Merge loops/erlang into architecture — 530/530 tests, all phases complete

lib/erlang/bench_ring.sh

@@ -0,0 +1,86 @@
+#!/usr/bin/env bash
+# Erlang-on-SX ring benchmark.
+#
+# Spawns N processes in a ring, passes a token N hops (one full round),
+# and reports wall-clock time + throughput. Aspirational target from
+# the plan is 1M processes; current sync-scheduler architecture caps out
+# orders of magnitude lower — this script measures honestly across a
+# range of N so the result/scaling is recorded.
+#
+# Usage:
+#   bash lib/erlang/bench_ring.sh                # default ladder
+#   bash lib/erlang/bench_ring.sh 100 1000 5000  # custom Ns
+
+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
+
+if [ "$#" -gt 0 ]; then
+  NS=("$@")
+else
+  NS=(10 100 500 1000)
+fi
+
+TMPFILE=$(mktemp)
+trap "rm -f $TMPFILE" EXIT
+
+# One-line Erlang program. Replaces __N__ with the size for each run.
+PROGRAM='Me = self(), N = __N__, Spawner = fun () -> receive {setup, Next} -> Loop = fun () -> receive {token, 0, Parent} -> Parent ! done; {token, K, Parent} -> Next ! {token, K-1, Parent}, Loop() end end, Loop() end end, BuildRing = fun (K, Acc) -> if K =:= 0 -> Acc; true -> BuildRing(K-1, [spawn(Spawner) | Acc]) end end, Pids = BuildRing(N, []), Wire = fun (Ps) -> case Ps of [P, Q | _] -> P ! {setup, Q}, Wire(tl(Ps)); [Last] -> Last ! {setup, hd(Pids)} end end, Wire(Pids), hd(Pids) ! {token, N, Me}, receive done -> done end'
+
+run_n() {
+  local n="$1"
+  local prog="${PROGRAM//__N__/$n}"
+  cat > "$TMPFILE" <<EPOCHS
+(epoch 1)
+(load "lib/erlang/tokenizer.sx")
+(load "lib/erlang/parser.sx")
+(load "lib/erlang/parser-core.sx")
+(load "lib/erlang/parser-expr.sx")
+(load "lib/erlang/parser-module.sx")
+(load "lib/erlang/transpile.sx")
+(load "lib/erlang/runtime.sx")
+(epoch 2)
+(eval "(erlang-eval-ast \"${prog//\"/\\\"}\")")
+EPOCHS
+
+  local start_s start_ns end_s end_ns elapsed_ms
+  start_s=$(date +%s)
+  start_ns=$(date +%N)
+  out=$(timeout 300 "$SX_SERVER" < "$TMPFILE" 2>&1)
+  end_s=$(date +%s)
+  end_ns=$(date +%N)
+
+  local ok="false"
+  if echo "$out" | grep -q ':name "done"'; then ok="true"; fi
+
+  # ms = (end_s - start_s)*1000 + (end_ns - start_ns)/1e6
+  elapsed_ms=$(awk -v s1="$start_s" -v n1="$start_ns" -v s2="$end_s" -v n2="$end_ns" \
+    'BEGIN { printf "%d", (s2 - s1) * 1000 + (n2 - n1) / 1000000 }')
+
+  if [ "$ok" = "true" ]; then
+    local hops_per_s
+    hops_per_s=$(awk -v n="$n" -v ms="$elapsed_ms" \
+      'BEGIN { if (ms == 0) ms = 1; printf "%.0f", n * 1000 / ms }')
+    printf "  N=%-8s  hops=%-8s  %sms  (%s hops/s)\n" "$n" "$n" "$elapsed_ms" "$hops_per_s"
+  else
+    printf "  N=%-8s  FAILED  %sms\n" "$n" "$elapsed_ms"
+  fi
+}
+
+echo "Ring benchmark — sx_server.exe (synchronous scheduler)"
+echo
+for n in "${NS[@]}"; do
+  run_n "$n"
+done
+echo
+echo "Note: 1M-process target from the plan is aspirational; the synchronous"
+echo "scheduler with shift-based suspension and dict-based env copies is not"
+echo "engineered for that scale. Numbers above are honest baselines."

lib/erlang/bench_ring_results.md

@@ -0,0 +1,35 @@
+# Ring Benchmark Results
+
+Generated by `lib/erlang/bench_ring.sh` against `sx_server.exe` on the
+synchronous Erlang-on-SX scheduler.
+
+| N (processes) | Hops | Wall-clock | Throughput |
+|---|---|---|---|
+| 10 | 10 | 907ms | 11 hops/s |
+| 50 | 50 | 2107ms | 24 hops/s |
+| 100 | 100 | 3827ms | 26 hops/s |
+| 500 | 500 | 17004ms | 29 hops/s |
+| 1000 | 1000 | 29832ms | 34 hops/s |
+
+(Each `Nm` row spawns N processes connected in a ring and passes a
+single token N hops total — i.e. the token completes one full lap.)
+
+## Status of the 1M-process target
+
+Phase 3's stretch goal in `plans/erlang-on-sx.md` is a million-process
+ring benchmark. **That target is not met** in the current synchronous
+scheduler; extrapolating from the table above, 1M hops would take
+~30 000 s. Correctness is fine — the program runs at every measured
+size — but throughput is bound by per-hop overhead.
+
+Per-hop cost is dominated by:
+- `er-env-copy` per fun clause attempt (whole-dict copy each time)
+- `call/cc` capture + `raise`/`guard` unwind on every `receive`
+- `er-q-delete-at!` rebuilds the mailbox backing list on every match
+- `dict-set!`/`dict-has?` lookups in the global processes table
+
+To reach 1M-process throughput in this architecture would need at
+least: persistent (path-copying) envs, an inline scheduler that
+doesn't call/cc on the common path (msg-already-in-mailbox), and a
+linked-list mailbox. None of those are in scope for the Phase 3
+checkbox — captured here as the floor we're starting from.

lib/erlang/conformance.sh

@@ -0,0 +1,153 @@
+#!/usr/bin/env bash
+# Erlang-on-SX conformance runner.
+#
+# Loads every erlang test suite via the epoch protocol, collects
+# pass/fail counts, and writes lib/erlang/scoreboard.json + .md.
+#
+# Usage:
+#   bash lib/erlang/conformance.sh           # run all suites
+#   bash lib/erlang/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 $OUTFILE" EXIT
+
+# Each suite: name | counter pass | counter total
+SUITES=(
+  "tokenize|er-test-pass|er-test-count"
+  "parse|er-parse-test-pass|er-parse-test-count"
+  "eval|er-eval-test-pass|er-eval-test-count"
+  "runtime|er-rt-test-pass|er-rt-test-count"
+  "ring|er-ring-test-pass|er-ring-test-count"
+  "ping-pong|er-pp-test-pass|er-pp-test-count"
+  "bank|er-bank-test-pass|er-bank-test-count"
+  "echo|er-echo-test-pass|er-echo-test-count"
+  "fib|er-fib-test-pass|er-fib-test-count"
+)
+
+cat > "$TMPFILE" << 'EPOCHS'
+(epoch 1)
+(load "lib/erlang/tokenizer.sx")
+(load "lib/erlang/parser.sx")
+(load "lib/erlang/parser-core.sx")
+(load "lib/erlang/parser-expr.sx")
+(load "lib/erlang/parser-module.sx")
+(load "lib/erlang/transpile.sx")
+(load "lib/erlang/runtime.sx")
+(load "lib/erlang/tests/tokenize.sx")
+(load "lib/erlang/tests/parse.sx")
+(load "lib/erlang/tests/eval.sx")
+(load "lib/erlang/tests/runtime.sx")
+(load "lib/erlang/tests/programs/ring.sx")
+(load "lib/erlang/tests/programs/ping_pong.sx")
+(load "lib/erlang/tests/programs/bank.sx")
+(load "lib/erlang/tests/programs/echo.sx")
+(load "lib/erlang/tests/programs/fib_server.sx")
+(epoch 100)
+(eval "(list er-test-pass er-test-count)")
+(epoch 101)
+(eval "(list er-parse-test-pass er-parse-test-count)")
+(epoch 102)
+(eval "(list er-eval-test-pass er-eval-test-count)")
+(epoch 103)
+(eval "(list er-rt-test-pass er-rt-test-count)")
+(epoch 104)
+(eval "(list er-ring-test-pass er-ring-test-count)")
+(epoch 105)
+(eval "(list er-pp-test-pass er-pp-test-count)")
+(epoch 106)
+(eval "(list er-bank-test-pass er-bank-test-count)")
+(epoch 107)
+(eval "(list er-echo-test-pass er-echo-test-count)")
+(epoch 108)
+(eval "(list er-fib-test-pass er-fib-test-count)")
+EPOCHS
+
+timeout 120 "$SX_SERVER" < "$TMPFILE" > "$OUTFILE" 2>&1
+
+# Parse "(N M)" from the line after each "(ok-len <epoch> ...)" marker.
+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=$((idx + 1))
+done
+
+printf '\nErlang-on-SX conformance: %d / %d\n' "$TOTAL_PASS" "$TOTAL_COUNT"
+
+# scoreboard.json
+cat > lib/erlang/scoreboard.json <<JSON
+{
+  "language": "erlang",
+  "total_pass": $TOTAL_PASS,
+  "total": $TOTAL_COUNT,
+  "suites": [$JSON_SUITES
+  ]
+}
+JSON
+
+# scoreboard.md
+cat > lib/erlang/scoreboard.md <<MD
+# Erlang-on-SX Scoreboard
+
+**Total: ${TOTAL_PASS} / ${TOTAL_COUNT} tests passing**
+
+|  | Suite | Pass | Total |
+|---|---|---|---|
+$MD_ROWS
+
+Generated by \`lib/erlang/conformance.sh\`.
+MD
+
+if [ "$TOTAL_PASS" -eq "$TOTAL_COUNT" ]; then
+  exit 0
+else
+  exit 1
+fi

lib/erlang/parser-expr.sx

@@ -237,6 +237,8 @@
         (er-parse-fun-expr st)
         (er-is? st "keyword" "try")
         (er-parse-try st)
+        (er-is? st "punct" "<<")
+        (er-parse-binary st)
         :else (error
           (str
             "Erlang parse: unexpected "
@@ -281,12 +283,56 @@
   (fn
     (st)
     (er-expect! st "punct" "[")
-    (if
+    (cond
       (er-is? st "punct" "]")
       (do (er-advance! st) {:type "nil"})
-      (let
-        ((elems (list (er-parse-expr-prec st 0))))
-        (er-parse-list-tail st elems)))))
+      :else (let
+        ((first (er-parse-expr-prec st 0)))
+        (cond
+          (er-is? st "punct" "||") (er-parse-list-comp st first)
+          :else (er-parse-list-tail st (list first)))))))
+
+(define
+  er-parse-list-comp
+  (fn
+    (st head)
+    (er-advance! st)
+    (let
+      ((quals (list (er-parse-lc-qualifier st))))
+      (er-parse-list-comp-tail st head quals))))
+
+(define
+  er-parse-list-comp-tail
+  (fn
+    (st head quals)
+    (cond
+      (er-is? st "punct" ",")
+      (do
+        (er-advance! st)
+        (append! quals (er-parse-lc-qualifier st))
+        (er-parse-list-comp-tail st head quals))
+      (er-is? st "punct" "]")
+      (do (er-advance! st) {:head head :qualifiers quals :type "lc"})
+      :else (error
+        (str
+          "Erlang parse: expected ',' or ']' in list comprehension, got '"
+          (er-cur-value st)
+          "'")))))
+
+(define
+  er-parse-lc-qualifier
+  (fn
+    (st)
+    (let
+      ((e (er-parse-expr-prec st 0)))
+      (cond
+        (er-is? st "punct" "<-")
+        (do
+          (er-advance! st)
+          (let
+            ((source (er-parse-expr-prec st 0)))
+            {:kind "gen" :pattern e :source source}))
+        :else {:kind "filter" :expr e}))))
 
 (define
   er-parse-list-tail
@@ -532,3 +578,63 @@
           ((guards (if (er-is? st "keyword" "when") (do (er-advance! st) (er-parse-guards st)) (list))))
           (er-expect! st "punct" "->")
           (let ((body (er-parse-body st))) {:pattern pat :body body :class klass :guards guards}))))))
+
+;; ── binary literals / patterns ────────────────────────────────
+;; `<< [Seg {, Seg}] >>` where Seg = Value [: Size] [/ Spec]. Size is
+;; a literal integer (multiple of 8 supported); Spec is `integer`
+;; (default) or `binary` (rest-of-binary tail). Sufficient for the
+;; common `<<A:8, B:16, Rest/binary>>` patterns.
+(define
+  er-parse-binary
+  (fn
+    (st)
+    (er-expect! st "punct" "<<")
+    (cond
+      (er-is? st "punct" ">>")
+      (do (er-advance! st) {:segments (list) :type "binary"})
+      :else (let
+        ((segs (list (er-parse-binary-segment st))))
+        (er-parse-binary-tail st segs)))))
+
+(define
+  er-parse-binary-tail
+  (fn
+    (st segs)
+    (cond
+      (er-is? st "punct" ",")
+      (do
+        (er-advance! st)
+        (append! segs (er-parse-binary-segment st))
+        (er-parse-binary-tail st segs))
+      (er-is? st "punct" ">>")
+      (do (er-advance! st) {:segments segs :type "binary"})
+      :else (error
+        (str
+          "Erlang parse: expected ',' or '>>' in binary, got '"
+          (er-cur-value st)
+          "'")))))
+
+(define
+  er-parse-binary-segment
+  (fn
+    (st)
+    ;; Use `er-parse-primary` for the value so a leading `:` falls
+    ;; through to the segment's size suffix instead of being eaten
+    ;; by `er-parse-postfix-loop` as a `Mod:Fun` remote call.
+    (let
+      ((v (er-parse-primary st)))
+      (let
+        ((size (cond
+                 (er-is? st "punct" ":")
+                 (do (er-advance! st) (er-parse-primary st))
+                 :else nil))
+          (spec (cond
+                  (er-is? st "op" "/")
+                  (do
+                    (er-advance! st)
+                    (let
+                      ((tok (er-cur st)))
+                      (er-advance! st)
+                      (get tok :value)))
+                  :else "integer")))
+        {:size size :spec spec :value v}))))

lib/erlang/scoreboard.json

@@ -0,0 +1,16 @@
+{
+  "language": "erlang",
+  "total_pass": 530,
+  "total": 530,
+  "suites": [
+    {"name":"tokenize","pass":62,"total":62,"status":"ok"},
+    {"name":"parse","pass":52,"total":52,"status":"ok"},
+    {"name":"eval","pass":346,"total":346,"status":"ok"},
+    {"name":"runtime","pass":39,"total":39,"status":"ok"},
+    {"name":"ring","pass":4,"total":4,"status":"ok"},
+    {"name":"ping-pong","pass":4,"total":4,"status":"ok"},
+    {"name":"bank","pass":8,"total":8,"status":"ok"},
+    {"name":"echo","pass":7,"total":7,"status":"ok"},
+    {"name":"fib","pass":8,"total":8,"status":"ok"}
+  ]
+}

lib/erlang/scoreboard.md

@@ -0,0 +1,18 @@
+# Erlang-on-SX Scoreboard
+
+**Total: 530 / 530 tests passing**
+
+|  | Suite | Pass | Total |
+|---|---|---|---|
+| ✅ | tokenize | 62 | 62 |
+| ✅ | parse | 52 | 52 |
+| ✅ | eval | 346 | 346 |
+| ✅ | runtime | 39 | 39 |
+| ✅ | ring | 4 | 4 |
+| ✅ | ping-pong | 4 | 4 |
+| ✅ | bank | 8 | 8 |
+| ✅ | echo | 7 | 7 |
+| ✅ | fib | 8 | 8 |
+
+
+Generated by `lib/erlang/conformance.sh`.

lib/erlang/tests/programs/bank.sx

@@ -0,0 +1,159 @@
+;; Bank account server — stateful process, balance threaded through
+;; recursive loop. Handles {deposit, Amt, From}, {withdraw, Amt, From},
+;; {balance, From}, stop. Tests stateful process patterns.
+
+(define er-bank-test-count 0)
+(define er-bank-test-pass 0)
+(define er-bank-test-fails (list))
+
+(define
+  er-bank-test
+  (fn
+    (name actual expected)
+    (set! er-bank-test-count (+ er-bank-test-count 1))
+    (if
+      (= actual expected)
+      (set! er-bank-test-pass (+ er-bank-test-pass 1))
+      (append! er-bank-test-fails {:actual actual :expected expected :name name}))))
+
+(define bank-ev erlang-eval-ast)
+
+;; Server fun shared by all tests — threaded via the program string.
+(define
+  er-bank-server-src
+  "Server = fun (Balance) ->
+     receive
+       {deposit, Amt, From} -> From ! ok, Server(Balance + Amt);
+       {withdraw, Amt, From} ->
+         if Amt > Balance -> From ! insufficient, Server(Balance);
+            true -> From ! ok, Server(Balance - Amt)
+         end;
+       {balance, From} -> From ! Balance, Server(Balance);
+       stop -> ok
+     end
+   end")
+
+;; Open account, deposit, check balance.
+(er-bank-test
+  "deposit 100 -> balance 100"
+  (bank-ev
+    (str
+      er-bank-server-src
+      ", Me = self(),
+       Bank = spawn(fun () -> Server(0) end),
+       Bank ! {deposit, 100, Me},
+       receive ok -> ok end,
+       Bank ! {balance, Me},
+       receive B -> Bank ! stop, B end"))
+  100)
+
+;; Multiple deposits accumulate.
+(er-bank-test
+  "deposits accumulate"
+  (bank-ev
+    (str
+      er-bank-server-src
+      ", Me = self(),
+       Bank = spawn(fun () -> Server(0) end),
+       Bank ! {deposit, 50, Me}, receive ok -> ok end,
+       Bank ! {deposit, 25, Me}, receive ok -> ok end,
+       Bank ! {deposit, 10, Me}, receive ok -> ok end,
+       Bank ! {balance, Me},
+       receive B -> Bank ! stop, B end"))
+  85)
+
+;; Withdraw within balance succeeds; insufficient gets rejected.
+(er-bank-test
+  "withdraw within balance"
+  (bank-ev
+    (str
+      er-bank-server-src
+      ", Me = self(),
+       Bank = spawn(fun () -> Server(100) end),
+       Bank ! {withdraw, 30, Me}, receive ok -> ok end,
+       Bank ! {balance, Me},
+       receive B -> Bank ! stop, B end"))
+  70)
+
+(er-bank-test
+  "withdraw insufficient"
+  (get
+    (bank-ev
+      (str
+        er-bank-server-src
+        ", Me = self(),
+         Bank = spawn(fun () -> Server(20) end),
+         Bank ! {withdraw, 100, Me},
+         receive R -> Bank ! stop, R end"))
+    :name)
+  "insufficient")
+
+;; State preserved across an insufficient withdrawal.
+(er-bank-test
+  "state preserved on rejection"
+  (bank-ev
+    (str
+      er-bank-server-src
+      ", Me = self(),
+       Bank = spawn(fun () -> Server(50) end),
+       Bank ! {withdraw, 1000, Me}, receive _ -> ok end,
+       Bank ! {balance, Me},
+       receive B -> Bank ! stop, B end"))
+  50)
+
+;; Mixed deposits and withdrawals.
+(er-bank-test
+  "mixed transactions"
+  (bank-ev
+    (str
+      er-bank-server-src
+      ", Me = self(),
+       Bank = spawn(fun () -> Server(100) end),
+       Bank ! {deposit, 50, Me}, receive ok -> ok end,
+       Bank ! {withdraw, 30, Me}, receive ok -> ok end,
+       Bank ! {deposit, 10, Me}, receive ok -> ok end,
+       Bank ! {withdraw, 5, Me}, receive ok -> ok end,
+       Bank ! {balance, Me},
+       receive B -> Bank ! stop, B end"))
+  125)
+
+;; Server.stop terminates the bank cleanly — main can verify by
+;; sending stop and then exiting normally.
+(er-bank-test
+  "server stops cleanly"
+  (get
+    (bank-ev
+      (str
+        er-bank-server-src
+        ", Me = self(),
+         Bank = spawn(fun () -> Server(0) end),
+         Bank ! stop,
+         done"))
+    :name)
+  "done")
+
+;; Two clients sharing one bank — interleaved transactions.
+(er-bank-test
+  "two clients share bank"
+  (bank-ev
+    (str
+      er-bank-server-src
+      ", Me = self(),
+       Bank = spawn(fun () -> Server(0) end),
+       Client = fun (Amt) ->
+         spawn(fun () ->
+           Bank ! {deposit, Amt, self()},
+           receive ok -> Me ! deposited end
+         end)
+       end,
+       Client(40),
+       Client(60),
+       receive deposited -> ok end,
+       receive deposited -> ok end,
+       Bank ! {balance, Me},
+       receive B -> Bank ! stop, B end"))
+  100)
+
+(define
+  er-bank-test-summary
+  (str "bank " er-bank-test-pass "/" er-bank-test-count))

lib/erlang/tests/programs/echo.sx

@@ -0,0 +1,140 @@
+;; Echo server — minimal classic Erlang server. Receives {From, Msg}
+;; and sends Msg back to From, then loops. `stop` ends the server.
+
+(define er-echo-test-count 0)
+(define er-echo-test-pass 0)
+(define er-echo-test-fails (list))
+
+(define
+  er-echo-test
+  (fn
+    (name actual expected)
+    (set! er-echo-test-count (+ er-echo-test-count 1))
+    (if
+      (= actual expected)
+      (set! er-echo-test-pass (+ er-echo-test-pass 1))
+      (append! er-echo-test-fails {:actual actual :expected expected :name name}))))
+
+(define echo-ev erlang-eval-ast)
+
+(define
+  er-echo-server-src
+  "EchoSrv = fun () ->
+     Loop = fun () ->
+       receive
+         {From, Msg} -> From ! Msg, Loop();
+         stop -> ok
+       end
+     end,
+     Loop()
+   end")
+
+;; Single round-trip with an atom.
+(er-echo-test
+  "atom round-trip"
+  (get
+    (echo-ev
+      (str
+        er-echo-server-src
+        ", Me = self(),
+         Echo = spawn(EchoSrv),
+         Echo ! {Me, hello},
+         receive R -> Echo ! stop, R end"))
+    :name)
+  "hello")
+
+;; Number round-trip.
+(er-echo-test
+  "number round-trip"
+  (echo-ev
+    (str
+      er-echo-server-src
+      ", Me = self(),
+       Echo = spawn(EchoSrv),
+       Echo ! {Me, 42},
+       receive R -> Echo ! stop, R end"))
+  42)
+
+;; Tuple round-trip — pattern-match the reply to extract V.
+(er-echo-test
+  "tuple round-trip"
+  (echo-ev
+    (str
+      er-echo-server-src
+      ", Me = self(),
+       Echo = spawn(EchoSrv),
+       Echo ! {Me, {ok, 7}},
+       receive {ok, V} -> Echo ! stop, V end"))
+  7)
+
+;; List round-trip.
+(er-echo-test
+  "list round-trip"
+  (echo-ev
+    (str
+      er-echo-server-src
+      ", Me = self(),
+       Echo = spawn(EchoSrv),
+       Echo ! {Me, [1, 2, 3]},
+       receive [H | _] -> Echo ! stop, H end"))
+  1)
+
+;; Multiple sequential round-trips.
+(er-echo-test
+  "three round-trips"
+  (echo-ev
+    (str
+      er-echo-server-src
+      ", Me = self(),
+       Echo = spawn(EchoSrv),
+       Echo ! {Me, 10}, A = receive Ra -> Ra end,
+       Echo ! {Me, 20}, B = receive Rb -> Rb end,
+       Echo ! {Me, 30}, C = receive Rc -> Rc end,
+       Echo ! stop,
+       A + B + C"))
+  60)
+
+;; Two clients sharing one echo server. Each gets its own reply.
+(er-echo-test
+  "two clients"
+  (get
+    (echo-ev
+      (str
+        er-echo-server-src
+        ", Me = self(),
+         Echo = spawn(EchoSrv),
+         Client = fun (Tag) ->
+           spawn(fun () ->
+             Echo ! {self(), Tag},
+             receive R -> Me ! {got, R} end
+           end)
+         end,
+         Client(a),
+         Client(b),
+         receive {got, _} -> ok end,
+         receive {got, _} -> ok end,
+         Echo ! stop,
+         finished"))
+    :name)
+  "finished")
+
+;; Echo via io trace — verify each message round-trips through.
+(er-echo-test
+  "trace 4 messages"
+  (do
+    (er-io-flush!)
+    (echo-ev
+      (str
+        er-echo-server-src
+        ", Me = self(),
+         Echo = spawn(EchoSrv),
+         Send = fun (V) -> Echo ! {Me, V}, receive R -> io:format(\"~p \", [R]) end end,
+         Send(1), Send(2), Send(3), Send(4),
+         Echo ! stop,
+         done"))
+    (er-io-buffer-content))
+  "1 2 3 4 ")
+
+(define
+  er-echo-test-summary
+  (str "echo " er-echo-test-pass "/" er-echo-test-count))

lib/erlang/tests/programs/fib_server.sx

@@ -0,0 +1,152 @@
+;; Fib server — long-lived process that computes fibonacci numbers on
+;; request. Tests recursive function evaluation inside a server loop.
+
+(define er-fib-test-count 0)
+(define er-fib-test-pass 0)
+(define er-fib-test-fails (list))
+
+(define
+  er-fib-test
+  (fn
+    (name actual expected)
+    (set! er-fib-test-count (+ er-fib-test-count 1))
+    (if
+      (= actual expected)
+      (set! er-fib-test-pass (+ er-fib-test-pass 1))
+      (append! er-fib-test-fails {:actual actual :expected expected :name name}))))
+
+(define fib-ev erlang-eval-ast)
+
+;; Fib + server-loop source. Standalone so each test can chain queries.
+(define
+  er-fib-server-src
+  "Fib = fun (0) -> 0; (1) -> 1; (N) -> Fib(N-1) + Fib(N-2) end,
+   FibSrv = fun () ->
+     Loop = fun () ->
+       receive
+         {fib, N, From} -> From ! Fib(N), Loop();
+         stop -> ok
+       end
+     end,
+     Loop()
+   end")
+
+;; Base cases.
+(er-fib-test
+  "fib(0)"
+  (fib-ev
+    (str
+      er-fib-server-src
+      ", Me = self(),
+       Srv = spawn(FibSrv),
+       Srv ! {fib, 0, Me},
+       receive R -> Srv ! stop, R end"))
+  0)
+
+(er-fib-test
+  "fib(1)"
+  (fib-ev
+    (str
+      er-fib-server-src
+      ", Me = self(),
+       Srv = spawn(FibSrv),
+       Srv ! {fib, 1, Me},
+       receive R -> Srv ! stop, R end"))
+  1)
+
+;; Larger values.
+(er-fib-test
+  "fib(10) = 55"
+  (fib-ev
+    (str
+      er-fib-server-src
+      ", Me = self(),
+       Srv = spawn(FibSrv),
+       Srv ! {fib, 10, Me},
+       receive R -> Srv ! stop, R end"))
+  55)
+
+(er-fib-test
+  "fib(15) = 610"
+  (fib-ev
+    (str
+      er-fib-server-src
+      ", Me = self(),
+       Srv = spawn(FibSrv),
+       Srv ! {fib, 15, Me},
+       receive R -> Srv ! stop, R end"))
+  610)
+
+;; Multiple sequential queries to one server. Sum to avoid dict-equality.
+(er-fib-test
+  "sequential fib(5..8) sum"
+  (fib-ev
+    (str
+      er-fib-server-src
+      ", Me = self(),
+       Srv = spawn(FibSrv),
+       Srv ! {fib, 5, Me}, A = receive Ra -> Ra end,
+       Srv ! {fib, 6, Me}, B = receive Rb -> Rb end,
+       Srv ! {fib, 7, Me}, C = receive Rc -> Rc end,
+       Srv ! {fib, 8, Me}, D = receive Rd -> Rd end,
+       Srv ! stop,
+       A + B + C + D"))
+  47)
+
+;; Verify Fib obeys the recurrence — fib(n) = fib(n-1) + fib(n-2).
+(er-fib-test
+  "fib recurrence at n=12"
+  (fib-ev
+    (str
+      er-fib-server-src
+      ", Me = self(),
+       Srv = spawn(FibSrv),
+       Srv ! {fib, 10, Me}, A = receive Ra -> Ra end,
+       Srv ! {fib, 11, Me}, B = receive Rb -> Rb end,
+       Srv ! {fib, 12, Me}, C = receive Rc -> Rc end,
+       Srv ! stop,
+       C - (A + B)"))
+  0)
+
+;; Two clients each get their own answer; main sums the results.
+(er-fib-test
+  "two clients sum"
+  (fib-ev
+    (str
+      er-fib-server-src
+      ", Me = self(),
+       Srv = spawn(FibSrv),
+       Client = fun (N) ->
+         spawn(fun () ->
+           Srv ! {fib, N, self()},
+           receive R -> Me ! {result, R} end
+         end)
+       end,
+       Client(7),
+       Client(9),
+       {result, A} = receive M1 -> M1 end,
+       {result, B} = receive M2 -> M2 end,
+       Srv ! stop,
+       A + B"))
+  47)
+
+;; Trace queries via io-buffer.
+(er-fib-test
+  "trace fib 0..6"
+  (do
+    (er-io-flush!)
+    (fib-ev
+      (str
+        er-fib-server-src
+        ", Me = self(),
+         Srv = spawn(FibSrv),
+         Ask = fun (N) -> Srv ! {fib, N, Me}, receive R -> io:format(\"~p \", [R]) end end,
+         Ask(0), Ask(1), Ask(2), Ask(3), Ask(4), Ask(5), Ask(6),
+         Srv ! stop,
+         done"))
+    (er-io-buffer-content))
+  "0 1 1 2 3 5 8 ")
+
+(define
+  er-fib-test-summary
+  (str "fib " er-fib-test-pass "/" er-fib-test-count))

lib/erlang/tests/programs/ping_pong.sx

@@ -0,0 +1,127 @@
+;; Ping-pong program — two processes exchange N messages, then signal
+;; main via separate `ping_done` / `pong_done` notifications.
+
+(define er-pp-test-count 0)
+(define er-pp-test-pass 0)
+(define er-pp-test-fails (list))
+
+(define
+  er-pp-test
+  (fn
+    (name actual expected)
+    (set! er-pp-test-count (+ er-pp-test-count 1))
+    (if
+      (= actual expected)
+      (set! er-pp-test-pass (+ er-pp-test-pass 1))
+      (append! er-pp-test-fails {:actual actual :expected expected :name name}))))
+
+(define pp-ev erlang-eval-ast)
+
+;; Three rounds of ping-pong, then stop. Main receives ping_done and
+;; pong_done in arrival order (Ping finishes first because Pong exits
+;; only after receiving stop).
+(define
+  er-pp-program
+  "Me = self(),
+   Pong = spawn(fun () ->
+     Loop = fun () ->
+       receive
+         {ping, From} -> From ! pong, Loop();
+         stop -> Me ! pong_done
+       end
+     end,
+     Loop()
+   end),
+   Ping = fun (Target, K) ->
+     if K =:= 0 -> Target ! stop, Me ! ping_done;
+        true -> Target ! {ping, self()}, receive pong -> Ping(Target, K - 1) end
+     end
+   end,
+   spawn(fun () -> Ping(Pong, 3) end),
+   receive ping_done -> ok end,
+   receive pong_done -> both_done end")
+
+(er-pp-test
+  "ping-pong 3 rounds"
+  (get (pp-ev er-pp-program) :name)
+  "both_done")
+
+;; Count exchanges via io-buffer — each pong trip prints "p".
+(er-pp-test
+  "ping-pong 5 rounds trace"
+  (do
+    (er-io-flush!)
+    (pp-ev
+      "Me = self(),
+       Pong = spawn(fun () ->
+         Loop = fun () ->
+           receive
+             {ping, From} -> io:format(\"p\"), From ! pong, Loop();
+             stop -> Me ! pong_done
+           end
+         end,
+         Loop()
+       end),
+       Ping = fun (Target, K) ->
+         if K =:= 0 -> Target ! stop, Me ! ping_done;
+            true -> Target ! {ping, self()}, receive pong -> Ping(Target, K - 1) end
+         end
+       end,
+       spawn(fun () -> Ping(Pong, 5) end),
+       receive ping_done -> ok end,
+       receive pong_done -> ok end")
+    (er-io-buffer-content))
+  "ppppp")
+
+;; Main → Pong directly (no Ping process). Main plays the ping role.
+(er-pp-test
+  "main-as-pinger 4 rounds"
+  (pp-ev
+    "Me = self(),
+     Pong = spawn(fun () ->
+       Loop = fun () ->
+         receive
+           {ping, From} -> From ! pong, Loop();
+           stop -> ok
+         end
+       end,
+       Loop()
+     end),
+     Go = fun (K) ->
+       if K =:= 0 -> Pong ! stop, K;
+          true -> Pong ! {ping, Me}, receive pong -> Go(K - 1) end
+       end
+     end,
+     Go(4)")
+  0)
+
+;; Ensure the processes really interleave — inject an id into each
+;; ping and check we get them all back via trace (the order is
+;; deterministic under our sync scheduler).
+(er-pp-test
+  "ids round-trip"
+  (do
+    (er-io-flush!)
+    (pp-ev
+      "Me = self(),
+       Pong = spawn(fun () ->
+         Loop = fun () ->
+           receive
+             {ping, From, Id} -> From ! {pong, Id}, Loop();
+             stop -> ok
+           end
+         end,
+         Loop()
+       end),
+       Go = fun (K) ->
+         if K =:= 0 -> Pong ! stop, done;
+            true -> Pong ! {ping, Me, K}, receive {pong, RId} -> io:format(\"~p \", [RId]), Go(K - 1) end
+         end
+       end,
+       Go(4)")
+    (er-io-buffer-content))
+  "4 3 2 1 ")
+
+(define
+  er-pp-test-summary
+  (str "ping-pong " er-pp-test-pass "/" er-pp-test-count))

lib/erlang/tests/programs/ring.sx

@@ -0,0 +1,132 @@
+;; Ring program — N processes in a ring, token passes M times.
+;;
+;; Each process waits for {setup, Next} so main can tie the knot
+;; (can't reference a pid before spawning it). Once wired, main
+;; injects the first token; each process forwards decrementing K
+;; until it hits 0, at which point it signals `done` to main.
+
+(define er-ring-test-count 0)
+(define er-ring-test-pass 0)
+(define er-ring-test-fails (list))
+
+(define
+  er-ring-test
+  (fn
+    (name actual expected)
+    (set! er-ring-test-count (+ er-ring-test-count 1))
+    (if
+      (= actual expected)
+      (set! er-ring-test-pass (+ er-ring-test-pass 1))
+      (append! er-ring-test-fails {:actual actual :expected expected :name name}))))
+
+(define ring-ev erlang-eval-ast)
+
+(define
+  er-ring-program-3-6
+  "Me = self(),
+   Spawner = fun () ->
+     receive {setup, Next} ->
+       Loop = fun () ->
+         receive
+           {token, 0, Parent} -> Parent ! done;
+           {token, K, Parent} -> Next ! {token, K-1, Parent}, Loop()
+         end
+       end,
+       Loop()
+     end
+   end,
+   P1 = spawn(Spawner),
+   P2 = spawn(Spawner),
+   P3 = spawn(Spawner),
+   P1 ! {setup, P2},
+   P2 ! {setup, P3},
+   P3 ! {setup, P1},
+   P1 ! {token, 5, Me},
+   receive done -> finished end")
+
+(er-ring-test
+  "ring N=3 M=6"
+  (get (ring-ev er-ring-program-3-6) :name)
+  "finished")
+
+;; Two-node ring — token bounces twice between P1 and P2.
+(er-ring-test
+  "ring N=2 M=4"
+  (get (ring-ev
+    "Me = self(),
+     Spawner = fun () ->
+       receive {setup, Next} ->
+         Loop = fun () ->
+           receive
+             {token, 0, Parent} -> Parent ! done;
+             {token, K, Parent} -> Next ! {token, K-1, Parent}, Loop()
+           end
+         end,
+         Loop()
+       end
+     end,
+     P1 = spawn(Spawner),
+     P2 = spawn(Spawner),
+     P1 ! {setup, P2},
+     P2 ! {setup, P1},
+     P1 ! {token, 3, Me},
+     receive done -> done end") :name)
+  "done")
+
+;; Single-node "ring" — P sends to itself M times.
+(er-ring-test
+  "ring N=1 M=5"
+  (get (ring-ev
+    "Me = self(),
+     Spawner = fun () ->
+       receive {setup, Next} ->
+         Loop = fun () ->
+           receive
+             {token, 0, Parent} -> Parent ! finished_loop;
+             {token, K, Parent} -> Next ! {token, K-1, Parent}, Loop()
+           end
+         end,
+         Loop()
+       end
+     end,
+     P = spawn(Spawner),
+     P ! {setup, P},
+     P ! {token, 4, Me},
+     receive finished_loop -> ok end") :name)
+  "ok")
+
+;; Confirm the token really went around — count hops via io-buffer.
+(er-ring-test
+  "ring N=3 M=9 hop count"
+  (do
+    (er-io-flush!)
+    (ring-ev
+      "Me = self(),
+       Spawner = fun () ->
+         receive {setup, Next} ->
+           Loop = fun () ->
+             receive
+               {token, 0, Parent} -> Parent ! done;
+               {token, K, Parent} ->
+                 io:format(\"~p \", [K]),
+                 Next ! {token, K-1, Parent},
+                 Loop()
+             end
+           end,
+           Loop()
+         end
+       end,
+       P1 = spawn(Spawner),
+       P2 = spawn(Spawner),
+       P3 = spawn(Spawner),
+       P1 ! {setup, P2},
+       P2 ! {setup, P3},
+       P3 ! {setup, P1},
+       P1 ! {token, 8, Me},
+       receive done -> done end")
+    (er-io-buffer-content))
+  "8 7 6 5 4 3 2 1 ")
+
+(define
+  er-ring-test-summary
+  (str "ring " er-ring-test-pass "/" er-ring-test-count))

lib/erlang/tests/runtime.sx

@@ -0,0 +1,139 @@
+;; Erlang runtime tests — scheduler + process-record primitives.
+
+(define er-rt-test-count 0)
+(define er-rt-test-pass 0)
+(define er-rt-test-fails (list))
+
+(define
+  er-rt-test
+  (fn
+    (name actual expected)
+    (set! er-rt-test-count (+ er-rt-test-count 1))
+    (if
+      (= actual expected)
+      (set! er-rt-test-pass (+ er-rt-test-pass 1))
+      (append! er-rt-test-fails {:actual actual :expected expected :name name}))))
+
+;; ── queue ─────────────────────────────────────────────────────────
+(er-rt-test "queue empty len" (er-q-len (er-q-new)) 0)
+(er-rt-test "queue empty?" (er-q-empty? (er-q-new)) true)
+
+(define q1 (er-q-new))
+(er-q-push! q1 "a")
+(er-q-push! q1 "b")
+(er-q-push! q1 "c")
+(er-rt-test "queue push len" (er-q-len q1) 3)
+(er-rt-test "queue empty? after push" (er-q-empty? q1) false)
+(er-rt-test "queue peek" (er-q-peek q1) "a")
+(er-rt-test "queue pop 1" (er-q-pop! q1) "a")
+(er-rt-test "queue pop 2" (er-q-pop! q1) "b")
+(er-rt-test "queue len after pops" (er-q-len q1) 1)
+(er-rt-test "queue pop 3" (er-q-pop! q1) "c")
+(er-rt-test "queue empty again" (er-q-empty? q1) true)
+(er-rt-test "queue pop empty" (er-q-pop! q1) nil)
+
+;; Queue FIFO under interleaved push/pop
+(define q2 (er-q-new))
+(er-q-push! q2 1)
+(er-q-push! q2 2)
+(er-q-pop! q2)
+(er-q-push! q2 3)
+(er-rt-test "queue interleave peek" (er-q-peek q2) 2)
+(er-rt-test "queue to-list" (er-q-to-list q2) (list 2 3))
+
+;; ── scheduler init ─────────────────────────────────────────────
+(er-sched-init!)
+(er-rt-test "sched process count 0" (er-sched-process-count) 0)
+(er-rt-test "sched runnable count 0" (er-sched-runnable-count) 0)
+(er-rt-test "sched current nil" (er-sched-current-pid) nil)
+
+;; ── pid allocation ─────────────────────────────────────────────
+(define pa (er-pid-new!))
+(define pb (er-pid-new!))
+(er-rt-test "pid tag" (get pa :tag) "pid")
+(er-rt-test "pid ids distinct" (= (er-pid-id pa) (er-pid-id pb)) false)
+(er-rt-test "pid? true" (er-pid? pa) true)
+(er-rt-test "pid? false" (er-pid? 42) false)
+(er-rt-test
+  "pid-equal same"
+  (er-pid-equal? pa (er-mk-pid (er-pid-id pa)))
+  true)
+(er-rt-test "pid-equal diff" (er-pid-equal? pa pb) false)
+
+;; ── process lifecycle ──────────────────────────────────────────
+(er-sched-init!)
+(define p1 (er-proc-new! {}))
+(define p2 (er-proc-new! {}))
+(er-rt-test "proc count 2" (er-sched-process-count) 2)
+(er-rt-test "runnable count 2" (er-sched-runnable-count) 2)
+(er-rt-test
+  "proc state runnable"
+  (er-proc-field (get p1 :pid) :state)
+  "runnable")
+(er-rt-test
+  "proc mailbox empty"
+  (er-proc-mailbox-size (get p1 :pid))
+  0)
+(er-rt-test
+  "proc lookup"
+  (er-pid-equal? (get (er-proc-get (get p1 :pid)) :pid) (get p1 :pid))
+  true)
+(er-rt-test "proc exists" (er-proc-exists? (get p1 :pid)) true)
+(er-rt-test
+  "proc no-such-pid"
+  (er-proc-exists? (er-mk-pid 9999))
+  false)
+
+;; runnable queue dequeue order
+(er-rt-test
+  "dequeue first"
+  (er-pid-equal? (er-sched-next-runnable!) (get p1 :pid))
+  true)
+(er-rt-test
+  "dequeue second"
+  (er-pid-equal? (er-sched-next-runnable!) (get p2 :pid))
+  true)
+(er-rt-test "dequeue empty" (er-sched-next-runnable!) nil)
+
+;; current-pid get/set
+(er-sched-set-current! (get p1 :pid))
+(er-rt-test
+  "current pid set"
+  (er-pid-equal? (er-sched-current-pid) (get p1 :pid))
+  true)
+
+;; ── mailbox push ──────────────────────────────────────────────
+(er-proc-mailbox-push! (get p1 :pid) {:tag "atom" :name "ping"})
+(er-proc-mailbox-push! (get p1 :pid) 42)
+(er-rt-test "mailbox size 2" (er-proc-mailbox-size (get p1 :pid)) 2)
+
+;; ── field update ──────────────────────────────────────────────
+(er-proc-set! (get p1 :pid) :state "waiting")
+(er-rt-test
+  "proc state waiting"
+  (er-proc-field (get p1 :pid) :state)
+  "waiting")
+(er-proc-set! (get p1 :pid) :trap-exit true)
+(er-rt-test
+  "proc trap-exit"
+  (er-proc-field (get p1 :pid) :trap-exit)
+  true)
+
+;; ── fresh scheduler ends in clean state ───────────────────────
+(er-sched-init!)
+(er-rt-test
+  "sched init resets count"
+  (er-sched-process-count)
+  0)
+(er-rt-test
+  "sched init resets queue"
+  (er-sched-runnable-count)
+  0)
+(er-rt-test
+  "sched init resets current"
+  (er-sched-current-pid)
+  nil)
+
+(define
+  er-rt-test-summary
+  (str "runtime " er-rt-test-pass "/" er-rt-test-count))