
-replay_loop([], _, Acc, _) -> Acc;
-replay_loop([Act | Rest], Seq, Acc, Fun) ->
-    replay_loop(Rest, Seq + 1, Fun(Act, Seq, Acc), Fun).
-
-%% place_append/4 decides whether the new Activity extends the current
-%% active segment or opens a fresh one, returning the resulting
-%% seg_lens, the active segment's index, and the active segment's
-%% complete entry list (the slice that needs to be (re)written to
-%% disk).
-%%
-%% Rotation rule: if the active segment already on disk is at or past
-%% the size threshold (encoded_size(OldActive) >= SegSize) AND it
-%% already holds at least one entry, the new Activity opens a new
-%% segment. A single entry larger than the threshold therefore lives
-%% on its own — we never recurse rotating a one-entry segment.
-%%
-%% This is decided BEFORE the append (looking at the pre-append size),
-%% so each segment file is written exactly once per append cycle.
-place_append(OldEntries, Activity, SegLens, SegSize) ->
-    {Pre, Last} = split_last(SegLens),
-    PreCount = sum(Pre),
-    OldActive = drop(PreCount, OldEntries),
-    OldActiveSize = encoded_size(OldActive),
-    case (OldActiveSize >= SegSize) andalso (Last >= 1) of
-        true ->
-            %% Rotate: new entry starts a brand-new segment.
-            NewSegLens = SegLens ++ [1],
-            NewActiveIdx = length(SegLens),
-            {NewSegLens, NewActiveIdx, [Activity]};
-        false ->
-            %% Stay: extend current active.
-            NewSegLens = Pre ++ [Last + 1],
-            NewActiveIdx = length(Pre),
-            {NewSegLens, NewActiveIdx, OldActive ++ [Activity]}
-    end.
-
-split_last([X]) -> {[], X};
-split_last([H | T]) ->
-    {Tl, Last} = split_last(T),
-    {[H | Tl], Last}.
-
-sum(L) -> sum_(L, 0).
-sum_([], A) -> A;
-sum_([H | T], A) -> sum_(T, A + H).
-
-drop(0, L) -> L;
-drop(_, []) -> [];
-drop(N, [_ | T]) -> drop(N - 1, T).
-
-%% flatten_segs/1 — concat a list of segments (each itself a list of
-%% entries) into a single flat list, preserving order. Used by
-%% open_disk to assemble the on-disk activity history from per-
-%% segment loads. Implemented locally because lists:append/1 isn't
-%% registered in this port — only lists:append/2.
-flatten_segs([]) -> [];
-flatten_segs([Seg | Rest]) -> Seg ++ flatten_segs(Rest).
-
-encoded_size(Entries) ->
-    byte_size(list_to_binary(
-        [frame(term_codec:encode(E)) || E <- Entries])).
-
-%% Try to read every segment file under BasePath matching the actor.
-%% Returns {ok, [[Entry, ...]]} where the outer list is in segment-
-%% index order. Empty when no segments exist.
-load_all_segments(ActorId, BasePath) ->
-    %% list_dir returns {ok, [Binary]} of entry names in sorted order
-    %% per fed-prims contract.
-    BaseChars = base_chars(BasePath),
-    case file:list_dir(BaseChars) of
-        {ok, Names} ->
-            %% Erlang string literals are NOT charlists in this port,
-            %% so build prefix/suffix as explicit char-code lists.
-            Prefix = atom_to_list(ActorId) ++ [$-],
-            Suffix = [$., $l, $o, $g],
-            Indices = collect_segment_indices(Names, Prefix, Suffix),
-            read_segments_in_order(Indices, ActorId, BasePath, []);
-        {error, enoent} ->
-            {ok, []};
-        {error, R} ->
-            {error, {read, R}}
-    end.
-
-collect_segment_indices([], _, _) -> [];
-collect_segment_indices([Name | Rest], Prefix, Suffix) ->
-    case parse_segment_name(Name, Prefix, Suffix) of
-        {ok, N} ->
-            [N | collect_segment_indices(Rest, Prefix, Suffix)];
-        not_ours ->
-            collect_segment_indices(Rest, Prefix, Suffix)
-    end.
-
-parse_segment_name(NameBin, Prefix, Suffix) when is_binary(NameBin) ->
-    parse_segment_name(binary_to_list(NameBin), Prefix, Suffix);
-parse_segment_name(Name, Prefix, Suffix) ->
-    case strip_prefix(Name, Prefix) of
-        {ok, Rest} ->
-            case strip_suffix(Rest, Suffix) of
-                {ok, NumStr} ->
-                    case is_all_digits(NumStr) of
-                        true -> {ok, list_to_integer(NumStr)};
-                        false -> not_ours
-                    end;
-                not_ours -> not_ours
-            end;
-        not_ours -> not_ours
-    end.
-
-strip_prefix(Str, []) -> {ok, Str};
-strip_prefix([C | Rest], [P | PRest]) ->
-    case C =:= P of
-        true -> strip_prefix(Rest, PRest);
-        false -> not_ours
-    end;
-strip_prefix(_, _) -> not_ours.
-
-strip_suffix(Str, Suffix) ->
-    SL = length(Str),
-    XL = length(Suffix),
-    case SL >= XL of
-        true ->
-            Head = take_n_pl(SL - XL, Str),
-            Tail = drop(SL - XL, Str),
-            case Tail =:= Suffix of
-                true -> {ok, Head};
-                false -> not_ours
-            end;
-        false -> not_ours
-    end.
-
-take_n_pl(0, _) -> [];
-take_n_pl(_, []) -> [];
-take_n_pl(N, [H | T]) -> [H | take_n_pl(N - 1, T)].
-
-is_all_digits([]) -> false;
-is_all_digits(Chars) -> all_digits(Chars).
-
-all_digits([]) -> true;
-all_digits([C | Rest]) when C >= $0, C =< $9 -> all_digits(Rest);
-all_digits(_) -> false.
-
-%% read_segments_in_order/4 — fed-prims sorts list_dir alphabetically;
-%% with 6-digit zero-padded names that coincides with numeric order.
-%% But we also accept legacy unpadded names, so sort by index to be
-%% defensive.
-read_segments_in_order(Indices, ActorId, BasePath, Acc) ->
-    Sorted = isort(Indices),
-    read_each(Sorted, ActorId, BasePath, Acc).
-
-read_each([], _, _, Acc) ->
-    {ok, lists:reverse(Acc)};
-read_each([Idx | Rest], ActorId, BasePath, Acc) ->
-    Path = segment_path(ActorId, BasePath, Idx),
-    case try_read_segment(Path) of
-        {ok, Entries} ->
-            read_each(Rest, ActorId, BasePath, [Entries | Acc]);
-        {error, _} = E -> E
-    end.
-
-%% Tiny insertion sort over a small list of integers.
-isort([]) -> [];
-isort([H | T]) -> insert(H, isort(T)).
-insert(X, []) -> [X];
-insert(X, [Y | Rest]) when X =< Y -> [X, Y | Rest];
-insert(X, [Y | Rest]) -> [Y | insert(X, Rest)].
-
-%% segment_path/3 — charlist path to the Idx'th segment file.
-segment_path(ActorId, BasePath, Idx) ->
-    base_chars(BasePath) ++ [$/] ++ atom_to_list(ActorId)
-        ++ [$-] ++ pad_int(Idx, 6) ++ [$., $l, $o, $g].
-
-base_chars(B) when is_binary(B) -> binary_to_list(B);
-base_chars(L) when is_list(L) -> L.
-
-%% Zero-pad an integer to Width digits as a charlist.
-pad_int(N, Width) ->
-    Cs = integer_to_list(N),
-    pad_left(Cs, Width).
-
-pad_left(Cs, Width) ->
-    case length(Cs) >= Width of
-        true -> Cs;
-        false -> pad_left([$0 | Cs], Width)
-    end.
-
-write_segment(Path, Entries) ->
-    Frames = [frame(term_codec:encode(E)) || E <- Entries],
-    file:write_file(Path, list_to_binary(Frames)).
-
-%% frame/1 — prepend 4-byte big-endian length to Payload.
-frame(Payload) when is_binary(Payload) ->
-    L = byte_size(Payload),
-    B3 = (L div 16777216) rem 256,
-    B2 = (L div 65536) rem 256,
-    B1 = (L div 256) rem 256,
-    B0 = L rem 256,
-    [B3, B2, B1, B0, Payload].
-
-try_read_segment(Path) ->
-    case file:read_file(Path) of
-        {ok, Bin} ->
-            try {ok, decode_frames(binary_to_list(Bin), [])}
-            catch
-                throw:Reason -> {error, {corrupt, Reason}};
-                error:Reason -> {error, {corrupt, Reason}}
-            end;
-        {error, enoent} ->
-            {ok, []};
-        {error, R} ->
-            {error, {read, R}}
-    end.
-
-decode_frames([], Acc) ->
-    lists:reverse(Acc);
-decode_frames([B3, B2, B1, B0 | Rest], Acc) ->
-    Len = B3 * 16777216 + B2 * 65536 + B1 * 256 + B0,
-    {Payload, Rest2} = take_n(Len, Rest),
-    case term_codec:decode(list_to_binary(Payload)) of
-        {ok, Term, _} -> decode_frames(Rest2, [Term | Acc]);
-        {error, R} -> throw({decode, R})
-    end;
-decode_frames(_, _) ->
-    throw(truncated_header).
-
-take_n(0, R) -> {[], R};
-take_n(N, [H | T]) ->
-    {Hs, Tl} = take_n(N - 1, T),
-    {[H | Hs], Tl};
-take_n(_, []) ->
-    throw(truncated_body).
-
-%% --- proplist helpers ---
-
-field(K, [{K, V} | _]) -> V;
-field(K, [_ | Rest]) -> field(K, Rest);
-field(_, []) -> erlang:error(badkey).
-
-lookup(K, [{K, V} | _]) -> V;
-lookup(K, [_ | Rest]) -> lookup(K, Rest);
-lookup(_, []) -> undefined.
-
-replace_field(K, V, []) -> [{K, V}];
-replace_field(K, V, [{K, _} | Rest]) -> [{K, V} | Rest];
-replace_field(K, V, [P | Rest]) -> [P | replace_field(K, V, Rest)].
-
-proplist_get(K, [{K, V} | _], _) -> V;
-proplist_get(K, [_ | Rest], Default) -> proplist_get(K, Rest, Default);
-proplist_get(_, [], Default) -> Default.

next/kernel/log_server.erl

@@ -1,85 +0,0 @@
--module(log_server).
--behaviour(gen_server).
--export([start_link/2, start_link/3,
-         append/2, tip/1, entries/1, replay/3,
-         segments/1, stop/1]).
--export([init/1, handle_call/3, handle_cast/2, handle_info/2]).
-
-%% Step 3c.b — gen_server in front of `log` that owns a single
-%% per-actor disk-backed log state and serialises concurrent
-%% appenders through `gen_server:call`.
-%%
-%% Architecture: the pure `log` module from Step 3c.a remains the
-%% canonical substrate (open_disk, append, tip, replay, entries,
-%% segments). This wrapper owns one log state per process; every
-%% public op (append/tip/entries/replay/segments) routes through
-%% gen_server:call so that the on-disk segment writer sees one
-%% append at a time, regardless of how many writer processes are
-%% pushing concurrently.
-%%
-%% Port notes carried from Step 5b's registry_server:
-%%   * `gen_server:start_link/2` returns the raw Pid, not `{ok,Pid}`.
-%%   * Spawned processes don't survive across separate
-%%     `erlang-eval-ast` invocations — every concurrency test has
-%%     to start the server, spin writers, join them, and assert all
-%%     within one eval expression.
-%%
-%% API takes the server Pid (not a registered name) so multiple
-%% per-actor servers can coexist without colliding on the registry.
-
-%% --- public API ---
-
-start_link(ActorId, BasePath) ->
-    gen_server:start_link(log_server, [ActorId, BasePath, []]).
-
-start_link(ActorId, BasePath, Opts) ->
-    gen_server:start_link(log_server, [ActorId, BasePath, Opts]).
-
-append(Pid, Activity) ->
-    gen_server:call(Pid, {append, Activity}).
-
-tip(Pid) ->
-    gen_server:call(Pid, tip).
-
-entries(Pid) ->
-    gen_server:call(Pid, entries).
-
-replay(Pid, InitAcc, Fun) ->
-    %% The fold runs server-side so the state stays consistent
-    %% with concurrent writers; the caller's Fun is closed over
-    %% the message and shipped opaque through gen_server:call.
-    gen_server:call(Pid, {replay, InitAcc, Fun}).
-
-segments(Pid) ->
-    gen_server:call(Pid, segments).
-
-stop(Pid) ->
-    gen_server:call(Pid, '$gen_stop').
-
-%% --- gen_server callbacks ---
-
-init([ActorId, BasePath, Opts]) ->
-    case Opts of
-        [] ->
-            {ok, LogState} = log:open_disk(ActorId, BasePath),
-            {ok, LogState};
-        _ ->
-            {ok, LogState} = log:open_disk(ActorId, BasePath, Opts),
-            {ok, LogState}
-    end.
-
-handle_call({append, Activity}, _From, State) ->
-    {ok, NewState, Seq} = log:append(State, Activity),
-    {reply, {ok, Seq}, NewState};
-handle_call(tip, _From, State) ->
-    {reply, log:tip(State), State};
-handle_call(entries, _From, State) ->
-    {reply, log:entries(State), State};
-handle_call({replay, InitAcc, Fun}, _From, State) ->
-    {reply, log:replay(State, InitAcc, Fun), State};
-handle_call(segments, _From, State) ->
-    {reply, log:segments(State), State}.
-
-handle_cast(_, S) -> {noreply, S}.
-
-handle_info(_, S) -> {noreply, S}.

next/kernel/nx_cid.erl

@@ -1,24 +0,0 @@
--module(nx_cid).
--export([from_sx/1, to_string/1, from_string/1, equals/2]).
-
-%% The kernel-side CID wrapper. The host BIF `cid:to_string/1` already
-%% produces a canonical CIDv1 (raw codec, sha2-256 multihash) over the
-%% deterministic textual form of any term (er-format-value); we expose
-%% it under the kernel namespace and add the equality + round-trip
-%% helpers the rest of the kernel needs.
-%%
-%% Naming note: the BIF module is `cid`, so we use `nx_cid` to avoid
-%% shadowing. Plans/fed-sx-milestone-1.md §Step 1 spells the file as
-%% `cid.erl`; the briefing flags Erlang snippets as illustrative.
-
-from_sx(V) ->
-    cid:to_string(V).
-
-to_string(Cid) ->
-    Cid.
-
-from_string(S) ->
-    S.
-
-equals(A, B) ->
-    A =:= B.

next/kernel/nx_kernel.erl

@@ -1,139 +0,0 @@
--module(nx_kernel).
--behaviour(gen_server).
--export([new/3, publish/2,
-         actor_id/1, log_state/1, log_tip/1,
-         key_spec/1, actor_state/1, projections/1,
-         next_published/1, with_projections/2]).
--export([start_link/3, publish/1, query/0, log_tip/0,
-         with_projections/1, stop/0]).
--export([init/1, handle_call/3, handle_cast/2, handle_info/2]).
-
-%% Kernel orchestrator — the long-lived runtime state held by the
-%% running fed-sx instance. The HTTP layer (Step 8c-post-publish
-%% follow-up) will park this in a gen_server and dispatch the POST
-%% /activity request through `publish/2`.
-%%
-%% State shape (property list):
-%%   [{actor_id, A},
-%%    {key_spec, KS},          % proplist: key_id / algorithm / value
-%%    {actor_state, AS},       % proplist: public_keys
-%%    {log, L},                % log:open/2 return value
-%%    {projections, [Name]},   % list of registered projection process names
-%%    {next_published, N}]     % monotonic counter we feed as :published
-%%
-%% Step 6c's stage_replay catches duplicates by `:id`; the `:id`
-%% is derived from the unsigned envelope contents. Same Request +
-%% same `:published` -> same CID, so the next_published counter
-%% gives every publish a distinct timestamp without needing a
-%% wall-clock BIF.
-
-new(ActorId, KeySpec, ActorStateProplist) ->
-    {ok, L0} = log:open(ActorId, base_stub()),
-    [{actor_id, ActorId},
-     {key_spec, KeySpec},
-     {actor_state, ActorStateProplist},
-     {log, L0},
-     {projections, []},
-     {next_published, 1}].
-
-%% publish/2 — pure state transition. Returns either:
-%%   {ok, Result, NewState}   — log + counter advanced
-%%   {error, Reason, State}   — state unchanged on validation halt
-publish(Request, State) ->
-    P   = field(next_published, State),
-    Ctx = [{actor_id,    field(actor_id, State)},
-           {published,   P},
-           {key_spec,    field(key_spec, State)},
-           {actor_state, field(actor_state, State)},
-           {log,         field(log, State)},
-           {projections, field(projections, State)}],
-    case outbox:publish(Request, Ctx) of
-        {ok, Result, NewLog} ->
-            State1 = set(log, NewLog, State),
-            State2 = set(next_published, P + 1, State1),
-            {ok, Result, State2};
-        {error, Reason, _} ->
-            {error, Reason, State}
-    end.
-
-%% Accessors
-
-actor_id(State)        -> field(actor_id, State).
-key_spec(State)        -> field(key_spec, State).
-actor_state(State)     -> field(actor_state, State).
-log_state(State)       -> field(log, State).
-log_tip(State)         -> log:tip(field(log, State)).
-projections(State)     -> field(projections, State).
-next_published(State)  -> field(next_published, State).
-
-%% with_projections — return a new state with :projections replaced.
-with_projections(Names, State) ->
-    set(projections, Names, State).
-
-%% Internal
-
-%% "base_stub" — placeholder base path for the in-memory log
-%% in v1 (the in-memory log ignores the base argument).
-base_stub() ->
-    <<98,97,115,101,95,115,116,117,98>>.
-
-field(K, [{K, V} | _]) -> V;
-field(K, [_ | Rest]) -> field(K, Rest);
-field(_, []) -> nil.
-
-set(K, V, []) -> [{K, V}];
-set(K, V, [{K, _} | Rest]) -> [{K, V} | Rest];
-set(K, V, [P | Rest]) -> [P | set(K, V, Rest)].
-
-%% ── gen_server wrapper ──────────────────────────────────────────
-%%
-%% Mirrors the registry / projection gen_server patterns from
-%% Steps 5b and 7b. Same port quirks: raw Pid return, no `?MODULE`
-%% macro, spawned processes don't persist across separate
-%% erlang-eval-ast calls — tests inline start_link with operations.
-
-start_link(ActorId, KeySpec, ActorStateProplist) ->
-    Pid = gen_server:start_link(nx_kernel,
-            [ActorId, KeySpec, ActorStateProplist]),
-    erlang:register(nx_kernel, Pid),
-    Pid.
-
-stop() ->
-    R = gen_server:call(nx_kernel, '$gen_stop'),
-    erlang:unregister(nx_kernel),
-    R.
-
-publish(Request) ->
-    gen_server:call(nx_kernel, {publish, Request}).
-
-query() ->
-    gen_server:call(nx_kernel, get_state).
-
-log_tip() ->
-    gen_server:call(nx_kernel, get_log_tip).
-
-with_projections(Names) ->
-    gen_server:call(nx_kernel, {set_projections, Names}).
-
-%% gen_server callbacks
-
-init([ActorId, KeySpec, AS]) ->
-    {ok, new(ActorId, KeySpec, AS)}.
-
-handle_call({publish, Request}, _From, State) ->
-    case publish(Request, State) of
-        {ok, Result, NewState} ->
-            {reply, {ok, Result}, NewState};
-        {error, Reason, SameState} ->
-            {reply, {error, Reason}, SameState}
-    end;
-handle_call(get_state, _From, State) ->
-    {reply, State, State};
-handle_call(get_log_tip, _From, State) ->
-    {reply, log_tip(State), State};
-handle_call({set_projections, Names}, _From, State) ->
-    {reply, ok, with_projections(Names, State)}.
-
-handle_cast(_, S) -> {noreply, S}.
-
-handle_info(_, S) -> {noreply, S}.