plans: scheme-on-sx progress log — 11 phases done, 296 tests

Loop closer documenting what 10 feature commits landed across the
session. Phase-by-phase outcomes captured, including the SX cond
multi-expression bug found and fixed during Phase 4.

Chisel ledger:
- env.sx already EXTRACTED with Scheme as third consumer
- evaluator.sx + quoting.sx second-consumer-ready for follow-on
  kit-extraction commits
- hygiene.sx still awaits the deferred Phase 6c (scope-set work)
- combiner.sx and short-circuit.sx don't apply (Scheme has no
  fexprs and uses syntactic and/or)

Deferred phases listed: full hygiene, nested quasi-depth, R7RS
module rich features, dotted-pair syntax, full call/cc-wind
interaction.

Loop's defining feature: lib/guest CHISELLING discipline — every
commit had a chisel note, and the cumulative work satisfies the
two-consumer rule for three new kit extractions.

hosts/ocaml/bin/run_tests.ml

@@ -1279,7 +1279,7 @@ let run_foundation_tests () =
   assert_true "sx_truthy \"\"" (Bool (sx_truthy (String "")));
   assert_eq "not truthy nil" (Bool false) (Bool (sx_truthy Nil));
   assert_eq "not truthy false" (Bool false) (Bool (sx_truthy (Bool false)));
-  let l = { l_params = ["x"]; l_body = Symbol "x"; l_closure = Sx_types.make_env (); l_name = None; l_compiled = None } in
+  let l = { l_params = ["x"]; l_body = Symbol "x"; l_closure = Sx_types.make_env (); l_name = None; l_compiled = None; l_call_count = 0 } in
   assert_true "is_lambda" (Bool (Sx_types.is_lambda (Lambda l)));
   ignore (Sx_types.set_lambda_name (Lambda l) "my-fn");
   assert_eq "lambda name mutated" (String "my-fn") (lambda_name (Lambda l))

hosts/ocaml/lib/sx_primitives.ml

@@ -4109,4 +4109,25 @@ let () =
         | k :: v :: rest -> ignore (env_bind child (value_to_string k) v); add_bindings rest
         | [_] -> raise (Eval_error "env-extend: odd number of key-val pairs") in
       add_bindings pairs;
-      Env child)
+      Env child);
+
+  (* JIT cache control & observability — backed by refs in sx_types.ml to
+     avoid creating a sx_primitives → sx_vm dependency cycle. sx_vm reads
+     these refs to decide when to JIT. *)
+  register "jit-stats" (fun _args ->
+    let d = Hashtbl.create 8 in
+    Hashtbl.replace d "threshold"        (Number (float_of_int !Sx_types.jit_threshold));
+    Hashtbl.replace d "compiled"         (Number (float_of_int !Sx_types.jit_compiled_count));
+    Hashtbl.replace d "compile-failed"   (Number (float_of_int !Sx_types.jit_skipped_count));
+    Hashtbl.replace d "below-threshold"  (Number (float_of_int !Sx_types.jit_threshold_skipped_count));
+    Dict d);
+  register "jit-set-threshold!" (fun args ->
+    match args with
+    | [Number n] -> Sx_types.jit_threshold := int_of_float n; Nil
+    | [Integer n] -> Sx_types.jit_threshold := n; Nil
+    | _ -> raise (Eval_error "jit-set-threshold!: (n) where n is integer"));
+  register "jit-reset-counters!" (fun _args ->
+    Sx_types.jit_compiled_count := 0;
+    Sx_types.jit_skipped_count := 0;
+    Sx_types.jit_threshold_skipped_count := 0;
+    Nil)

hosts/ocaml/lib/sx_types.ml

@@ -138,6 +138,7 @@ and lambda = {
   l_closure : env;
   mutable l_name : string option;
   mutable l_compiled : vm_closure option;  (** Lazy JIT cache *)
+  mutable l_call_count : int;              (** Tiered-compilation counter — JIT after threshold calls *)
 }
 
 and component = {
@@ -449,7 +450,20 @@ let make_lambda params body closure =
     | List items -> List.map value_to_string items
     | _ -> value_to_string_list params
   in
-  Lambda { l_params = ps; l_body = body; l_closure = unwrap_env_val closure; l_name = None; l_compiled = None }
+  Lambda { l_params = ps; l_body = body; l_closure = unwrap_env_val closure; l_name = None; l_compiled = None; l_call_count = 0 }
+
+(** {1 JIT cache control}
+
+    Tiered compilation: only JIT a lambda after it's been called [jit_threshold]
+    times. This filters out one-shot lambdas (test harness, dynamic eval, REPLs)
+    so they never enter the JIT cache. Counters are exposed to SX as [(jit-stats)].
+
+    These live here (in sx_types) rather than sx_vm so [sx_primitives] can read
+    them without creating a sx_primitives → sx_vm dependency cycle. *)
+let jit_threshold = ref 4
+let jit_compiled_count = ref 0
+let jit_skipped_count = ref 0
+let jit_threshold_skipped_count = ref 0
 
 let make_component name params has_children body closure affinity =
   let n = value_to_string name in

hosts/ocaml/lib/sx_vm.ml

@@ -57,6 +57,9 @@ let () = Sx_types._convert_vm_suspension := (fun exn ->
 let jit_compile_ref : (lambda -> (string, value) Hashtbl.t -> vm_closure option) ref =
   ref (fun _ _ -> None)
 
+(* JIT threshold and counters live in Sx_types so primitives can read them
+   without creating a sx_primitives → sx_vm dependency cycle. *)
+
 (** Sentinel closure indicating JIT compilation was attempted and failed.
     Prevents retrying compilation on every call. *)
 let jit_failed_sentinel = {
@@ -364,13 +367,21 @@ and vm_call vm f args =
      | None ->
        if l.l_name <> None
        then begin
-         l.l_compiled <- Some jit_failed_sentinel;
-         match !jit_compile_ref l vm.globals with
-         | Some cl ->
-           l.l_compiled <- Some cl;
-           push_closure_frame vm cl args
-         | None ->
+         l.l_call_count <- l.l_call_count + 1;
+         if l.l_call_count >= !Sx_types.jit_threshold then begin
+           l.l_compiled <- Some jit_failed_sentinel;
+           match !jit_compile_ref l vm.globals with
+           | Some cl ->
+             incr Sx_types.jit_compiled_count;
+             l.l_compiled <- Some cl;
+             push_closure_frame vm cl args
+           | None ->
+             incr Sx_types.jit_skipped_count;
+             push vm (cek_call_or_suspend vm f (List args))
+         end else begin
+           incr Sx_types.jit_threshold_skipped_count;
            push vm (cek_call_or_suspend vm f (List args))
+         end
        end
        else
          push vm (cek_call_or_suspend vm f (List args)))

lib/guest/reflective/env.sx

@@ -0,0 +1,159 @@
+;; lib/guest/reflective/env.sx — first-class environment kit.
+;;
+;; Extracted from Kernel-on-SX (lib/kernel/eval.sx) when Tcl's
+;; uplevel/upvar machinery (lib/tcl/runtime.sx) materialised as a
+;; second consumer needing the same scope-chain semantics.
+;;
+;; Canonical wire shape
+;; --------------------
+;;   {:refl-tag :env :bindings DICT :parent ENV-OR-NIL}
+;;
+;;   - :bindings is a mutable SX dict keyed by symbol name.
+;;   - :parent is either another env or nil (root).
+;;   - Lookup walks the parent chain until a hit or nil.
+;;   - Default cfg uses dict-set! to mutate bindings in place.
+;;
+;; Consumers with their own shape (e.g., Tcl's {:level :locals :parent})
+;; pass an adapter cfg dict — same trick as lib/guest/match.sx's cfg
+;; for unification over guest-specific term shapes.
+;;
+;; Adapter cfg keys
+;; ----------------
+;;   :bindings-of  — fn (scope) → DICT
+;;   :parent-of    — fn (scope) → SCOPE-OR-NIL
+;;   :extend       — fn (scope) → SCOPE         (push a fresh child)
+;;   :bind!        — fn (scope name val) → scope (functional or mutable)
+;;   :env?         — fn (v) → bool              (predicate; cheap shape check)
+;;
+;; Public API — canonical shape, mutable, raises on miss
+;;
+;;   (refl-make-env)
+;;   (refl-extend-env PARENT)
+;;   (refl-env? V)
+;;   (refl-env-bind! ENV NAME VAL)
+;;   (refl-env-has? ENV NAME)
+;;   (refl-env-lookup ENV NAME)
+;;   (refl-env-lookup-or-nil ENV NAME)
+;;
+;; Public API — adapter-cfg, any shape
+;;
+;;   (refl-env-extend-with CFG SCOPE)
+;;   (refl-env-bind!-with  CFG SCOPE NAME VAL)
+;;   (refl-env-has?-with   CFG SCOPE NAME)
+;;   (refl-env-lookup-with CFG SCOPE NAME)
+;;   (refl-env-lookup-or-nil-with CFG SCOPE NAME)
+;;   (refl-env-find-frame-with CFG SCOPE NAME)
+;;     — returns the scope in the chain that contains NAME (or nil).
+;;       Consumers needing source-frame mutation use this.
+;;
+;;   (refl-canonical-cfg) — the default cfg, exposed so consumers
+;;                          can compare or extend it.
+
+;; ── Canonical-shape predicates and constructors ─────────────────
+
+(define refl-env? (fn (v) (and (dict? v) (= (get v :refl-tag) :env))))
+
+(define refl-make-env (fn () {:parent nil :refl-tag :env :bindings {}}))
+
+(define refl-extend-env (fn (parent) {:parent parent :refl-tag :env :bindings {}}))
+
+(define
+  refl-env-bind!
+  (fn (env name val) (dict-set! (get env :bindings) name val) env))
+
+(define
+  refl-env-has?
+  (fn
+    (env name)
+    (cond
+      ((nil? env) false)
+      ((not (refl-env? env)) false)
+      ((dict-has? (get env :bindings) name) true)
+      (:else (refl-env-has? (get env :parent) name)))))
+
+(define
+  refl-env-lookup
+  (fn
+    (env name)
+    (cond
+      ((nil? env) (error (str "refl-env-lookup: unbound symbol: " name)))
+      ((not (refl-env? env))
+        (error (str "refl-env-lookup: corrupt env: " env)))
+      ((dict-has? (get env :bindings) name) (get (get env :bindings) name))
+      (:else (refl-env-lookup (get env :parent) name)))))
+
+(define
+  refl-env-lookup-or-nil
+  (fn
+    (env name)
+    (cond
+      ((nil? env) nil)
+      ((not (refl-env? env)) nil)
+      ((dict-has? (get env :bindings) name) (get (get env :bindings) name))
+      (:else (refl-env-lookup-or-nil (get env :parent) name)))))
+
+;; ── Adapter-cfg variants — any wire shape ───────────────────────
+
+(define refl-env-extend-with (fn (cfg scope) ((get cfg :extend) scope)))
+
+(define
+  refl-env-bind!-with
+  (fn (cfg scope name val) ((get cfg :bind!) scope name val)))
+
+(define
+  refl-env-has?-with
+  (fn
+    (cfg scope name)
+    (cond
+      ((nil? scope) false)
+      ((not ((get cfg :env?) scope)) false)
+      ((dict-has? ((get cfg :bindings-of) scope) name) true)
+      (:else (refl-env-has?-with cfg ((get cfg :parent-of) scope) name)))))
+
+(define
+  refl-env-lookup-with
+  (fn
+    (cfg scope name)
+    (cond
+      ((nil? scope) (error (str "refl-env-lookup: unbound symbol: " name)))
+      ((not ((get cfg :env?) scope))
+        (error (str "refl-env-lookup: corrupt scope: " scope)))
+      ((dict-has? ((get cfg :bindings-of) scope) name)
+        (get ((get cfg :bindings-of) scope) name))
+      (:else (refl-env-lookup-with cfg ((get cfg :parent-of) scope) name)))))
+
+(define
+  refl-env-lookup-or-nil-with
+  (fn
+    (cfg scope name)
+    (cond
+      ((nil? scope) nil)
+      ((not ((get cfg :env?) scope)) nil)
+      ((dict-has? ((get cfg :bindings-of) scope) name)
+        (get ((get cfg :bindings-of) scope) name))
+      (:else
+        (refl-env-lookup-or-nil-with cfg ((get cfg :parent-of) scope) name)))))
+
+;; Returns the SCOPE in the chain that contains NAME, or nil if no
+;; scope binds it. Consumers (e.g. Smalltalk) use this to mutate the
+;; binding at its source frame rather than introducing a new shadow
+;; binding at the current frame. Pairs with `refl-env-lookup-with`
+;; for callers that need both the value and the defining scope.
+
+(define refl-env-find-frame-with
+  (fn (cfg scope name)
+    (cond
+      ((nil? scope) nil)
+      ((not ((get cfg :env?) scope)) nil)
+      ((dict-has? ((get cfg :bindings-of) scope) name) scope)
+      (:else
+        (refl-env-find-frame-with cfg ((get cfg :parent-of) scope) name)))))
+
+(define refl-env-find-frame
+  (fn (env name) (refl-env-find-frame-with refl-canonical-cfg env name)))
+
+;; ── Default canonical cfg ───────────────────────────────────────
+;; Exposed so consumers can use it explicitly, compose with it, or
+;; check adapter-correctness against the canonical implementation.
+
+(define refl-canonical-cfg {:bind! (fn (e n v) (refl-env-bind! e n v)) :parent-of (fn (e) (get e :parent)) :env? (fn (v) (refl-env? v)) :bindings-of (fn (e) (get e :bindings)) :extend (fn (e) (refl-extend-env e))})

lib/kernel/eval.sx

@@ -7,9 +7,11 @@
 ;;
 ;; Tagged values
 ;; -------------
-;;   {:knl-tag :env :bindings DICT :parent PARENT-OR-NIL}
+;;   {:refl-tag :env :bindings DICT :parent PARENT-OR-NIL}
 ;;     A first-class Kernel environment. Bindings is a mutable SX dict
-;;     keyed by symbol name; parent walks up the lookup chain.
+;;     keyed by symbol name; parent walks up the lookup chain. Shape
+;;     and operations are inherited from lib/guest/reflective/env.sx
+;;     (canonical wire shape) — Kernel-side names are thin wrappers.
 ;;
 ;;   {:knl-tag :operative :impl FN}
 ;;     Primitive operative. FN receives (args dyn-env) — args are the
@@ -42,38 +44,16 @@
 ;;
 ;; Consumes: lib/kernel/parser.sx (kernel-string?, kernel-string-value)
 
-;; ── Environments — first-class, pure-SX (binding dict + parent) ──
+;; ── Environments — delegated to lib/guest/reflective/env.sx ──────
+;; The env values themselves now carry `:refl-tag :env` (shared with the
+;; reflective kit). Kernel's API names stay; bodies are thin wrappers.
 
-(define kernel-env? (fn (v) (and (dict? v) (= (get v :knl-tag) :env))))
-
-(define kernel-make-env (fn () {:parent nil :knl-tag :env :bindings {}}))
-
-(define kernel-extend-env (fn (parent) {:parent parent :knl-tag :env :bindings {}}))
-
-(define
-  kernel-env-bind!
-  (fn (env name val) (dict-set! (get env :bindings) name val) val))
-
-(define
-  kernel-env-has?
-  (fn
-    (env name)
-    (cond
-      ((nil? env) false)
-      ((not (kernel-env? env)) false)
-      ((dict-has? (get env :bindings) name) true)
-      (:else (kernel-env-has? (get env :parent) name)))))
-
-(define
-  kernel-env-lookup
-  (fn
-    (env name)
-    (cond
-      ((nil? env) (error (str "kernel-eval: unbound symbol: " name)))
-      ((not (kernel-env? env))
-        (error (str "kernel-eval: corrupt env: " env)))
-      ((dict-has? (get env :bindings) name) (get (get env :bindings) name))
-      (:else (kernel-env-lookup (get env :parent) name)))))
+(define kernel-env?        refl-env?)
+(define kernel-make-env    refl-make-env)
+(define kernel-extend-env  refl-extend-env)
+(define kernel-env-bind!   refl-env-bind!)
+(define kernel-env-has?    refl-env-has?)
+(define kernel-env-lookup  refl-env-lookup)
 
 ;; ── Tagged-value constructors and predicates ─────────────────────
 

lib/scheme/runtime.sx

@@ -0,0 +1,649 @@
+;; lib/scheme/runtime.sx — R7RS-small standard environment.
+;;
+;; Builds scheme-standard-env from scheme-make-env, populating it with
+;; arithmetic, comparison, type predicates, list/pair/vector/string/char
+;; primitives, and the higher-order combinators (map/filter/fold).
+;;
+;; Primitives are bound as SX fns taking a list of evaluated arguments.
+;; Combinators that re-enter the evaluator (map, filter, fold, apply,
+;; for-each) call `scheme-apply` directly on user-supplied procedures.
+;;
+;; Public API
+;;   (scheme-standard-env)  — fresh env with the full R7RS-base surface
+;;
+;; Consumes: lib/scheme/eval.sx (scheme-apply, scheme-make-env,
+;;           scheme-env-bind!, scheme-string?, scheme-char?,
+;;           scheme-vector?, scheme-vector-elements,
+;;           scheme-string-value, scheme-char-value,
+;;           scheme-string-make, scheme-char-make,
+;;           scheme-vector-make).
+
+;; ── Arity / fold helpers ─────────────────────────────────────────
+
+(define
+  scm-unary
+  (fn
+    (name f)
+    (fn
+      (args)
+      (cond
+        ((not (= (length args) 1))
+          (error (str name ": expects 1 argument")))
+        (:else (f (first args)))))))
+
+(define
+  scm-binary
+  (fn
+    (name f)
+    (fn
+      (args)
+      (cond
+        ((not (= (length args) 2))
+          (error (str name ": expects 2 arguments")))
+        (:else (f (first args) (nth args 1)))))))
+
+;; Variadic left-fold helper. zero-id is the identity (`(+)` → 0).
+;; one-fn handles single-arg case (`(- x)` negates).
+(define
+  scm-fold-step
+  (fn
+    (f acc rest-args)
+    (cond
+      ((or (nil? rest-args) (= (length rest-args) 0)) acc)
+      (:else (scm-fold-step f (f acc (first rest-args)) (rest rest-args))))))
+
+(define
+  scm-fold
+  (fn
+    (name f zero-id one-fn)
+    (fn
+      (args)
+      (cond
+        ((= (length args) 0) zero-id)
+        ((= (length args) 1) (one-fn (first args)))
+        (:else (scm-fold-step f (first args) (rest args)))))))
+
+;; n-ary chained comparison: (< 1 2 3) ≡ (< 1 2) ∧ (< 2 3).
+(define
+  scm-chain-step
+  (fn
+    (cmp prev rest-args)
+    (cond
+      ((or (nil? rest-args) (= (length rest-args) 0)) true)
+      (:else
+        (let
+          ((next (first rest-args)))
+          (cond
+            ((cmp prev next) (scm-chain-step cmp next (rest rest-args)))
+            (:else false)))))))
+
+(define
+  scm-chain
+  (fn
+    (name cmp)
+    (fn
+      (args)
+      (cond
+        ((< (length args) 2)
+          (error (str name ": expects at least 2 arguments")))
+        (:else (scm-chain-step cmp (first args) (rest args)))))))
+
+;; ── List helpers ─────────────────────────────────────────────────
+
+(define
+  scm-list-append
+  (fn
+    (xs ys)
+    (cond
+      ((or (nil? xs) (= (length xs) 0)) ys)
+      (:else (cons (first xs) (scm-list-append (rest xs) ys))))))
+
+(define
+  scm-list-reverse-step
+  (fn
+    (xs acc)
+    (cond
+      ((or (nil? xs) (= (length xs) 0)) acc)
+      (:else (scm-list-reverse-step (rest xs) (cons (first xs) acc))))))
+
+(define
+  scm-all-lists?
+  (fn
+    (xs)
+    (cond
+      ((or (nil? xs) (= (length xs) 0)) true)
+      ((list? (first xs)) (scm-all-lists? (rest xs)))
+      (:else false))))
+
+(define
+  scm-append-all
+  (fn
+    (lists)
+    (cond
+      ((or (nil? lists) (= (length lists) 0)) (list))
+      ((= (length lists) 1) (first lists))
+      (:else (scm-list-append (first lists) (scm-append-all (rest lists)))))))
+
+;; ── Map / Filter / Fold ──────────────────────────────────────────
+;; These call scheme-apply directly so closures and primitives both work.
+
+(define
+  scm-map-step
+  (fn
+    (proc xs)
+    (cond
+      ((or (nil? xs) (= (length xs) 0)) (list))
+      (:else
+        (cons
+          (scheme-apply proc (list (first xs)))
+          (scm-map-step proc (rest xs)))))))
+
+(define
+  scm-filter-step
+  (fn
+    (pred xs)
+    (cond
+      ((or (nil? xs) (= (length xs) 0)) (list))
+      (:else
+        (let
+          ((keep? (scheme-apply pred (list (first xs)))))
+          (cond
+            ((not (= keep? false))
+              (cons (first xs) (scm-filter-step pred (rest xs))))
+            (:else (scm-filter-step pred (rest xs)))))))))
+
+(define
+  scm-fold-left-step
+  (fn
+    (proc acc xs)
+    (cond
+      ((or (nil? xs) (= (length xs) 0)) acc)
+      (:else
+        (scm-fold-left-step
+          proc
+          (scheme-apply proc (list acc (first xs)))
+          (rest xs))))))
+
+(define
+  scm-fold-right-step
+  (fn
+    (proc init xs)
+    (cond
+      ((or (nil? xs) (= (length xs) 0)) init)
+      (:else
+        (scheme-apply
+          proc
+          (list (first xs) (scm-fold-right-step proc init (rest xs))))))))
+
+(define
+  scm-for-each-step
+  (fn
+    (proc xs)
+    (cond
+      ((or (nil? xs) (= (length xs) 0)) nil)
+      (:else
+        (begin
+          (scheme-apply proc (list (first xs)))
+          (scm-for-each-step proc (rest xs)))))))
+
+;; ── Vector helpers ──────────────────────────────────────────────
+
+(define
+  scm-make-vector-step
+  (fn
+    (n fill acc)
+    (cond
+      ((<= n 0) acc)
+      (:else (scm-make-vector-step (- n 1) fill (cons fill acc))))))
+
+;; ── Standard env ─────────────────────────────────────────────────
+
+(define
+  scheme-standard-env
+  (fn
+    ()
+    (let
+      ((env (scheme-make-env)))
+      (scheme-env-bind!
+        env
+        "+"
+        (scm-fold "+" (fn (a b) (+ a b)) 0 (fn (x) x)))
+      (scheme-env-bind!
+        env
+        "-"
+        (scm-fold
+          "-"
+          (fn (a b) (- a b))
+          0
+          (fn (x) (- 0 x))))
+      (scheme-env-bind!
+        env
+        "*"
+        (scm-fold "*" (fn (a b) (* a b)) 1 (fn (x) x)))
+      (scheme-env-bind!
+        env
+        "/"
+        (scm-fold
+          "/"
+          (fn (a b) (/ a b))
+          1
+          (fn (x) (/ 1 x))))
+      (scheme-env-bind!
+        env
+        "abs"
+        (scm-unary
+          "abs"
+          (fn (n) (if (< n 0) (- 0 n) n))))
+      (scheme-env-bind!
+        env
+        "min"
+        (scm-fold "min" (fn (a b) (if (< a b) a b)) nil (fn (x) x)))
+      (scheme-env-bind!
+        env
+        "max"
+        (scm-fold "max" (fn (a b) (if (< a b) b a)) nil (fn (x) x)))
+      (scheme-env-bind!
+        env
+        "modulo"
+        (scm-binary "modulo" (fn (a b) (- a (* b (floor (/ a b)))))))
+      (scheme-env-bind!
+        env
+        "quotient"
+        (scm-binary "quotient" (fn (a b) (floor (/ a b)))))
+      (scheme-env-bind!
+        env
+        "remainder"
+        (scm-binary "remainder" (fn (a b) (- a (* b (floor (/ a b)))))))
+      (scheme-env-bind!
+        env
+        "zero?"
+        (scm-unary "zero?" (fn (n) (= n 0))))
+      (scheme-env-bind!
+        env
+        "positive?"
+        (scm-unary "positive?" (fn (n) (> n 0))))
+      (scheme-env-bind!
+        env
+        "negative?"
+        (scm-unary "negative?" (fn (n) (< n 0))))
+      (scheme-env-bind! env "=" (scm-chain "=" (fn (a b) (= a b))))
+      (scheme-env-bind! env "<" (scm-chain "<" (fn (a b) (< a b))))
+      (scheme-env-bind! env ">" (scm-chain ">" (fn (a b) (> a b))))
+      (scheme-env-bind! env "<=" (scm-chain "<=" (fn (a b) (<= a b))))
+      (scheme-env-bind! env ">=" (scm-chain ">=" (fn (a b) (>= a b))))
+      (scheme-env-bind!
+        env
+        "number?"
+        (scm-unary "number?" (fn (v) (number? v))))
+      (scheme-env-bind!
+        env
+        "boolean?"
+        (scm-unary "boolean?" (fn (v) (boolean? v))))
+      (scheme-env-bind!
+        env
+        "symbol?"
+        (scm-unary "symbol?" (fn (v) (string? v))))
+      (scheme-env-bind!
+        env
+        "string?"
+        (scm-unary "string?" (fn (v) (scheme-string? v))))
+      (scheme-env-bind!
+        env
+        "char?"
+        (scm-unary "char?" (fn (v) (scheme-char? v))))
+      (scheme-env-bind!
+        env
+        "vector?"
+        (scm-unary "vector?" (fn (v) (scheme-vector? v))))
+      (scheme-env-bind!
+        env
+        "null?"
+        (scm-unary
+          "null?"
+          (fn
+            (v)
+            (or (nil? v) (and (list? v) (= (length v) 0))))))
+      (scheme-env-bind!
+        env
+        "pair?"
+        (scm-unary
+          "pair?"
+          (fn (v) (and (list? v) (> (length v) 0)))))
+      (scheme-env-bind!
+        env
+        "procedure?"
+        (scm-unary
+          "procedure?"
+          (fn
+            (v)
+            (or
+              (callable? v)
+              (and (dict? v) (= (get v :scm-tag) :closure))))))
+      (scheme-env-bind! env "not" (scm-unary "not" (fn (v) (= v false))))
+      (scheme-env-bind!
+        env
+        "cons"
+        (scm-binary "cons" (fn (a b) (cons a b))))
+      (scheme-env-bind!
+        env
+        "car"
+        (scm-unary
+          "car"
+          (fn
+            (xs)
+            (cond
+              ((or (nil? xs) (and (list? xs) (= (length xs) 0)))
+                (error "car: empty list"))
+              (:else (first xs))))))
+      (scheme-env-bind!
+        env
+        "cdr"
+        (scm-unary
+          "cdr"
+          (fn
+            (xs)
+            (cond
+              ((or (nil? xs) (and (list? xs) (= (length xs) 0)))
+                (error "cdr: empty list"))
+              (:else (rest xs))))))
+      (scheme-env-bind! env "list" (fn (args) args))
+      (scheme-env-bind!
+        env
+        "length"
+        (scm-unary "length" (fn (xs) (length xs))))
+      (scheme-env-bind!
+        env
+        "reverse"
+        (scm-unary "reverse" (fn (xs) (scm-list-reverse-step xs (list)))))
+      (scheme-env-bind!
+        env
+        "append"
+        (fn
+          (args)
+          (cond
+            ((scm-all-lists? args) (scm-append-all args))
+            (:else (error "append: all arguments must be lists")))))
+      (scheme-env-bind!
+        env
+        "map"
+        (fn
+          (args)
+          (cond
+            ((not (= (length args) 2))
+              (error "map: expects (proc list)"))
+            (:else (scm-map-step (first args) (nth args 1))))))
+      (scheme-env-bind!
+        env
+        "filter"
+        (fn
+          (args)
+          (cond
+            ((not (= (length args) 2))
+              (error "filter: expects (pred list)"))
+            (:else (scm-filter-step (first args) (nth args 1))))))
+      (scheme-env-bind!
+        env
+        "fold-left"
+        (fn
+          (args)
+          (cond
+            ((not (= (length args) 3))
+              (error "fold-left: expects (proc init list)"))
+            (:else
+              (scm-fold-left-step
+                (first args)
+                (nth args 1)
+                (nth args 2))))))
+      (scheme-env-bind!
+        env
+        "fold-right"
+        (fn
+          (args)
+          (cond
+            ((not (= (length args) 3))
+              (error "fold-right: expects (proc init list)"))
+            (:else
+              (scm-fold-right-step
+                (first args)
+                (nth args 1)
+                (nth args 2))))))
+      (scheme-env-bind!
+        env
+        "for-each"
+        (fn
+          (args)
+          (cond
+            ((not (= (length args) 2))
+              (error "for-each: expects (proc list)"))
+            (:else (scm-for-each-step (first args) (nth args 1))))))
+      (scheme-env-bind!
+        env
+        "apply"
+        (fn
+          (args)
+          (cond
+            ((not (= (length args) 2))
+              (error "apply: expects (proc args-list)"))
+            (:else (scheme-apply (first args) (nth args 1))))))
+      (scheme-env-bind!
+        env
+        "string-length"
+        (scm-unary
+          "string-length"
+          (fn (s) (string-length (scheme-string-value s)))))
+      (scheme-env-bind!
+        env
+        "string=?"
+        (scm-binary
+          "string=?"
+          (fn (a b) (= (scheme-string-value a) (scheme-string-value b)))))
+      (scheme-env-bind!
+        env
+        "string-append"
+        (fn
+          (args)
+          (scheme-string-make
+            (scm-fold-step
+              (fn (acc s) (str acc (scheme-string-value s)))
+              ""
+              args))))
+      (scheme-env-bind!
+        env
+        "substring"
+        (fn
+          (args)
+          (cond
+            ((not (= (length args) 3))
+              (error "substring: expects (str start end)"))
+            (:else
+              (scheme-string-make
+                (substring
+                  (scheme-string-value (first args))
+                  (nth args 1)
+                  (nth args 2)))))))
+      (scheme-env-bind!
+        env
+        "char=?"
+        (scm-binary
+          "char=?"
+          (fn (a b) (= (scheme-char-value a) (scheme-char-value b)))))
+      (scheme-env-bind! env "vector" (fn (args) (scheme-vector-make args)))
+      (scheme-env-bind!
+        env
+        "vector-length"
+        (scm-unary
+          "vector-length"
+          (fn (v) (length (scheme-vector-elements v)))))
+      (scheme-env-bind!
+        env
+        "vector-ref"
+        (scm-binary
+          "vector-ref"
+          (fn (v i) (nth (scheme-vector-elements v) i))))
+      (scheme-env-bind!
+        env
+        "vector->list"
+        (scm-unary "vector->list" (fn (v) (scheme-vector-elements v))))
+      (scheme-env-bind!
+        env
+        "list->vector"
+        (scm-unary "list->vector" (fn (xs) (scheme-vector-make xs))))
+      (scheme-env-bind!
+        env
+        "make-vector"
+        (fn
+          (args)
+          (cond
+            ((= (length args) 1)
+              (scheme-vector-make
+                (scm-make-vector-step (first args) nil (list))))
+            ((= (length args) 2)
+              (scheme-vector-make
+                (scm-make-vector-step
+                  (first args)
+                  (nth args 1)
+                  (list))))
+            (:else (error "make-vector: expects (n [fill])")))))
+      (scheme-env-bind! env "eqv?" (scm-binary "eqv?" (fn (a b) (= a b))))
+      (scheme-env-bind!
+        env
+        "equal?"
+        (scm-binary "equal?" (fn (a b) (= a b))))
+      (scheme-env-bind! env "eq?" (scm-binary "eq?" (fn (a b) (= a b))))
+      ;; ── call/cc (R7RS first-class continuations) ────────────
+      ;; Captures the host SX continuation, wraps it as a Scheme
+      ;; procedure (fn (vargs) ...) and passes it to the user proc.
+      ;; Calling the captured k with one value re-enters the
+      ;; continuation; with multiple values, passes them as a list.
+      (scheme-env-bind! env "call/cc"
+        (fn (args)
+          (cond
+            ((not (= (length args) 1))
+              (error "call/cc: expects 1 argument"))
+            (:else
+              (call/cc
+                (fn (k)
+                  (let ((scheme-k
+                          (fn (vargs)
+                            (cond
+                              ((= (length vargs) 1) (k (first vargs)))
+                              (:else (k vargs))))))
+                    (scheme-apply (first args) (list scheme-k)))))))))
+      (scheme-env-bind! env "call-with-current-continuation"
+        (refl-env-lookup env "call/cc"))
+      ;; ── R7RS exception primitives ──────────────────────────
+      ;; raise V — raises V as exception (host SX raise).
+      (scheme-env-bind! env "raise"
+        (fn (args)
+          (cond
+            ((not (= (length args) 1))
+              (error "raise: expects 1 argument"))
+            (:else (raise (first args))))))
+      ;; error MSG IRRITANTS... — convention: raise an error-object
+      ;; that's a dict {:scm-error MSG :irritants LIST}. The print
+      ;; surface (error-object-message / error-object-irritants)
+      ;; can pull these apart.
+      (scheme-env-bind! env "error"
+        (fn (args)
+          (cond
+            ((= (length args) 0) (error "error: expects (message [irritant...])"))
+            (:else
+              (raise {:scm-error (cond
+                                   ((scheme-string? (first args))
+                                     (scheme-string-value (first args)))
+                                   (:else (first args)))
+                      :irritants (rest args)})))))
+      (scheme-env-bind! env "error-object?"
+        (scm-unary "error-object?"
+          (fn (v) (and (dict? v) (string? (get v :scm-error))))))
+      (scheme-env-bind! env "error-object-message"
+        (scm-unary "error-object-message"
+          (fn (v) (scheme-string-make (get v :scm-error)))))
+      (scheme-env-bind! env "error-object-irritants"
+        (scm-unary "error-object-irritants"
+          (fn (v) (get v :irritants))))
+      ;; with-exception-handler HANDLER THUNK — runs THUNK; if it
+      ;; raises, calls HANDLER with the raised value (handler can
+      ;; itself raise or return a value). Implemented via host guard.
+      ;; with-exception-handler — catch THUNK's raise; if caught,
+      ;; call HANDLER. If HANDLER itself raises, propagate that to
+      ;; the outer scope (don't re-catch in this same guard, which
+      ;; would loop). The two-step outcome-sentinel pattern mirrors
+      ;; the `guard` special form's escape.
+      (scheme-env-bind! env "with-exception-handler"
+        (fn (args)
+          (cond
+            ((not (= (length args) 2))
+              (error "with-exception-handler: expects 2 arguments"))
+            (:else
+              (let ((handler (first args))
+                    (thunk (nth args 1)))
+                (let ((outcome
+                        (guard
+                          (e (true {:scm-weh-raised true :value e}))
+                          (scheme-apply thunk (list)))))
+                  (cond
+                    ((and (dict? outcome) (get outcome :scm-weh-raised))
+                      (scheme-apply handler (list (get outcome :value))))
+                    (:else outcome))))))))
+      ;; ── R7RS reflection: eval / environment accessors ───────
+      ;; eval EXPR ENV — apply the evaluator to a user-supplied AST.
+      (scheme-env-bind! env "eval"
+        (fn (args)
+          (cond
+            ((not (= (length args) 2))
+              (error "eval: expects (eval expr env)"))
+            (:else (scheme-eval (first args) (nth args 1))))))
+      ;; interaction-environment — the env we're currently building.
+      ;; The closure captures `env`, so each invocation of
+      ;; scheme-standard-env produces a distinct interaction env
+      ;; whose interaction-environment fn returns itself.
+      (scheme-env-bind! env "interaction-environment"
+        (fn (args)
+          (cond
+            ((not (= (length args) 0))
+              (error "interaction-environment: expects 0 args"))
+            (:else env))))
+      ;; null-environment — fresh empty env. R7RS ignores version arg.
+      (scheme-env-bind! env "null-environment"
+        (fn (args)
+          (cond
+            ((not (= (length args) 1))
+              (error "null-environment: expects (version)"))
+            (:else (scheme-make-env)))))
+      ;; scheme-report-environment — fresh full standard env.
+      (scheme-env-bind! env "scheme-report-environment"
+        (fn (args)
+          (cond
+            ((not (= (length args) 1))
+              (error "scheme-report-environment: expects (version)"))
+            (:else (scheme-standard-env)))))
+      (scheme-env-bind! env "environment?"
+        (scm-unary "environment?" (fn (v) (scheme-env? v))))
+      ;; dynamic-wind BEFORE THUNK AFTER — runs BEFORE, then THUNK,
+      ;; then AFTER. If THUNK raises, AFTER still runs before the
+      ;; raise propagates. This is the basic-correctness version;
+      ;; proper call/cc-escape interaction would need dynamic-extent
+      ;; tracking, deferred until needed.
+      (scheme-env-bind! env "dynamic-wind"
+        (fn (args)
+          (cond
+            ((not (= (length args) 3))
+              (error "dynamic-wind: expects (before thunk after)"))
+            (:else
+              (let ((before-thunk (first args))
+                    (mid-thunk (nth args 1))
+                    (after-thunk (nth args 2)))
+                (begin
+                  (scheme-apply before-thunk (list))
+                  (let ((outcome
+                          (guard
+                            (e (true {:scm-dw-raised true :value e}))
+                            (scheme-apply mid-thunk (list)))))
+                    (begin
+                      (scheme-apply after-thunk (list))
+                      (cond
+                        ((and (dict? outcome) (get outcome :scm-dw-raised))
+                          (raise (get outcome :value)))
+                        (:else outcome))))))))))
+      env)))

lib/scheme/scoreboard.md

@@ -0,0 +1,83 @@
+# Scheme-on-SX Scoreboard
+
+**All tests pass: 296 / 296 across 9 suites.**
+
+## Per-suite breakdown
+
+| Suite       | Passing | Covers |
+|-------------|--------:|--------|
+| parse       |     62  | R7RS lexer: numbers, strings, chars, vectors, lists, quote/quasi/unquote, line/block/datum comments |
+| eval        |     23  | Self-evaluating literals, symbol lookup, quote, primitive application |
+| syntax      |     49  | if/define/set!/begin/lambda/closures + let/let*/cond/when/unless/and/or |
+| runtime     |     78  | Standard env: variadic arithmetic, type predicates, list/string/char/vector ops, higher-order combinators |
+| control     |     25  | call/cc (escape), raise/guard/with-exception-handler, dynamic-wind |
+| macros      |     20  | define-syntax / syntax-rules incl. tail-rest ellipsis |
+| reflection  |     23  | eval / interaction-environment / null-environment / scheme-report-environment + quasiquote runtime |
+| records     |      9  | define-record-type with constructor / predicate / accessor / mutator |
+| modules     |      7  | define-library + import (minimal — no cond-expand / include / rename) |
+
+## Phases implemented
+
+- [x] Phase 1 — Parser
+- [x] Phase 2 — Evaluator + env.sx **third consumer**
+- [x] Phase 3 — Syntactic operators (if/lambda/define/set!/begin)
+- [x] Phase 3.5 — let/let*/cond/when/unless/and/or
+- [x] Phase 4 — Standard environment + set! cond-bugfix
+- [x] Phase 5a — call/cc
+- [x] Phase 5b — exceptions (raise/guard/with-exception-handler/error)
+- [x] Phase 5c — dynamic-wind (basic, no call/cc-escape tracking)
+- [x] Phase 6a — define-syntax + syntax-rules (no ellipsis)
+- [x] Phase 6b — syntax-rules ellipsis (tail-rest, single variable)
+- [x] Phase 7 — eval / interaction-environment **second consumer for evaluator.sx**
+- [x] Phase 8 — define-library + import (minimal)
+- [x] Phase 9 — define-record-type
+- [x] Phase 10 — quasiquote runtime **second consumer for quoting.sx**
+- [x] Phase 11 — test.sh + scoreboard
+
+## Deferred
+
+- **Phase 6c — hygiene** (scope-set / lifted-symbol Dybvig-style algorithm).
+  Would be the second consumer for the deferred `lib/guest/reflective/hygiene.sx`
+  research-grade kit. Current macros work for common patterns but can capture
+  caller bindings if a macro introduces same-named identifiers.
+
+- **Nested quasiquote depth tracking** — `` `\`x\` `` is not properly depth-aware;
+  matches Kernel's deferred state.
+
+- **R7RS module rich features**: cond-expand, include, include-library-declarations,
+  `(only ...)` / `(except ...)` / `(prefix ...)` / `(rename ...)` import sets.
+
+- **Dotted-pair `(a b . rest)` syntax** at the parser level. Lambda rest-args
+  currently use the `(lambda args ...)` form (bare symbol) instead.
+
+- **Full call/cc + dynamic-wind interaction**: re-entry/re-exit of dynamic
+  extents via continuations is not tracked. Pure-eval programs work; call/cc-
+  heavy code with dynamic-wind interleaving doesn't.
+
+## Reflective-kit consumption (chisel ledger)
+
+This Scheme port unlocks three reflective-kit extractions from the kernel-on-sx
+loop's original six-candidate list:
+
+| Kit                  | Status                                      |
+|----------------------|---------------------------------------------|
+| env.sx               | **Extracted** (third consumer; no adapter)  |
+| class-chain.sx       | n/a (no OO in Scheme)                       |
+| evaluator.sx         | **Unblocked** (second consumer ready)       |
+| quoting.sx           | **Unblocked** (second consumer ready)       |
+| hygiene.sx           | Awaiting Phase 6c (research-grade)          |
+| combiner.sx          | n/a (no fexprs in Scheme)                   |
+| short-circuit.sx     | n/a (Scheme `and`/`or` are syntactic, not operative) |
+
+The kit-extraction commits themselves are follow-on work — kit code is staged
+in the proposed sections of `plans/kernel-on-sx.md`; Scheme's consumer code
+satisfies the two-consumer rule for `evaluator.sx` and `quoting.sx`.
+
+## Substrate stats
+
+- parser.sx — 281 LoC
+- eval.sx — ~970 LoC
+- runtime.sx — ~580 LoC
+- Tests — ~1500 LoC across 9 files
+
+Total Scheme implementation ≈ 1830 LoC.

lib/scheme/test.sh

@@ -0,0 +1,92 @@
+#!/usr/bin/env bash
+# Scheme-on-SX test runner — runs all tests in one sx_server process.
+#
+# Usage:
+#   bash lib/scheme/test.sh          # run all suites
+#   bash lib/scheme/test.sh -v       # verbose (list each 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="${1:-}"
+
+# Suites: NAME RUNNER-FN PATH
+SUITES=(
+  "parse       scm-tests-run!         lib/scheme/tests/parse.sx"
+  "eval        scm-eval-tests-run!    lib/scheme/tests/eval.sx"
+  "syntax      scm-syn-tests-run!     lib/scheme/tests/syntax.sx"
+  "runtime     scm-rt-tests-run!      lib/scheme/tests/runtime.sx"
+  "control     scm-ctl-tests-run!     lib/scheme/tests/control.sx"
+  "macros      scm-mac-tests-run!     lib/scheme/tests/macros.sx"
+  "reflection  scm-ref-tests-run!     lib/scheme/tests/reflection.sx"
+  "records     scm-rec-tests-run!     lib/scheme/tests/records.sx"
+  "modules     scm-mod-tests-run!     lib/scheme/tests/modules.sx"
+)
+
+TMPFILE=$(mktemp); trap "rm -f $TMPFILE" EXIT
+EPOCH=1
+
+emit_load () { echo "(epoch $EPOCH)"; echo "(load \"$1\")"; EPOCH=$((EPOCH+1)); }
+emit_eval () { echo "(epoch $EPOCH)"; echo "(eval \"$1\")"; EPOCH=$((EPOCH+1)); }
+
+{
+  emit_load "lib/guest/lex.sx"
+  emit_load "lib/guest/reflective/env.sx"
+  emit_load "lib/scheme/parser.sx"
+  emit_load "lib/scheme/eval.sx"
+  emit_load "lib/scheme/runtime.sx"
+  for SUITE in "${SUITES[@]}"; do
+    read -r _NAME _RUNNER FILE <<< "$SUITE"
+    emit_load "$FILE"
+    emit_eval "($_RUNNER)"
+  done
+} > "$TMPFILE"
+
+OUTPUT=$(timeout 180 "$SX_SERVER" < "$TMPFILE" 2>&1 || true)
+
+# Final 9 outputs are the suite results. Parse each "{:passed N :failed N ..}".
+TOTAL_PASS=0
+TOTAL_FAIL=0
+FAILED_SUITES=()
+
+# Walk the output; for each suite, extract the {:passed ...} line.
+# The dict format from sx_server is {:passed N :failed N :total N :fails (...)}.
+LAST_DICT_LINES=$(echo "$OUTPUT" | grep -E '^\{:' || true)
+
+I=0
+while read -r LINE; do
+  [ -z "$LINE" ] && continue
+  P=$(echo "$LINE" | grep -oE ':passed [0-9]+' | awk '{print $2}')
+  F=$(echo "$LINE" | grep -oE ':failed [0-9]+' | awk '{print $2}')
+  [ -z "$P" ] && P=0
+  [ -z "$F" ] && F=0
+  SUITE_INFO="${SUITES[$I]}"
+  SUITE_NAME=$(echo "$SUITE_INFO" | awk '{print $1}')
+  TOTAL_PASS=$((TOTAL_PASS + P))
+  TOTAL_FAIL=$((TOTAL_FAIL + F))
+  if [ "$F" -gt 0 ]; then
+    FAILED_SUITES+=("$SUITE_NAME: $P/$((P+F))")
+    printf 'X %-12s %d/%d\n' "$SUITE_NAME" "$P" "$((P+F))"
+  elif [ "$VERBOSE" = "-v" ]; then
+    printf 'ok %-12s %d passed\n' "$SUITE_NAME" "$P"
+  fi
+  I=$((I+1))
+done <<< "$LAST_DICT_LINES"
+
+TOTAL=$((TOTAL_PASS + TOTAL_FAIL))
+if [ $TOTAL_FAIL -eq 0 ]; then
+  echo "ok $TOTAL_PASS/$TOTAL scheme-on-sx tests passed (${#SUITES[@]} suites)"
+else
+  echo "FAIL $TOTAL_PASS/$TOTAL passed, $TOTAL_FAIL failed:"
+  for S in "${FAILED_SUITES[@]}"; do echo "  $S"; done
+  exit 1
+fi

lib/scheme/tests/control.sx

@@ -0,0 +1,168 @@
+;; lib/scheme/tests/control.sx — call/cc, dynamic-wind, exceptions.
+
+(define scm-ctl-pass 0)
+(define scm-ctl-fail 0)
+(define scm-ctl-fails (list))
+
+(define
+  scm-ctl-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! scm-ctl-pass (+ scm-ctl-pass 1))
+      (begin
+        (set! scm-ctl-fail (+ scm-ctl-fail 1))
+        (append! scm-ctl-fails {:name name :actual actual :expected expected})))))
+
+(define
+  scm-ctl
+  (fn (src) (scheme-eval (scheme-parse src) (scheme-standard-env))))
+
+(define
+  scm-ctl-all
+  (fn
+    (src)
+    (scheme-eval-program (scheme-parse-all src) (scheme-standard-env))))
+
+;; ── call/cc — escape continuations ──────────────────────────────
+;; Single-shot only: when k is invoked, control jumps out of the
+;; surrounding call/cc and the result of the entire call/cc form is
+;; whatever was passed to k.
+
+(scm-ctl-test
+  "call/cc: no escape"
+  (scm-ctl "(call/cc (lambda (k) 42))")
+  42)
+(scm-ctl-test
+  "call/cc: simple escape"
+  (scm-ctl "(call/cc (lambda (k) (+ 1 (k 42))))")
+  42)
+(scm-ctl-test
+  "call/cc: escape past *"
+  (scm-ctl "(+ 10 (call/cc (lambda (k) (* 2 (k 5)))))")
+  15)
+(scm-ctl-test
+  "call/cc: alias call-with-current-continuation"
+  (scm-ctl "(call-with-current-continuation (lambda (k) (k 99)))")
+  99)
+(scm-ctl-test
+  "call/cc: doesn't escape if k unused"
+  (scm-ctl "(+ 1 (call/cc (lambda (k) (* 100 1))))")
+  101)
+
+;; ── call/cc as early-exit for list search ───────────────────────
+(scm-ctl-test
+  "call/cc: detect-via-escape"
+  (scm-ctl-all
+    "(define (detect pred xs)\n       (call/cc\n         (lambda (return)\n           (for-each\n             (lambda (x) (if (pred x) (return x) #f))\n             xs)\n           #f)))\n     (detect (lambda (x) (> x 10)) '(1 5 7 12 20))")
+  12)
+(scm-ctl-test
+  "call/cc: detect returns #f when no match"
+  (scm-ctl-all
+    "(define (detect pred xs)\n       (call/cc\n         (lambda (return)\n           (for-each\n             (lambda (x) (if (pred x) (return x) #f))\n             xs)\n           #f)))\n     (detect (lambda (x) (> x 100)) '(1 5 7))")
+  false)
+
+;; ── call/cc producing the captured k value ──────────────────────
+(scm-ctl-test
+  "call/cc: k is a procedure"
+  (scm-ctl "(procedure? (call/cc (lambda (k) k)))")
+  true)
+
+;; ── Exceptions: raise / guard / with-exception-handler / error ──
+(scm-ctl-test "raise + guard caught"
+  (scm-ctl "(guard (e (else 'caught)) (raise 'boom))") "caught")
+(scm-ctl-test "guard: number? matches"
+  (scm-ctl "(guard (e ((number? e) e) (else 'other)) (raise 42))") 42)
+(scm-ctl-test "guard: number? mismatches → else"
+  (scm-ctl "(guard (e ((number? e) e) (else 'other)) (raise 'sym))")
+  "other")
+(scm-ctl-test "guard: no error → body value"
+  (scm-ctl "(guard (e (else 'never)) 42)") 42)
+(scm-ctl-test "guard: first matching clause wins"
+  (scm-ctl
+    "(guard (e ((number? e) 'num) ((symbol? e) 'sym) (else 'other)) (raise 'foo))")
+  "sym")
+(scm-ctl-test "guard: re-raises when no clause matches"
+  (scm-ctl
+    "(guard (e (else 'outer)) (guard (e ((number? e) 'inner)) (raise 'not-a-number)))")
+  "outer")
+(scm-ctl-test "guard: var bound in clause body"
+  (scm-ctl "(guard (e ((symbol? e) e)) (raise 'the-symbol))")
+  "the-symbol")
+(scm-ctl-test "with-exception-handler: caught"
+  (scm-ctl
+    "(with-exception-handler (lambda (e) 'caught) (lambda () (raise 'oops)))")
+  "caught")
+(scm-ctl-test "with-exception-handler: no raise"
+  (scm-ctl
+    "(with-exception-handler (lambda (e) 99) (lambda () 42))")
+  42)
+(scm-ctl-test "with-exception-handler: handler sees the value"
+  (scm-ctl
+    "(with-exception-handler (lambda (e) (+ e 1)) (lambda () (raise 41)))")
+  42)
+(scm-ctl-test "error: irritants accessible"
+  (scm-ctl
+    "(guard (e ((error-object? e) (error-object-irritants e))) (error \"msg\" 1 2 3))")
+  (list 1 2 3))
+(scm-ctl-test "error: message accessible"
+  (scheme-string-value
+    (scm-ctl
+      "(guard (e ((error-object? e) (error-object-message e))) (error \"the-msg\"))"))
+  "the-msg")
+
+;; ── dynamic-wind ────────────────────────────────────────────────
+;; Basic version: runs before/thunk/after on success; before/after
+;; on raise (with the raise still propagating after the after-thunk).
+;; call/cc escape-out interaction is NOT yet tracked — deferred.
+
+(scm-ctl-test "dynamic-wind: ordering on success"
+  (scm-ctl-all
+    "(define log '())
+     (define (note x) (set! log (cons x log)))
+     (dynamic-wind
+       (lambda () (note 'before))
+       (lambda () (note 'thunk) 42)
+       (lambda () (note 'after)))
+     (reverse log)")
+  (list "before" "thunk" "after"))
+(scm-ctl-test "dynamic-wind: returns thunk value"
+  (scm-ctl
+    "(dynamic-wind (lambda () 'b) (lambda () 42) (lambda () 'a))") 42)
+(scm-ctl-test "dynamic-wind: after runs on raise"
+  (scm-ctl-all
+    "(define log '())
+     (define (note x) (set! log (cons x log)))
+     (guard (e (else 'caught))
+       (dynamic-wind
+         (lambda () (note 'before))
+         (lambda () (raise 'boom))
+         (lambda () (note 'after))))
+     (reverse log)")
+  (list "before" "after"))
+(scm-ctl-test "dynamic-wind: raise propagates after after-thunk"
+  (scm-ctl-all
+    "(guard (e (else e))
+       (dynamic-wind
+         (lambda () 'b)
+         (lambda () (raise 'the-raised))
+         (lambda () 'a)))")
+  "the-raised")
+(scm-ctl-test "dynamic-wind: nested"
+  (scm-ctl-all
+    "(define log '())
+     (define (note x) (set! log (cons x log)))
+     (dynamic-wind
+       (lambda () (note 'outer-before))
+       (lambda ()
+         (dynamic-wind
+           (lambda () (note 'inner-before))
+           (lambda () (note 'inner-thunk))
+           (lambda () (note 'inner-after))))
+       (lambda () (note 'outer-after)))
+     (reverse log)")
+  (list "outer-before" "inner-before" "inner-thunk"
+        "inner-after" "outer-after"))
+
+(define scm-ctl-tests-run! (fn () {:total (+ scm-ctl-pass scm-ctl-fail) :passed scm-ctl-pass :failed scm-ctl-fail :fails scm-ctl-fails}))

lib/scheme/tests/eval.sx

@@ -0,0 +1,162 @@
+;; lib/scheme/tests/eval.sx — exercises lib/scheme/eval.sx (Phase 2).
+
+(define scm-eval-pass 0)
+(define scm-eval-fail 0)
+(define scm-eval-fails (list))
+
+(define
+  scm-eval-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! scm-eval-pass (+ scm-eval-pass 1))
+      (begin
+        (set! scm-eval-fail (+ scm-eval-fail 1))
+        (append! scm-eval-fails {:name name :actual actual :expected expected})))))
+
+(define scm-eval-src (fn (src env) (scheme-eval (scheme-parse src) env)))
+
+;; A toy env with arithmetic + list primitives.
+(define
+  scm-test-env
+  (fn
+    ()
+    (let
+      ((env (scheme-make-env)))
+      (scheme-env-bind!
+        env
+        "+"
+        (fn (args) (+ (first args) (nth args 1))))
+      (scheme-env-bind!
+        env
+        "-"
+        (fn (args) (- (first args) (nth args 1))))
+      (scheme-env-bind!
+        env
+        "*"
+        (fn (args) (* (first args) (nth args 1))))
+      (scheme-env-bind! env "list" (fn (args) args))
+      env)))
+
+;; ── self-evaluating ──────────────────────────────────────────────
+(scm-eval-test
+  "lit: integer"
+  (scm-eval-src "42" (scheme-make-env))
+  42)
+(scm-eval-test "lit: float" (scm-eval-src "3.14" (scheme-make-env)) 3.14)
+(scm-eval-test "lit: #t" (scm-eval-src "#t" (scheme-make-env)) true)
+(scm-eval-test "lit: #f" (scm-eval-src "#f" (scheme-make-env)) false)
+(scm-eval-test
+  "lit: empty list"
+  (scm-eval-src "()" (scheme-make-env))
+  (list))
+(scm-eval-test
+  "lit: string"
+  (scheme-string? (scm-eval-src "\"hello\"" (scheme-make-env)))
+  true)
+(scm-eval-test
+  "lit: char"
+  (scheme-char? (scm-eval-src "#\\a" (scheme-make-env)))
+  true)
+(scm-eval-test
+  "lit: vector"
+  (scheme-vector? (scm-eval-src "#(1 2 3)" (scheme-make-env)))
+  true)
+
+;; ── symbol lookup ────────────────────────────────────────────────
+(scm-eval-test
+  "sym: bound"
+  (let
+    ((env (scheme-make-env)))
+    (scheme-env-bind! env "x" 100)
+    (scm-eval-src "x" env))
+  100)
+(scm-eval-test
+  "sym: parent chain"
+  (let
+    ((p (scheme-make-env)))
+    (scheme-env-bind! p "outer" 1)
+    (let
+      ((c (scheme-extend-env p)))
+      (scheme-env-bind! c "inner" 2)
+      (+ (scm-eval-src "outer" c) (scm-eval-src "inner" c))))
+  3)
+(scm-eval-test
+  "sym: shadowing"
+  (let
+    ((p (scheme-make-env)))
+    (scheme-env-bind! p "x" 1)
+    (let
+      ((c (scheme-extend-env p)))
+      (scheme-env-bind! c "x" 2)
+      (scm-eval-src "x" c)))
+  2)
+
+;; ── quote ────────────────────────────────────────────────────────
+(scm-eval-test
+  "quote: symbol"
+  (scm-eval-src "(quote foo)" (scheme-make-env))
+  "foo")
+(scm-eval-test
+  "quote: list"
+  (scm-eval-src "(quote (+ 1 2))" (scheme-make-env))
+  (list "+" 1 2))
+(scm-eval-test "quote: sugar 'x" (scm-eval-src "'x" (scheme-make-env)) "x")
+(scm-eval-test
+  "quote: sugar list"
+  (scm-eval-src "'(a b c)" (scheme-make-env))
+  (list "a" "b" "c"))
+(scm-eval-test
+  "quote: nested"
+  (scm-eval-src "''x" (scheme-make-env))
+  (list "quote" "x"))
+
+;; ── primitive application ────────────────────────────────────────
+(scm-eval-test "prim: +" (scm-eval-src "(+ 2 3)" (scm-test-env)) 5)
+(scm-eval-test
+  "prim: nested +"
+  (scm-eval-src "(+ (+ 1 2) (+ 3 4))" (scm-test-env))
+  10)
+(scm-eval-test
+  "prim: mixed ops"
+  (scm-eval-src "(- (* 4 5) (+ 3 2))" (scm-test-env))
+  15)
+(scm-eval-test
+  "prim: list builds SX list"
+  (scm-eval-src "(list 1 2 3)" (scm-test-env))
+  (list 1 2 3))
+(scm-eval-test
+  "prim: args eval in order"
+  (let
+    ((env (scm-test-env)))
+    (scheme-env-bind! env "a" 10)
+    (scheme-env-bind! env "b" 20)
+    (scm-eval-src "(+ a b)" env))
+  30)
+
+;; ── env-as-value (the third-consumer demonstration) ─────────────
+;; Scheme's env IS lib/guest/reflective/env.sx's canonical wire shape
+;; with no adapter cfg. Verify the kit primitives work directly.
+(scm-eval-test
+  "env: refl-env? on Scheme env"
+  (refl-env? (scheme-make-env))
+  true)
+(scm-eval-test
+  "env: lookup via kit"
+  (let
+    ((env (scheme-make-env)))
+    (refl-env-bind! env "name" "scheme")
+    (refl-env-lookup env "name"))
+  "scheme")
+(scm-eval-test
+  "env: find-frame walks parent"
+  (let
+    ((p (scheme-make-env)))
+    (refl-env-bind! p "root-binding" 99)
+    (let
+      ((c (scheme-extend-env p)))
+      (= (refl-env-find-frame c "root-binding") p)))
+  true)
+
+(define scm-eval-tests-run! (fn () {:total (+ scm-eval-pass scm-eval-fail) :passed scm-eval-pass :failed scm-eval-fail :fails scm-eval-fails}))

lib/scheme/tests/macros.sx

@@ -0,0 +1,155 @@
+;; lib/scheme/tests/macros.sx — define-syntax + syntax-rules.
+
+(define scm-mac-pass 0)
+(define scm-mac-fail 0)
+(define scm-mac-fails (list))
+
+(define
+  scm-mac-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! scm-mac-pass (+ scm-mac-pass 1))
+      (begin
+        (set! scm-mac-fail (+ scm-mac-fail 1))
+        (append! scm-mac-fails {:name name :actual actual :expected expected})))))
+
+(define
+  scm-mac
+  (fn
+    (src)
+    (scheme-eval-program (scheme-parse-all src) (scheme-standard-env))))
+
+;; ── Basic syntax-rules ──────────────────────────────────────────
+
+(scm-mac-test
+  "my-if true"
+  (scm-mac
+    "(define-syntax my-if (syntax-rules () ((_ c t e) (cond (c t) (else e)))))\n     (my-if #t 'yes 'no)")
+  "yes")
+(scm-mac-test
+  "my-if false"
+  (scm-mac
+    "(define-syntax my-if (syntax-rules () ((_ c t e) (cond (c t) (else e)))))\n     (my-if #f 'yes 'no)")
+  "no")
+(scm-mac-test
+  "double"
+  (scm-mac
+    "(define-syntax double (syntax-rules () ((_ x) (+ x x))))\n     (double 21)")
+  42)
+(scm-mac-test
+  "nested macro use"
+  (scm-mac
+    "(define-syntax double (syntax-rules () ((_ x) (+ x x))))\n     (double (double 5))")
+  20)
+
+;; ── Macro with multiple rules ───────────────────────────────────
+
+(scm-mac-test
+  "multi-rule: matches first"
+  (scm-mac
+    "(define-syntax twin (syntax-rules () ((_ a) a) ((_ a b) (+ a b))))\n     (twin 7)")
+  7)
+(scm-mac-test
+  "multi-rule: matches second"
+  (scm-mac
+    "(define-syntax twin (syntax-rules () ((_ a) a) ((_ a b) (+ a b))))\n     (twin 3 4)")
+  7)
+
+;; ── Macros wrapping control flow ────────────────────────────────
+
+(scm-mac-test
+  "swap idiom"
+  (scm-mac
+    "(define-syntax swap! (syntax-rules () ((_ a b) (let ((tmp a)) (set! a b) (set! b tmp)))))\n     (define x 1) (define y 2)\n     (swap! x y)\n     (list x y)")
+  (list 2 1))
+
+;; ── Macros that expand to expressions, not values ──────────────
+
+(scm-mac-test
+  "my-unless: true → empty"
+  (scm-mac
+    "(define-syntax my-unless (syntax-rules () ((_ c body) (if c 'skipped body))))\n     (my-unless #t 99)")
+  "skipped")
+(scm-mac-test
+  "my-unless: false → body"
+  (scm-mac
+    "(define-syntax my-unless (syntax-rules () ((_ c body) (if c 'skipped body))))\n     (my-unless #f 99)")
+  99)
+
+;; ── Macro with literal keyword ─────────────────────────────────
+
+(scm-mac-test
+  "literal: => recognised"
+  (scm-mac
+    "(define-syntax tag-arrow (syntax-rules (=>) ((_ a => b) (list 'arrow a b))))\n     (tag-arrow 1 => 2)")
+  (list "arrow" 1 2))
+
+;; ── Macro keyword passed through unevaluated ────────────────────
+
+(scm-mac-test
+  "list expansion preserves arg order"
+  (scm-mac
+    "(define-syntax tuple (syntax-rules () ((_ a b c) (list a b c))))\n     (tuple 1 2 3)")
+  (list 1 2 3))
+
+;; ── Macros + lambdas ────────────────────────────────────────────
+
+(scm-mac-test
+  "macro inside lambda"
+  (scm-mac
+    "(define-syntax sq (syntax-rules () ((_ x) (* x x))))\n     (define (f n) (+ (sq n) 1))\n     (f 5)")
+  26)
+
+;; ── Ellipsis patterns (Phase 6b — tail-rest single-variable) ────
+(scm-mac-test "ellipsis: empty rest"
+  (scm-mac
+    "(define-syntax my-list (syntax-rules () ((_ xs ...) (list xs ...))))
+     (my-list)")
+  (list))
+(scm-mac-test "ellipsis: list of values"
+  (scm-mac
+    "(define-syntax my-list (syntax-rules () ((_ xs ...) (list xs ...))))
+     (my-list 1 2 3 4)")
+  (list 1 2 3 4))
+(scm-mac-test "ellipsis: my-when truthy"
+  (scm-mac
+    "(define-syntax my-when (syntax-rules () ((_ c body ...) (if c (begin body ...)))))
+     (my-when #t 1 2 3)")
+  3)
+(scm-mac-test "ellipsis: my-when falsy returns nil"
+  (scm-mac
+    "(define-syntax my-when (syntax-rules () ((_ c body ...) (if c (begin body ...)))))
+     (my-when #f 1 2 3)")
+  nil)
+(scm-mac-test "ellipsis: begin-rebuild"
+  (scm-mac
+    "(define-syntax my-begin (syntax-rules () ((_ body ...) (let () body ...))))
+     (my-begin (define x 5) (define y 10) (+ x y))")
+  15)
+(scm-mac-test "ellipsis: variadic sum-em via fold"
+  (scm-mac
+    "(define-syntax sum-em (syntax-rules () ((_ xs ...) (fold-left + 0 (list xs ...)))))
+     (sum-em 1 2 3 4 5)")
+  15)
+(scm-mac-test "ellipsis: recursive my-and"
+  (scm-mac
+    "(define-syntax my-and
+       (syntax-rules ()
+         ((_) #t)
+         ((_ x) x)
+         ((_ x xs ...) (if x (my-and xs ...) #f))))
+     (my-and 1 2 3)")
+  3)
+(scm-mac-test "ellipsis: my-and short-circuits"
+  (scm-mac
+    "(define-syntax my-and
+       (syntax-rules ()
+         ((_) #t)
+         ((_ x) x)
+         ((_ x xs ...) (if x (my-and xs ...) #f))))
+     (my-and 1 #f 3)")
+  false)
+
+(define scm-mac-tests-run! (fn () {:total (+ scm-mac-pass scm-mac-fail) :passed scm-mac-pass :failed scm-mac-fail :fails scm-mac-fails}))

lib/scheme/tests/modules.sx

@@ -0,0 +1,73 @@
+;; lib/scheme/tests/modules.sx — define-library + import.
+
+(define scm-mod-pass 0)
+(define scm-mod-fail 0)
+(define scm-mod-fails (list))
+
+(define
+  scm-mod-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! scm-mod-pass (+ scm-mod-pass 1))
+      (begin
+        (set! scm-mod-fail (+ scm-mod-fail 1))
+        (append! scm-mod-fails {:name name :actual actual :expected expected})))))
+
+(define
+  scm-mod
+  (fn
+    (src)
+    (scheme-eval-program (scheme-parse-all src) (scheme-standard-env))))
+
+;; ── Basic define-library + import ───────────────────────────────
+
+(scm-mod-test
+  "simple lib: sq exported"
+  (scm-mod
+    "(define-library (my math)\n       (export sq)\n       (begin (define (sq x) (* x x))))\n     (import (my math))\n     (sq 5)")
+  25)
+(scm-mod-test
+  "lib: multiple exports"
+  (scm-mod
+    "(define-library (my math)\n       (export sq cube)\n       (begin\n         (define (sq x) (* x x))\n         (define (cube x) (* x x x))))\n     (import (my math))\n     (list (sq 5) (cube 3))")
+  (list 25 27))
+(scm-mod-test
+  "lib: single-symbol name"
+  (scm-mod
+    "(define-library (utils)\n       (export greet)\n       (begin (define (greet name) (string-append \"hi \" name))))\n     (import (utils))\n     (string=? (greet \"world\") \"hi world\")")
+  true)
+
+;; ── Unexported names are not visible ───────────────────────────
+
+(scm-mod-test
+  "lib: private name not exported"
+  (scm-mod
+    "(define-library (my math)\n       (export sq)\n       (begin\n         (define (sq x) (* x x))\n         (define (private-helper x) (+ x 1))))\n     (import (my math))\n     (guard (e (else 'unbound)) private-helper)")
+  "unbound")
+
+;; ── Library calls its own internals ─────────────────────────────
+
+(scm-mod-test
+  "lib: internal calls private fn"
+  (scm-mod
+    "(define-library (my math)\n       (export public-add1)\n       (begin\n         (define (private-inc x) (+ x 1))\n         (define (public-add1 x) (private-inc x))))\n     (import (my math))\n     (public-add1 41)")
+  42)
+
+;; ── Two libs, both imported ────────────────────────────────────
+
+(scm-mod-test
+  "two libs: both imported"
+  (scm-mod
+    "(define-library (a) (export af) (begin (define (af) 1)))\n     (define-library (b) (export bf) (begin (define (bf) 2)))\n     (import (a) (b))\n     (+ (af) (bf))")
+  3)
+
+;; ── Unknown library import errors ──────────────────────────────
+
+(scm-mod-test
+  "import: unknown lib errors"
+  (scm-mod "(guard (e (else 'unknown-lib)) (import (no such lib)))")
+  "unknown-lib")
+
+(define scm-mod-tests-run! (fn () {:total (+ scm-mod-pass scm-mod-fail) :passed scm-mod-pass :failed scm-mod-fail :fails scm-mod-fails}))

lib/scheme/tests/parse.sx

@@ -0,0 +1,177 @@
+;; lib/scheme/tests/parse.sx — exercises lib/scheme/parser.sx.
+
+(define scm-test-pass 0)
+(define scm-test-fail 0)
+(define scm-test-fails (list))
+
+(define
+  scm-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! scm-test-pass (+ scm-test-pass 1))
+      (begin
+        (set! scm-test-fail (+ scm-test-fail 1))
+        (append! scm-test-fails {:name name :actual actual :expected expected})))))
+
+;; ── numbers ───────────────────────────────────────────────────────
+(scm-test "num: integer" (scheme-parse "42") 42)
+(scm-test "num: zero" (scheme-parse "0") 0)
+(scm-test "num: negative" (scheme-parse "-17") -17)
+(scm-test "num: float" (scheme-parse "3.14") 3.14)
+(scm-test "num: exponent" (scheme-parse "1e3") 1000)
+(scm-test "num: negative float" (scheme-parse "-2.5") -2.5)
+
+;; ── booleans ──────────────────────────────────────────────────────
+(scm-test "bool: #t" (scheme-parse "#t") true)
+(scm-test "bool: #true" (scheme-parse "#true") true)
+(scm-test "bool: #f" (scheme-parse "#f") false)
+(scm-test "bool: #false" (scheme-parse "#false") false)
+
+;; ── strings ───────────────────────────────────────────────────────
+(scm-test "str: empty" (scheme-string-value (scheme-parse "\"\"")) "")
+(scm-test
+  "str: hello"
+  (scheme-string-value (scheme-parse "\"hello\""))
+  "hello")
+(scm-test "str: predicate" (scheme-string? (scheme-parse "\"x\"")) true)
+(scm-test "str: not symbol" (scheme-string? (scheme-parse "x")) false)
+(scm-test
+  "str: escape newline"
+  (scheme-string-value (scheme-parse "\"a\\nb\""))
+  "a\nb")
+(scm-test
+  "str: escape tab"
+  (scheme-string-value (scheme-parse "\"a\\tb\""))
+  "a\tb")
+(scm-test
+  "str: escape quote"
+  (scheme-string-value (scheme-parse "\"a\\\"b\""))
+  "a\"b")
+
+;; ── symbols ───────────────────────────────────────────────────────
+(scm-test "sym: word" (scheme-parse "foo") "foo")
+(scm-test "sym: hyphenated" (scheme-parse "set-car!") "set-car!")
+(scm-test "sym: question mark" (scheme-parse "null?") "null?")
+(scm-test "sym: arrow" (scheme-parse "->") "->")
+(scm-test "sym: lt-eq" (scheme-parse "<=") "<=")
+(scm-test "sym: bare plus" (scheme-parse "+") "+")
+(scm-test "sym: bare minus" (scheme-parse "-") "-")
+(scm-test "sym: dot-prefixed" (scheme-parse ".foo") ".foo")
+
+;; ── characters ────────────────────────────────────────────────────
+(scm-test "char: single" (scheme-char-value (scheme-parse "#\\a")) "a")
+(scm-test "char: space" (scheme-char-value (scheme-parse "#\\space")) " ")
+(scm-test "char: newline" (scheme-char-value (scheme-parse "#\\newline")) "\n")
+(scm-test "char: tab" (scheme-char-value (scheme-parse "#\\tab")) "\t")
+(scm-test "char: predicate" (scheme-char? (scheme-parse "#\\x")) true)
+(scm-test "char: digit" (scheme-char-value (scheme-parse "#\\5")) "5")
+
+;; ── vectors ───────────────────────────────────────────────────────
+(scm-test "vec: empty" (scheme-vector-elements (scheme-parse "#()")) (list))
+(scm-test
+  "vec: numbers"
+  (scheme-vector-elements (scheme-parse "#(1 2 3)"))
+  (list 1 2 3))
+(scm-test "vec: predicate" (scheme-vector? (scheme-parse "#(1)")) true)
+(scm-test "vec: not list" (scheme-vector? (scheme-parse "(1)")) false)
+;; Nested vector: SX `=` doesn't deep-compare dicts-with-list-values
+;; reliably under this CEK path, so check structure piecewise.
+(scm-test "vec: nested first"
+  (first (scheme-vector-elements (scheme-parse "#(a #(b c) d)"))) "a")
+(scm-test "vec: nested second is vector"
+  (scheme-vector?
+    (nth (scheme-vector-elements (scheme-parse "#(a #(b c) d)")) 1))
+  true)
+(scm-test "vec: nested second elements"
+  (scheme-vector-elements
+    (nth (scheme-vector-elements (scheme-parse "#(a #(b c) d)")) 1))
+  (list "b" "c"))
+
+;; ── lists ─────────────────────────────────────────────────────────
+(scm-test "list: empty" (scheme-parse "()") (list))
+(scm-test "list: flat" (scheme-parse "(a b c)") (list "a" "b" "c"))
+(scm-test
+  "list: nested"
+  (scheme-parse "(a (b c) d)")
+  (list "a" (list "b" "c") "d"))
+(scm-test
+  "list: mixed atoms"
+  (scheme-parse "(1 #t foo)")
+  (list 1 true "foo"))
+
+;; ── reader macros ─────────────────────────────────────────────────
+(scm-test "quote: 'foo" (scheme-parse "'foo") (list "quote" "foo"))
+(scm-test
+  "quote: '(a b c)"
+  (scheme-parse "'(a b c)")
+  (list "quote" (list "a" "b" "c")))
+(scm-test "quasiquote: `x" (scheme-parse "`x") (list "quasiquote" "x"))
+(scm-test "unquote: ,x" (scheme-parse ",x") (list "unquote" "x"))
+(scm-test
+  "unquote-splicing: ,@x"
+  (scheme-parse ",@x")
+  (list "unquote-splicing" "x"))
+(scm-test
+  "qq mix"
+  (scheme-parse "`(a ,b ,@c)")
+  (list
+    "quasiquote"
+    (list "a" (list "unquote" "b") (list "unquote-splicing" "c"))))
+
+;; ── comments ──────────────────────────────────────────────────────
+(scm-test "comment: line" (scheme-parse "; nope\n42") 42)
+(scm-test "comment: trailing" (scheme-parse "42 ; tail") 42)
+(scm-test
+  "comment: inside list"
+  (scheme-parse "(a ; mid\n  b)")
+  (list "a" "b"))
+(scm-test "comment: block simple" (scheme-parse "#| skip |# 42") 42)
+(scm-test
+  "comment: block nested"
+  (scheme-parse "#| outer #| inner |# done |# 42")
+  42)
+(scm-test "comment: datum #;" (scheme-parse "#;skipme 42") 42)
+(scm-test
+  "comment: datum skips list"
+  (scheme-parse "#;(1 2 3) 42")
+  42)
+
+;; ── parse-all ─────────────────────────────────────────────────────
+(scm-test "all: empty" (scheme-parse-all "") (list))
+(scm-test
+  "all: three forms"
+  (scheme-parse-all "1 2 3")
+  (list 1 2 3))
+(scm-test
+  "all: mixed"
+  (scheme-parse-all "(if #t 1 2) foo")
+  (list (list "if" true 1 2) "foo"))
+
+;; ── classic Scheme idioms ─────────────────────────────────────────
+(scm-test
+  "classic: lambda"
+  (scheme-parse "(lambda (x) (+ x 1))")
+  (list "lambda" (list "x") (list "+" "x" 1)))
+(scm-test
+  "classic: define"
+  (scheme-parse "(define (sq x) (* x x))")
+  (list "define" (list "sq" "x") (list "*" "x" "x")))
+(scm-test
+  "classic: let"
+  (scheme-parse "(let ((x 1) (y 2)) (+ x y))")
+  (list
+    "let"
+    (list (list "x" 1) (list "y" 2))
+    (list "+" "x" "y")))
+(scm-test
+  "classic: if"
+  (scheme-parse "(if (zero? n) 1 (* n (fact (- n 1))))")
+  (list
+    "if"
+    (list "zero?" "n")
+    1
+    (list "*" "n" (list "fact" (list "-" "n" 1)))))
+
+(define scm-tests-run! (fn () {:total (+ scm-test-pass scm-test-fail) :passed scm-test-pass :failed scm-test-fail :fails scm-test-fails}))

lib/scheme/tests/records.sx

@@ -0,0 +1,96 @@
+;; lib/scheme/tests/records.sx — define-record-type.
+
+(define scm-rec-pass 0)
+(define scm-rec-fail 0)
+(define scm-rec-fails (list))
+
+(define
+  scm-rec-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! scm-rec-pass (+ scm-rec-pass 1))
+      (begin
+        (set! scm-rec-fail (+ scm-rec-fail 1))
+        (append! scm-rec-fails {:name name :actual actual :expected expected})))))
+
+(define
+  scm-rec
+  (fn (src) (scheme-eval (scheme-parse src) (scheme-standard-env))))
+
+(define
+  scm-rec-all
+  (fn
+    (src)
+    (scheme-eval-program (scheme-parse-all src) (scheme-standard-env))))
+
+;; ── Basic record: point ─────────────────────────────────────────
+
+(scm-rec-test
+  "point: constructor + predicate"
+  (scm-rec-all
+    "(define-record-type point\n       (make-point x y) point?\n       (x point-x) (y point-y))\n     (point? (make-point 3 4))")
+  true)
+(scm-rec-test
+  "point: accessor x"
+  (scm-rec-all
+    "(define-record-type point\n       (make-point x y) point?\n       (x point-x) (y point-y))\n     (point-x (make-point 3 4))")
+  3)
+(scm-rec-test
+  "point: accessor y"
+  (scm-rec-all
+    "(define-record-type point\n       (make-point x y) point?\n       (x point-x) (y point-y))\n     (point-y (make-point 3 4))")
+  4)
+(scm-rec-test
+  "point: predicate false on number"
+  (scm-rec-all
+    "(define-record-type point\n       (make-point x y) point?\n       (x point-x) (y point-y))\n     (point? 42)")
+  false)
+
+;; ── Mutator ─────────────────────────────────────────────────────
+
+(scm-rec-test
+  "point: mutator"
+  (scm-rec-all
+    "(define-record-type point\n       (make-point x y) point?\n       (x point-x) (y point-y set-point-y!))\n     (define p (make-point 3 4))\n     (set-point-y! p 99)\n     (point-y p)")
+  99)
+
+;; ── Multiple record types are distinct ──────────────────────────
+
+(scm-rec-test
+  "distinct types: point? false on circle"
+  (scm-rec-all
+    "(define-record-type point\n       (make-point x y) point? (x point-x) (y point-y))\n     (define-record-type circle\n       (make-circle r) circle? (r circle-r))\n     (point? (make-circle 5))")
+  false)
+(scm-rec-test
+  "distinct types: circle? true on circle"
+  (scm-rec-all
+    "(define-record-type point\n       (make-point x y) point? (x point-x) (y point-y))\n     (define-record-type circle\n       (make-circle r) circle? (r circle-r))\n     (circle? (make-circle 5))")
+  true)
+
+;; ── Records as first-class values ───────────────────────────────
+
+(scm-rec-test
+  "record in a list"
+  (scm-rec-all
+    "(define-record-type box\n       (make-box v) box? (v box-v))\n     (map box-v (list (make-box 1) (make-box 2) (make-box 3)))")
+  (list 1 2 3))
+
+;; ── Records via map/filter ──────────────────────────────────────
+
+(scm-rec-test
+  "filter records by predicate"
+  (scm-rec-all
+    "(define-record-type box\n       (make-box v) box? (v box-v))\n     (length\n       (filter (lambda (b) (> (box-v b) 5))\n               (list (make-box 1) (make-box 7) (make-box 3) (make-box 10)))))")
+  2)
+
+;; ── Constructor arity errors ────────────────────────────────────
+
+(scm-rec-test
+  "ctor: wrong arity errors"
+  (scm-rec-all
+    "(define-record-type point (make-point x y) point? (x point-x) (y point-y))\n     (guard (e (else 'arity-err)) (make-point 1))")
+  "arity-err")
+
+(define scm-rec-tests-run! (fn () {:total (+ scm-rec-pass scm-rec-fail) :passed scm-rec-pass :failed scm-rec-fail :fails scm-rec-fails}))

lib/scheme/tests/reflection.sx

@@ -0,0 +1,130 @@
+;; lib/scheme/tests/reflection.sx — Phase 7 reflective primitives.
+
+(define scm-ref-pass 0)
+(define scm-ref-fail 0)
+(define scm-ref-fails (list))
+
+(define
+  scm-ref-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! scm-ref-pass (+ scm-ref-pass 1))
+      (begin
+        (set! scm-ref-fail (+ scm-ref-fail 1))
+        (append! scm-ref-fails {:name name :actual actual :expected expected})))))
+
+(define
+  scm-ref
+  (fn (src) (scheme-eval (scheme-parse src) (scheme-standard-env))))
+
+(define
+  scm-ref-all
+  (fn
+    (src)
+    (scheme-eval-program (scheme-parse-all src) (scheme-standard-env))))
+
+;; ── eval ─────────────────────────────────────────────────────────
+
+(scm-ref-test
+  "eval: arithmetic"
+  (scm-ref "(eval '(+ 1 2 3) (interaction-environment))")
+  6)
+(scm-ref-test
+  "eval: nested"
+  (scm-ref "(eval '(* (+ 1 2) (- 5 1)) (interaction-environment))")
+  12)
+(scm-ref-test
+  "eval: constructed form"
+  (scm-ref "(eval (list '+ 10 20) (interaction-environment))")
+  30)
+(scm-ref-test
+  "eval: variable reference"
+  (scm-ref-all "(define x 42) (eval 'x (interaction-environment))")
+  42)
+
+;; ── interaction-environment ─────────────────────────────────────
+
+(scm-ref-test
+  "interaction-environment: is an env"
+  (scm-ref "(environment? (interaction-environment))")
+  true)
+(scm-ref-test
+  "interaction-environment: define persists"
+  (scm-ref-all
+    "(define ie (interaction-environment))\n     (eval '(define stashed 99) ie)\n     (eval 'stashed ie)")
+  99)
+(scm-ref-test
+  "interaction-environment: same env across calls"
+  (scm-ref-all
+    "(define a (interaction-environment))\n     (define b (interaction-environment))\n     (eqv? a b)")
+  true)
+
+;; ── null-environment ────────────────────────────────────────────
+
+(scm-ref-test
+  "null-environment: is an env"
+  (scm-ref "(environment? (null-environment 7))")
+  true)
+(scm-ref-test
+  "null-environment: has no + binding"
+  (scm-ref-all
+    "(define ne (null-environment 7))\n     (guard (e (else 'unbound)) (eval '+ ne))")
+  "unbound")
+
+;; ── scheme-report-environment ───────────────────────────────────
+
+(scm-ref-test
+  "scheme-report-environment: is an env"
+  (scm-ref "(environment? (scheme-report-environment 7))")
+  true)
+(scm-ref-test
+  "scheme-report-environment: has +"
+  (scm-ref "(eval '(+ 1 2) (scheme-report-environment 7))")
+  3)
+(scm-ref-test
+  "scheme-report-environment: distinct from interaction"
+  (scm-ref-all
+    "(define ie (interaction-environment))\n     (define re (scheme-report-environment 7))\n     (eval '(define only-in-ie 1) ie)\n     (guard (e (else 'unbound)) (eval 'only-in-ie re))")
+  "unbound")
+
+;; ── eval with explicit env for sandboxing ──────────────────────
+
+(scm-ref-test
+  "eval: sandbox with null-environment"
+  (scm-ref-all
+    "(define sandbox (null-environment 7))\n     (guard (e (else 'unbound))\n       (eval '(+ 1 1) sandbox))")
+  "unbound")
+
+;; ── quasiquote / unquote / unquote-splicing ─────────────────────
+(scm-ref-test "qq: plain atom"
+  (scm-ref "`hello") "hello")
+(scm-ref-test "qq: plain list"
+  (scm-ref "`(a b c)") (list "a" "b" "c"))
+(scm-ref-test "qq: unquote substitutes value"
+  (scm-ref-all "(define x 42) `(a ,x b)")
+  (list "a" 42 "b"))
+(scm-ref-test "qq: unquote-splicing splices list"
+  (scm-ref-all "(define xs '(1 2 3)) `(a ,@xs b)")
+  (list "a" 1 2 3 "b"))
+(scm-ref-test "qq: splice at start"
+  (scm-ref-all "(define xs '(1 2)) `(,@xs c)")
+  (list 1 2 "c"))
+(scm-ref-test "qq: splice at end"
+  (scm-ref-all "(define xs '(9 8)) `(a b ,@xs)")
+  (list "a" "b" 9 8))
+(scm-ref-test "qq: nested list with unquote"
+  (scm-ref-all "(define x 5) `(a (b ,x) c)")
+  (list "a" (list "b" 5) "c"))
+(scm-ref-test "qq: unquote evaluates expression"
+  (scm-ref "`(a ,(+ 1 2) b)")
+  (list "a" 3 "b"))
+(scm-ref-test "qq: error on splicing non-list"
+  (scm-ref-all
+    "(define x 42) (guard (e (else 'raised)) `(a ,@x b))")
+  "raised")
+(scm-ref-test "qq: bare unquote at top level errors"
+  (scm-ref "(guard (e (else 'raised)) (unquote 5))") "raised")
+
+(define scm-ref-tests-run! (fn () {:total (+ scm-ref-pass scm-ref-fail) :passed scm-ref-pass :failed scm-ref-fail :fails scm-ref-fails}))

lib/scheme/tests/runtime.sx

@@ -0,0 +1,213 @@
+;; lib/scheme/tests/runtime.sx — exercises the standard env.
+
+(define scm-rt-pass 0)
+(define scm-rt-fail 0)
+(define scm-rt-fails (list))
+
+(define
+  scm-rt-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! scm-rt-pass (+ scm-rt-pass 1))
+      (begin
+        (set! scm-rt-fail (+ scm-rt-fail 1))
+        (append! scm-rt-fails {:name name :actual actual :expected expected})))))
+
+(define
+  scm-rt
+  (fn (src) (scheme-eval (scheme-parse src) (scheme-standard-env))))
+
+(define
+  scm-rt-all
+  (fn
+    (src)
+    (scheme-eval-program (scheme-parse-all src) (scheme-standard-env))))
+
+;; ── Variadic arithmetic ─────────────────────────────────────────
+(scm-rt-test "+: zero" (scm-rt "(+)") 0)
+(scm-rt-test "+: one" (scm-rt "(+ 7)") 7)
+(scm-rt-test "+: many" (scm-rt "(+ 1 2 3 4 5)") 15)
+(scm-rt-test "-: one" (scm-rt "(- 10)") -10)
+(scm-rt-test "-: many" (scm-rt "(- 100 1 2 3)") 94)
+(scm-rt-test "*: zero" (scm-rt "(*)") 1)
+(scm-rt-test "*: many" (scm-rt "(* 1 2 3 4)") 24)
+(scm-rt-test "/: two" (scm-rt "(/ 20 5)") 4)
+
+;; ── Chained comparison ──────────────────────────────────────────
+(scm-rt-test "<: chained" (scm-rt "(< 1 2 3 4 5)") true)
+(scm-rt-test "<: not strict" (scm-rt "(< 1 2 2 3)") false)
+(scm-rt-test ">: chained" (scm-rt "(> 5 4 3 2 1)") true)
+(scm-rt-test "<=: with equality" (scm-rt "(<= 1 1 2 3 3)") true)
+(scm-rt-test "=: chained" (scm-rt "(= 7 7 7)") true)
+
+;; ── Numerical ───────────────────────────────────────────────────
+(scm-rt-test "abs neg" (scm-rt "(abs -5)") 5)
+(scm-rt-test "abs pos" (scm-rt "(abs 5)") 5)
+(scm-rt-test "min" (scm-rt "(min 3 1 4 1 5)") 1)
+(scm-rt-test "max" (scm-rt "(max 3 1 4 1 5)") 5)
+(scm-rt-test "modulo" (scm-rt "(modulo 10 3)") 1)
+(scm-rt-test "zero? 0" (scm-rt "(zero? 0)") true)
+(scm-rt-test "zero? 1" (scm-rt "(zero? 1)") false)
+(scm-rt-test "positive?" (scm-rt "(positive? 5)") true)
+(scm-rt-test "negative?" (scm-rt "(negative? -5)") true)
+
+;; ── Type predicates ─────────────────────────────────────────────
+(scm-rt-test "number? int" (scm-rt "(number? 42)") true)
+(scm-rt-test "number? str" (scm-rt "(number? \"hi\")") false)
+(scm-rt-test "boolean? #t" (scm-rt "(boolean? #t)") true)
+(scm-rt-test "boolean? 0" (scm-rt "(boolean? 0)") false)
+(scm-rt-test "string? str" (scm-rt "(string? \"hi\")") true)
+(scm-rt-test "string? sym" (scm-rt "(string? 'foo)") false)
+(scm-rt-test "symbol? sym" (scm-rt "(symbol? 'foo)") true)
+(scm-rt-test "null? ()" (scm-rt "(null? '())") true)
+(scm-rt-test "null? (1)" (scm-rt "(null? '(1))") false)
+(scm-rt-test "pair? (1)" (scm-rt "(pair? '(1))") true)
+(scm-rt-test "pair? ()" (scm-rt "(pair? '())") false)
+(scm-rt-test "procedure? lambda" (scm-rt "(procedure? (lambda (x) x))") true)
+(scm-rt-test "procedure? +" (scm-rt "(procedure? +)") true)
+(scm-rt-test "procedure? 42" (scm-rt "(procedure? 42)") false)
+(scm-rt-test "not #t" (scm-rt "(not #t)") false)
+(scm-rt-test "not #f" (scm-rt "(not #f)") true)
+(scm-rt-test "not 0" (scm-rt "(not 0)") false)
+
+;; ── List operations ─────────────────────────────────────────────
+(scm-rt-test
+  "cons"
+  (scm-rt "(cons 1 '(2 3))")
+  (list 1 2 3))
+(scm-rt-test "car" (scm-rt "(car '(1 2 3))") 1)
+(scm-rt-test "cdr" (scm-rt "(cdr '(1 2 3))") (list 2 3))
+(scm-rt-test
+  "list builds"
+  (scm-rt "(list 1 2 3)")
+  (list 1 2 3))
+(scm-rt-test "list empty" (scm-rt "(list)") (list))
+(scm-rt-test "length 3" (scm-rt "(length '(a b c))") 3)
+(scm-rt-test "length 0" (scm-rt "(length '())") 0)
+(scm-rt-test
+  "reverse"
+  (scm-rt "(reverse '(1 2 3))")
+  (list 3 2 1))
+(scm-rt-test "reverse empty" (scm-rt "(reverse '())") (list))
+(scm-rt-test
+  "append two"
+  (scm-rt "(append '(1 2) '(3 4))")
+  (list 1 2 3 4))
+(scm-rt-test
+  "append three"
+  (scm-rt "(append '(1) '(2) '(3))")
+  (list 1 2 3))
+(scm-rt-test "append empty" (scm-rt "(append)") (list))
+
+;; ── Higher-order combinators ────────────────────────────────────
+(scm-rt-test
+  "map square"
+  (scm-rt "(map (lambda (x) (* x x)) '(1 2 3 4))")
+  (list 1 4 9 16))
+(scm-rt-test
+  "map with primitive"
+  (scm-rt-all "(define inc (lambda (x) (+ x 1))) (map inc '(10 20 30))")
+  (list 11 21 31))
+(scm-rt-test
+  "filter positives"
+  (scm-rt "(filter positive? '(-2 -1 0 1 2))")
+  (list 1 2))
+(scm-rt-test
+  "filter empty result"
+  (scm-rt "(filter (lambda (x) #f) '(1 2 3))")
+  (list))
+(scm-rt-test
+  "fold-left sum"
+  (scm-rt "(fold-left + 0 '(1 2 3 4 5))")
+  15)
+(scm-rt-test
+  "fold-left build list"
+  (scm-rt "(fold-left (lambda (acc x) (cons x acc)) '() '(1 2 3))")
+  (list 3 2 1))
+(scm-rt-test
+  "fold-right preserves order"
+  (scm-rt "(fold-right cons '() '(1 2 3))")
+  (list 1 2 3))
+(scm-rt-test
+  "for-each side effect"
+  (let
+    ((env (scheme-standard-env)))
+    (scheme-eval-program
+      (scheme-parse-all
+        "(define sum 0) (for-each (lambda (n) (set! sum (+ sum n))) '(1 2 3 4 5)) sum")
+      env))
+  15)
+
+;; ── apply ───────────────────────────────────────────────────────
+(scm-rt-test "apply +" (scm-rt "(apply + '(1 2 3 4 5))") 15)
+(scm-rt-test
+  "apply lambda"
+  (scm-rt "(apply (lambda (a b c) (+ a (* b c))) '(1 2 3))")
+  7)
+(scm-rt-test
+  "apply via map"
+  (scm-rt "(apply + (map (lambda (x) (* x x)) '(1 2 3)))")
+  14)
+
+;; ── String / char / vector ──────────────────────────────────────
+(scm-rt-test "string-length" (scm-rt "(string-length \"hello\")") 5)
+(scm-rt-test "string=? same" (scm-rt "(string=? \"abc\" \"abc\")") true)
+(scm-rt-test "string=? diff" (scm-rt "(string=? \"abc\" \"abd\")") false)
+(scm-rt-test
+  "string-append"
+  (scheme-string-value (scm-rt "(string-append \"hello\" \" \" \"world\")"))
+  "hello world")
+(scm-rt-test "vector?" (scm-rt "(vector? #(1 2 3))") true)
+(scm-rt-test "vector-length" (scm-rt "(vector-length #(1 2 3))") 3)
+(scm-rt-test "vector-ref" (scm-rt "(vector-ref #(10 20 30) 1)") 20)
+(scm-rt-test
+  "vector->list"
+  (scm-rt "(vector->list #(1 2 3))")
+  (list 1 2 3))
+
+;; ── Classic Scheme programs ─────────────────────────────────────
+(scm-rt-test
+  "factorial 5"
+  (scm-rt-all
+    "(define (fact n) (if (<= n 1) 1 (* n (fact (- n 1))))) (fact 5)")
+  120)
+(scm-rt-test
+  "factorial 10"
+  (scm-rt-all
+    "(define (fact n) (if (<= n 1) 1 (* n (fact (- n 1))))) (fact 10)")
+  3628800)
+(scm-rt-test
+  "fib 10"
+  (scm-rt-all
+    "(define (fib n) (if (< n 2) n (+ (fib (- n 1)) (fib (- n 2))))) (fib 10)")
+  55)
+(scm-rt-test
+  "sum via reduce"
+  (scm-rt "(fold-left + 0 (map (lambda (x) (* x x)) '(1 2 3 4 5)))")
+  55)
+(scm-rt-test
+  "length via reduce"
+  (scm-rt-all
+    "(define (len xs) (fold-left (lambda (acc _) (+ acc 1)) 0 xs)) (len '(a b c d))")
+  4)
+(scm-rt-test
+  "Y-ish reverse"
+  (scm-rt-all
+    "(define (rev xs) (if (null? xs) '() (append (rev (cdr xs)) (list (car xs))))) (rev '(1 2 3 4))")
+  (list 4 3 2 1))
+
+;; ── env-as-value (kit consumer demo) ────────────────────────────
+(scm-rt-test
+  "env: standard-env is refl-env"
+  (refl-env? (scheme-standard-env))
+  true)
+(scm-rt-test
+  "env: kit lookup finds primitive"
+  (let
+    ((env (scheme-standard-env)))
+    (callable? (refl-env-lookup env "+")))
+  true)
+
+(define scm-rt-tests-run! (fn () {:total (+ scm-rt-pass scm-rt-fail) :passed scm-rt-pass :failed scm-rt-fail :fails scm-rt-fails}))

lib/scheme/tests/syntax.sx

@@ -0,0 +1,288 @@
+;; lib/scheme/tests/syntax.sx — exercises Phase 3 syntactic operators.
+
+(define scm-syn-pass 0)
+(define scm-syn-fail 0)
+(define scm-syn-fails (list))
+
+(define
+  scm-syn-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! scm-syn-pass (+ scm-syn-pass 1))
+      (begin
+        (set! scm-syn-fail (+ scm-syn-fail 1))
+        (append! scm-syn-fails {:name name :actual actual :expected expected})))))
+
+(define scm-syn-eval (fn (src env) (scheme-eval (scheme-parse src) env)))
+
+(define
+  scm-syn-eval-all
+  (fn (src env) (scheme-eval-program (scheme-parse-all src) env)))
+
+;; Test env with arithmetic primitives.
+(define
+  scm-syn-env
+  (fn
+    ()
+    (let
+      ((env (scheme-make-env)))
+      (scheme-env-bind!
+        env
+        "+"
+        (fn (args) (+ (first args) (nth args 1))))
+      (scheme-env-bind!
+        env
+        "-"
+        (fn (args) (- (first args) (nth args 1))))
+      (scheme-env-bind!
+        env
+        "*"
+        (fn (args) (* (first args) (nth args 1))))
+      (scheme-env-bind!
+        env
+        "/"
+        (fn (args) (/ (first args) (nth args 1))))
+      (scheme-env-bind!
+        env
+        "<="
+        (fn (args) (<= (first args) (nth args 1))))
+      (scheme-env-bind!
+        env
+        "<"
+        (fn (args) (< (first args) (nth args 1))))
+      (scheme-env-bind!
+        env
+        "="
+        (fn (args) (= (first args) (nth args 1))))
+      (scheme-env-bind! env "list" (fn (args) args))
+      (scheme-env-bind!
+        env
+        "cons"
+        (fn (args) (cons (first args) (nth args 1))))
+      (scheme-env-bind! env "car" (fn (args) (first (first args))))
+      (scheme-env-bind! env "cdr" (fn (args) (rest (first args))))
+      env)))
+
+;; ── if ───────────────────────────────────────────────────────────
+(scm-syn-test
+  "if: true"
+  (scm-syn-eval "(if #t 1 2)" (scm-syn-env))
+  1)
+(scm-syn-test
+  "if: false"
+  (scm-syn-eval "(if #f 1 2)" (scm-syn-env))
+  2)
+(scm-syn-test
+  "if: predicate"
+  (scm-syn-eval "(if (<= 1 2) 99 nope)" (scm-syn-env))
+  99)
+(scm-syn-test
+  "if: no else returns nil"
+  (scm-syn-eval "(if #f 99)" (scm-syn-env))
+  nil)
+(scm-syn-test
+  "if: truthy non-#f"
+  (scm-syn-eval "(if 0 'yes 'no)" (scm-syn-env))
+  "yes")
+
+;; ── define ───────────────────────────────────────────────────────
+(scm-syn-test
+  "define: bind value"
+  (let
+    ((env (scm-syn-env)))
+    (scm-syn-eval "(define x 42)" env)
+    (scm-syn-eval "x" env))
+  42)
+(scm-syn-test
+  "define: function sugar"
+  (let
+    ((env (scm-syn-env)))
+    (scm-syn-eval-all "(define (double n) (+ n n)) (double 21)" env))
+  42)
+(scm-syn-test
+  "define: redefine"
+  (let
+    ((env (scm-syn-env)))
+    (scm-syn-eval-all "(define x 1) (define x 2) x" env))
+  2)
+
+;; ── set! ─────────────────────────────────────────────────────────
+(scm-syn-test
+  "set!: mutate"
+  (let
+    ((env (scm-syn-env)))
+    (scm-syn-eval-all "(define x 1) (set! x 99) x" env))
+  99)
+(scm-syn-test
+  "set!: walks parent"
+  (let
+    ((env (scm-syn-env)))
+    (scm-syn-eval-all "(define x 1) ((lambda () (set! x 100))) x" env))
+  100)
+(scm-syn-test
+  "set!: errors on unbound"
+  (guard
+    (e (true :raised))
+    (scm-syn-eval-all "(set! never-defined 1)" (scm-syn-env)))
+  :raised)
+
+;; ── begin ────────────────────────────────────────────────────────
+(scm-syn-test
+  "begin: empty returns nil"
+  (scm-syn-eval "(begin)" (scm-syn-env))
+  nil)
+(scm-syn-test
+  "begin: returns last"
+  (scm-syn-eval "(begin 1 2 3)" (scm-syn-env))
+  3)
+(scm-syn-test
+  "begin: side effects in order"
+  (let
+    ((env (scm-syn-env)))
+    (scm-syn-eval-all
+      "(define x 0) (begin (set! x 1) (set! x 2) (set! x 3)) x"
+      env))
+  3)
+
+;; ── lambda ───────────────────────────────────────────────────────
+(scm-syn-test
+  "lambda: identity"
+  (scm-syn-eval "((lambda (x) x) 42)" (scm-syn-env))
+  42)
+(scm-syn-test
+  "lambda: arithmetic"
+  (scm-syn-eval "((lambda (x y) (+ x y)) 3 4)" (scm-syn-env))
+  7)
+(scm-syn-test
+  "lambda: zero args"
+  (scm-syn-eval "((lambda () 99))" (scm-syn-env))
+  99)
+(scm-syn-test
+  "lambda: multi-body"
+  (scm-syn-eval "((lambda (x) (define t (+ x 1)) (+ t t)) 5)" (scm-syn-env))
+  12)
+(scm-syn-test
+  "lambda: rest-arg as bare symbol"
+  (scm-syn-eval "((lambda args args) 1 2 3)" (scm-syn-env))
+  (list 1 2 3))
+
+;; ── closures ─────────────────────────────────────────────────────
+(scm-syn-test
+  "closure: captures binding"
+  (let
+    ((env (scm-syn-env)))
+    (scm-syn-eval-all
+      "(define (make-adder n) (lambda (x) (+ x n))) ((make-adder 10) 5)"
+      env))
+  15)
+(scm-syn-test
+  "closure: counter via set!"
+  (let
+    ((env (scm-syn-env)))
+    (scm-syn-eval-all
+      "(define (make-counter) (define n 0) (lambda () (set! n (+ n 1)) n)) (define c (make-counter)) (c) (c) (c)"
+      env))
+  3)
+(scm-syn-test
+  "closure: curried"
+  (let
+    ((env (scm-syn-env)))
+    (scm-syn-eval-all
+      "(define curry+ (lambda (a) (lambda (b) (lambda (c) (+ a (+ b c)))))) (((curry+ 1) 2) 3)"
+      env))
+  6)
+
+;; ── recursion ────────────────────────────────────────────────────
+(scm-syn-test
+  "recursive: factorial 5"
+  (let
+    ((env (scm-syn-env)))
+    (scm-syn-eval-all
+      "(define (fact n) (if (<= n 1) 1 (* n (fact (- n 1))))) (fact 5)"
+      env))
+  120)
+(scm-syn-test
+  "recursive: factorial 10"
+  (let
+    ((env (scm-syn-env)))
+    (scm-syn-eval-all
+      "(define (fact n) (if (<= n 1) 1 (* n (fact (- n 1))))) (fact 10)"
+      env))
+  3628800)
+(scm-syn-test
+  "recursive: list length"
+  (let
+    ((env (scm-syn-env)))
+    (scm-syn-eval-all
+      "(define (len xs) (if (= 0 (- 0 0)) (if (= xs (quote ())) 0 (+ 1 (len (cdr xs)))) 0)) (len '(a b c d))"
+      env))
+  4)
+
+;; ── quote vs eval distinction ────────────────────────────────────
+(scm-syn-test
+  "quote: list literal"
+  (scm-syn-eval "'(1 2 3)" (scm-syn-env))
+  (list 1 2 3))
+(scm-syn-test
+  "quote: nested"
+  (scm-syn-eval "'(a (b c) d)" (scm-syn-env))
+  (list "a" (list "b" "c") "d"))
+(scm-syn-test
+  "quote: symbol vs evaluated"
+  (let ((env (scm-syn-env))) (scm-syn-eval-all "(define x 42) 'x" env))
+  "x")
+
+;; ── let / let* ───────────────────────────────────────────────────
+(scm-syn-test "let: returns body"
+  (scm-syn-eval "(let ((x 5)) (+ x 1))" (scm-syn-env)) 6)
+(scm-syn-test "let: multiple bindings"
+  (scm-syn-eval "(let ((x 3) (y 4)) (+ x y))" (scm-syn-env)) 7)
+(scm-syn-test "let: parallel (RHS sees outer)"
+  (let ((env (scm-syn-env)))
+    (scm-syn-eval-all "(define x 1) (let ((x 10) (y x)) y)" env)) 1)
+(scm-syn-test "let: bindings don't leak"
+  (let ((env (scm-syn-env)))
+    (scm-syn-eval-all "(define x 1) (let ((x 99)) x) x" env)) 1)
+(scm-syn-test "let*: sequential"
+  (scm-syn-eval "(let* ((x 1) (y (+ x 1)) (z (+ y 1))) z)"
+                (scm-syn-env)) 3)
+(scm-syn-test "let*: shadow earlier"
+  (scm-syn-eval "(let* ((x 1) (x 2)) x)" (scm-syn-env)) 2)
+
+;; ── cond / when / unless ─────────────────────────────────────────
+(scm-syn-test "cond: first match"
+  (scm-syn-eval "(cond (#f 1) (#t 2) (#t 3))" (scm-syn-env)) 2)
+(scm-syn-test "cond: else"
+  (scm-syn-eval "(cond (#f 1) (else 99))" (scm-syn-env)) 99)
+(scm-syn-test "cond: untaken not evaluated"
+  (scm-syn-eval "(cond (#t 7) (nope ignored))" (scm-syn-env)) 7)
+(scm-syn-test "cond: no match returns nil"
+  (scm-syn-eval "(cond (#f 1) (#f 2))" (scm-syn-env)) nil)
+(scm-syn-test "cond: test-only clause"
+  (scm-syn-eval "(cond (42))" (scm-syn-env)) 42)
+(scm-syn-test "when: true"
+  (scm-syn-eval "(when #t 1 2 3)" (scm-syn-env)) 3)
+(scm-syn-test "when: false"
+  (scm-syn-eval "(when #f nope)" (scm-syn-env)) nil)
+(scm-syn-test "unless: false"
+  (scm-syn-eval "(unless #f 42)" (scm-syn-env)) 42)
+(scm-syn-test "unless: true"
+  (scm-syn-eval "(unless #t nope)" (scm-syn-env)) nil)
+
+;; ── and / or ─────────────────────────────────────────────────────
+(scm-syn-test "and: empty"
+  (scm-syn-eval "(and)" (scm-syn-env)) true)
+(scm-syn-test "and: all truthy returns last"
+  (scm-syn-eval "(and 1 2 3)" (scm-syn-env)) 3)
+(scm-syn-test "and: short-circuit on #f"
+  (scm-syn-eval "(and 1 #f nope)" (scm-syn-env)) false)
+(scm-syn-test "or: empty"
+  (scm-syn-eval "(or)" (scm-syn-env)) false)
+(scm-syn-test "or: first truthy"
+  (scm-syn-eval "(or #f 42 nope)" (scm-syn-env)) 42)
+(scm-syn-test "or: all #f"
+  (scm-syn-eval "(or #f #f #f)" (scm-syn-env)) false)
+
+(define scm-syn-tests-run! (fn () {:total (+ scm-syn-pass scm-syn-fail) :passed scm-syn-pass :failed scm-syn-fail :fails scm-syn-fails}))

lib/smalltalk/compare.sh

@@ -41,6 +41,7 @@ run_sx () {
 (load "lib/smalltalk/tokenizer.sx")
 (load "lib/smalltalk/parser.sx")
 (load "lib/smalltalk/runtime.sx")
+(load "lib/guest/reflective/env.sx")
 (load "lib/smalltalk/eval.sx")
 (epoch 2)
 (eval "(begin (st-bootstrap-classes!) (smalltalk-load \"Object subclass: #B instanceVariableNames: ''! !B methodsFor: 'x'! fib: n n < 2 ifTrue: [^ n]. ^ (self fib: n - 1) + (self fib: n - 2)! !\") (smalltalk-eval-program \"^ B new fib: 22\"))")

lib/smalltalk/eval.sx

@@ -60,16 +60,34 @@
   st-class-ref?
   (fn (v) (and (dict? v) (has-key? v :type) (= (get v :type) "st-class"))))
 
-;; Walk the frame chain looking for a local binding.
+;; Smalltalk-side adapter for lib/guest/reflective/env.sx. The
+;; Smalltalk frame carries language-specific metadata (:self,
+;; :method-class, :return-k, :active-cell) but the parent-walk for
+;; local-binding lookup is the same algorithm Kernel and Tcl use.
+;; Third consumer of the env kit; cfg routes through :locals and
+;; :parent and uses mutable dict-set! for binding.
+(define st-frame-cfg
+  {:bindings-of (fn (f) (get f :locals))
+   :parent-of   (fn (f) (get f :parent))
+   :extend      (fn (f) (st-make-frame nil nil f nil nil))
+   :bind!       (fn (f n v)
+                  (dict-set! (get f :locals) n v) f)
+   :env?        (fn (v) (and (dict? v) (dict? (get v :locals))))})
+
+;; Walk the frame chain looking for a local binding. Returns the
+;; Smalltalk-flavoured {:found :value :frame} shape callers expect;
+;; the parent-walk delegates to refl-env-find-frame-with.
 (define
   st-lookup-local
   (fn
     (frame name)
-    (cond
-      ((= frame nil) {:found false :value nil :frame nil})
-      ((has-key? (get frame :locals) name)
-        {:found true :value (get (get frame :locals) name) :frame frame})
-      (else (st-lookup-local (get frame :parent) name)))))
+    (let ((src (refl-env-find-frame-with st-frame-cfg frame name)))
+      (cond
+        ((nil? src) {:found false :value nil :frame nil})
+        (:else
+          {:found true
+           :value (get (get src :locals) name)
+           :frame src})))))
 
 ;; Walk the frame chain looking for the frame whose self has this ivar.
 (define

lib/smalltalk/test.sh

@@ -61,6 +61,7 @@ EPOCHS
 (epoch 3)
 (load "lib/smalltalk/runtime.sx")
 (epoch 4)
+(load "lib/guest/reflective/env.sx")
 (load "lib/smalltalk/eval.sx")
 (epoch 5)
 (load "lib/smalltalk/sunit.sx")
@@ -116,6 +117,7 @@ EPOCHS
 (epoch 3)
 (load "lib/smalltalk/runtime.sx")
 (epoch 4)
+(load "lib/guest/reflective/env.sx")
 (load "lib/smalltalk/eval.sx")
 (epoch 5)
 (load "lib/smalltalk/sunit.sx")

lib/tcl/conformance.sh

@@ -69,6 +69,7 @@ for tcl_file in "${TCL_FILES[@]}"; do
 (epoch 2)
 (load "lib/tcl/parser.sx")
 (epoch 3)
+(load "lib/guest/reflective/env.sx")
 (load "lib/tcl/runtime.sx")
 (epoch 4)
 (load "$helper")

lib/tcl/runtime.sx

@@ -1,25 +1,33 @@
 ; Tcl-on-SX runtime evaluator
 ; State: {:frame frame :commands cmd-table :result last-result :output accumulated-output}
-; Requires lib/fiber.sx to be loaded first (provides make-fiber, fiber-resume, fiber-done?)
+; Requires lib/fiber.sx and lib/guest/reflective/env.sx to be loaded first.
+;
+; Frames keep their Tcl-specific shape ({:level :locals :parent}) but
+; route lookup/bind through the shared reflective env kit via the
+; adapter cfg below — second consumer for that kit alongside Kernel.
 
 (define make-frame (fn (level parent) {:level level :locals {} :parent parent}))
 
-(define
-  frame-lookup
-  (fn
-    (frame name)
-    (if
-      (nil? frame)
-      nil
-      (let
-        ((val (get (get frame :locals) name)))
-        (if (nil? val) (frame-lookup (get frame :parent) name) val)))))
+; Tcl-side adapter for lib/guest/reflective/env.sx. Frames are
+; functionally updated (assoc returns a fresh dict), and lookup-miss
+; returns nil (Tcl convention) — the *-with kit honours both.
+(define tcl-frame-cfg
+  {:bindings-of (fn (f) (get f :locals))
+   :parent-of   (fn (f) (get f :parent))
+   :extend      (fn (f) (make-frame (+ (get f :level) 1) f))
+   :bind!       (fn (f n v) (assoc f :locals (assoc (get f :locals) n v)))
+   :env?        (fn (v)
+                  (and (dict? v)
+                       (number? (get v :level))
+                       (dict? (get v :locals))))})
 
-(define
-  frame-set-top
-  (fn
-    (frame name val)
-    (assoc frame :locals (assoc (get frame :locals) name val))))
+(define frame-lookup
+  (fn (frame name)
+    (refl-env-lookup-or-nil-with tcl-frame-cfg frame name)))
+
+(define frame-set-top
+  (fn (frame name val)
+    (refl-env-bind!-with tcl-frame-cfg frame name val)))
 
 (define make-tcl-interp (fn () {:result "" :output "" :code 0 :errorinfo "" :errorcode "" :frame (make-frame 0 nil) :frame-stack (list) :procs {} :commands {} :current-ns "::" :coro-yield-fn nil}))
 

lib/tcl/test.sh

@@ -42,6 +42,7 @@ cat > "$TMPFILE" << EPOCHS
 (load "lib/tcl/tests/parse.sx")
 (epoch 4)
 (load "lib/fiber.sx")
+(load "lib/guest/reflective/env.sx")
 (load "lib/tcl/runtime.sx")
 (epoch 5)
 (load "lib/tcl/tests/eval.sx")

plans/agent-briefings/smalltalk-loop.md

@@ -11,7 +11,7 @@ isolation: worktree
 
 ## Prompt
 
-You are the sole background agent working `/root/rose-ash/plans/smalltalk-on-sx.md`. Isolated worktree, forever, one commit per feature. Never push.
+You are the sole background agent working `/root/rose-ash/plans/smalltalk-on-sx.md`. Isolated worktree, forever, one commit per feature. Push to `origin/loops/smalltalk` after every commit.
 
 ## Restart baseline — check before iterating
 
@@ -43,7 +43,7 @@ Every iteration: implement → test → commit → tick `[ ]` → Progress log
 - **Shared-file issues** → plan's Blockers with minimal repro.
 - **Delimited continuations** are in `lib/callcc.sx` + `spec/evaluator.sx` Step 5. `sx_summarise` spec/evaluator.sx first — 2300+ lines.
 - **SX files:** `sx-tree` MCP tools ONLY. `sx_validate` after edits.
-- **Worktree:** commit locally. Never push. Never touch `main`.
+- **Worktree:** commit, then push to `origin/loops/smalltalk`. Never touch `main`.
 - **Commit granularity:** one feature per commit.
 - **Plan file:** update Progress log + tick boxes every commit.
 

plans/jit-cache-architecture.md

@@ -164,13 +164,22 @@ gets the same API for free.
 
 ## Rollout
 
-**Phase 1: Tiered compilation (1-2 days)**
-- Add `l_call_count` to lambda type
-- Wire counter increment in `cek_call_or_suspend`
-- Add `jit-set-threshold!` primitive
-- Default threshold = 1 (no change in behavior)
-- Bump default to 4 once test suite confirms stability
-- Verify: HS conformance full-suite run completes without JIT saturation
+**Phase 1: Tiered compilation — IMPLEMENTED (commit b9d63112)**
+- ✅ `l_call_count : int` field on lambda type (sx_types.ml)
+- ✅ Counter increment + threshold check in cek_call_or_suspend Lambda case (sx_vm.ml)
+- ✅ Module-level refs in sx_types: `jit_threshold` (default 4), `jit_compiled_count`,
+  `jit_skipped_count`, `jit_threshold_skipped_count`. Refs live in sx_types so
+  sx_primitives can read them without creating an import cycle.
+- ✅ Primitives: `jit-stats`, `jit-set-threshold!`, `jit-reset-counters!` (sx_primitives.ml)
+- Verified: 4771/1111 OCaml run_tests, identical to baseline — no regressions.
+
+**WASM rollout note:** The native binary has Phase 1 active. The browser
+WASM (`shared/static/wasm/sx_browser.bc.js`) needs to be rebuilt, but the
+new build uses a different value-wrapping ABI ({_type, __sx_handle} for
+numbers) incompatible with the current test runner (`tests/hs-run-filtered.js`).
+For now the test tree pins the pre-rewrite WASM. Resolving the ABI gap
+is a separate task — either update the test runner to unwrap, or expose
+a value-marshalling helper from the kernel.
 
 **Phase 2: LRU cache (3-5 days)**
 - Extract `Lambda.l_compiled` into central `sx_jit_cache.ml`

plans/kernel-on-sx.md

@@ -87,12 +87,12 @@ The whole interesting thing: there are no special forms hardcoded in the evaluat
 - [x] Bridge to SX's hygienic macro story; extends proposed `lib/guest/reflective/` with `$let` and `$define-in!` hygiene primitives.
 - [x] Tests: write an operative that introduces a binding and verify it doesn't shadow caller's same-named bindings.
 
-### Phase 7 — Propose `lib/guest/reflective/`  *[partial — pending second consumer]*
+### Phase 7 — Propose `lib/guest/reflective/`  *[env.sx EXTRACTED 2026-05-12; other five still pending]*
 - [x] Identified reusable env-reification + dispatch primitives across Phases 2–6. Consolidated API surface below as four candidate files: `env.sx`, `combiner.sx`, `evaluator.sx`, `hygiene.sx`.
-- [ ] Find a second consumer (Common-Lisp's macro-expansion evaluator? a metacircular Scheme variant? a future plan). Until this lands, extraction is blocked by the two-consumer rule.
-- [ ] Only extract once two consumers exist (per stratification rule). **Do not extract from this loop** — Kernel is one consumer; we need another before `lib/guest/reflective/` is real.
+- [x] Second consumer found for **`env.sx`**: Tcl's `uplevel`/`upvar` machinery (`lib/tcl/runtime.sx`). Same scope-chain semantics, divergent only in mutable-vs-functional update — bridged via adapter-cfg pattern from `lib/guest/match.sx`. Extraction landed on branch `lib/tcl/uplevel` (see `plans/lib-guest-reflective.md`).
+- [ ] Second consumers still needed for `combiner.sx`, `evaluator.sx`, `hygiene.sx`, `quoting.sx`, `short-circuit.sx` — all five wait for a language with operative/applicative semantics (Scheme, CL fexpr extension, Maru).
 
-**Phase 7 status:** the API surface is fully documented in the "Proposed `lib/guest/reflective/…` API" sections below. Candidate second consumers in priority order:
+**Phase 7 status (updated 2026-05-12):** `env.sx` has been extracted and is live at `lib/guest/reflective/env.sx` on branch `lib/tcl/uplevel`. Both consumers (Kernel and Tcl) pass their full test suites unchanged (Kernel 322/322, Tcl 427/427). The remaining five candidate files stay documented-only until their respective second consumers materialise. Candidate second consumers in priority order: Candidate second consumers in priority order:
 
 1. **A metacircular Scheme** — Scheme can reuse `env.sx` directly (same scope semantics), borrow `evaluator.sx`'s eval/make-env/current-env triple, and pattern-match the `hygiene.sx` story (Scheme has identical lexical scope). Would NOT need `combiner.sx` since Scheme has no applicative/operative split — that file stays Kernel-only until a third reflective-fexpr consumer materialises.
 2. **Common-Lisp's macro-expansion evaluator** — CL's `*macroexpand-hook*` and `compiler-let` machinery would consume `env.sx` (CL package envs map cleanly) and `evaluator.sx` (defmacro = an operative-like fexpr in expander phase). CL's symbol-stamping for hygienic macros could drive the deferred scope-set extension to `hygiene.sx`.

plans/lib-guest-reflective.md

@@ -0,0 +1,145 @@
+# lib/guest/reflective/ — first extraction kit, driven by Tcl uplevel as second consumer
+
+The `kernel-on-sx` loop accumulated six proposed `lib/guest/reflective/` files (`env.sx`, `combiner.sx`, `evaluator.sx`, `hygiene.sx`, `quoting.sx`, `short-circuit.sx`) but extraction was blocked on the two-consumer rule. This plan opens that block by selecting Tcl's `uplevel`/`upvar` machinery as the second consumer for the **`env.sx`** file specifically — the highest-fit candidate.
+
+Why Tcl/uplevel for *env*: both Kernel and Tcl implement first-class scope chains with recursive parent-walking lookup, and both expose those scopes to user code (Kernel via `get-current-environment`; Tcl via `uplevel`/`upvar`). The first extraction is the smallest plausible kit that both can credibly use.
+
+Why not the whole set in one go: the other five files (`combiner.sx`, `evaluator.sx`, `hygiene.sx`, `quoting.sx`, `short-circuit.sx`) need consumers that exhibit *operative/applicative semantics*, which Tcl lacks. They stay deferred until a Scheme or Maru port lands.
+
+## Discovery — current state, head-to-head
+
+```
+                  Kernel env                     Tcl frame
+─────────────────────────────────────────────────────────────────────
+shape             {:knl-tag :env                 {:level N
+                   :bindings DICT                 :locals DICT
+                   :parent ENV-OR-NIL}            :parent FRAME-OR-NIL}
+
+update model      MUTABLE (dict-set!)            FUNCTIONAL (assoc returns new)
+
+scope chain       parent pointer                 parent pointer
+                                                 + explicit :frame-stack
+                                                   on the interp
+
+construction      (kernel-make-env)              (make-frame LEVEL PARENT)
+                  (kernel-extend-env P)
+
+lookup            (kernel-env-lookup E N)        (frame-lookup F N)
+                  — raises on miss               — returns nil on miss
+
+bind              (kernel-env-bind! E N V)       (frame-set-top F N V)
+                  — mutates                      — returns new frame
+
+presence          (kernel-env-has? E N)          (frame-lookup F N) then nil-check
+
+call-stack walk   (nothing — only single chain)  (tcl-frame-nth STACK LEVEL)
+                                                 — indexes into :frame-stack
+
+variable alias    (nothing)                      (upvar-alias? V)
+                                                 — alias dict points at
+                                                   level + name in another frame
+```
+
+## The genuine overlap
+
+The recursive parent-walk is identical in spirit. Both languages need:
+
+1. A scope type with a *bindings dict* and *parent pointer*.
+2. A *lookup* that walks parents until a hit (or nil/raise on miss).
+3. A way to *extend* — push a fresh child frame.
+4. A way to *write a binding* in a chosen frame.
+
+The genuine divergence is *mutable vs functional update*. Tcl can't switch to mutable bindings without changing `frame-set-top`'s call sites (which return new interp state); Kernel can't switch to functional without rewriting `$define!` semantics (which mutates the dyn-env in place).
+
+## The proposed API — adapter-driven, like `match.sx`
+
+`lib/guest/match.sx` solves the same shape-divergence problem with a `cfg` adapter dict: the kit operates on a generic term representation, consumers pass callbacks that bridge their shape to it. The pattern works because the *algorithms* are language-agnostic; only the *data layout* differs.
+
+`lib/guest/reflective/env.sx` should follow the same pattern.
+
+```lisp
+;; Canonical wire shape (default):
+;;   {:refl-tag :env :bindings DICT :parent ENV-OR-NIL}
+;;
+;; Adapter cfg keys (for consumers with their own shape):
+;;   :bindings-of    — fn (scope) → DICT      ; access bindings dict
+;;   :parent-of      — fn (scope) → SCOPE-OR-NIL
+;;   :extend         — fn (scope) → SCOPE     ; child of scope
+;;   :bind!          — fn (scope name val) → scope   ; functional-or-mutable
+;;
+;; Default cfg (refl-default-cfg) implements the canonical wire shape
+;; with MUTABLE bindings (dict-set!). Tcl provides its own cfg with
+;; functional bindings and the level field preserved.
+
+(refl-make-env)                    ;; canonical, mutable
+(refl-extend-env PARENT)
+(refl-env-bind!   ENV NAME VAL)    ;; mutates; returns ENV
+(refl-env-has?    ENV NAME)
+(refl-env-lookup  ENV NAME)        ;; raises on miss
+(refl-env-lookup-or-nil ENV NAME)  ;; for guests that prefer nil
+
+;; With explicit cfg — for consumers with their own shape:
+(refl-env-lookup-with CFG SCOPE NAME)
+(refl-env-bind!-with  CFG SCOPE NAME VAL)
+(refl-env-extend-with CFG SCOPE)
+```
+
+The two consumer migrations:
+
+- **Kernel**: drops `kernel-make-env`, `kernel-extend-env`, `kernel-env-bind!`, `kernel-env-has?`, `kernel-env-lookup`. Replaces with `refl-*` calls on the canonical shape. Rename `:knl-tag` → `:refl-tag`. No semantic change.
+- **Tcl**: keeps its `{:level :locals :parent}` shape but defines a Tcl-cfg adapter. `frame-lookup` becomes `(refl-env-lookup-with tcl-frame-cfg frame name)`. `frame-set-top` stays where it is — Tcl needs functional updates for the assoc-back-to-interp chain. The kit accommodates both, just like `match.sx` accommodates miniKanren's wire shape and Haskell's term shape.
+
+## Roadmap
+
+### Phase 1 — Skeleton + Kernel migration  *[DONE 2026-05-12]*
+
+- [x] Create `lib/guest/reflective/env.sx` with the canonical wire shape and mutable defaults.
+- [x] Migrate `lib/kernel/eval.sx` to use `refl-make-env` / `refl-extend-env` / `refl-env-*`. Rename `:knl-tag` → `:refl-tag` in env values only (operatives/applicatives keep their own tags for now).
+- [x] All 322 Kernel tests stay green.
+
+### Phase 2 — Tcl adapter  *[DONE 2026-05-12]*
+
+- [x] Add `tcl-frame-cfg` in `lib/tcl/runtime.sx`. `frame-lookup` and `frame-set-top` now delegate to `refl-env-lookup-or-nil-with` / `refl-env-bind!-with`. Tcl's `{:level :locals :parent}` shape unchanged.
+- [x] Tcl test suite green (427/427).
+
+### Phase 3 — Documentation + cross-reference  *[DONE 2026-05-12]*
+
+- [x] Update `plans/kernel-on-sx.md` to mark Phase 7's *env.sx* extraction as DONE (one of six). Other five blocked.
+- [x] `lib/guest/reflective/env.sx` header docstring already lists both consumers and links back to this plan.
+
+### Phase 4 — Quick wins identified along the way
+
+- [ ] Tcl's `tcl-frame-nth` (index into call stack by level) is the start of a *stack-frame protocol* — separate from the scope-chain protocol. Tcl needs it; Kernel doesn't. Document as "language-specific extension on top of the shared kit"; consider extracting later if a third consumer (Scheme `call-with-values`, CL `compiler-let`) needs frame-level indexing.
+
+## Non-goals
+
+- **Do not extract `combiner.sx`, `evaluator.sx`, `hygiene.sx`, `quoting.sx`, or `short-circuit.sx`** in this branch. Tcl doesn't have operatives/applicatives; the two-consumer rule isn't satisfied for those files. They stay documented-only in `plans/kernel-on-sx.md` until a Scheme/Maru/CL-fexpr consumer arrives.
+- **Do not change Tcl's update model to mutable**. The functional `frame-set-top` is structural — it's how Tcl threads the interp through `tcl-var-set`/`tcl-var-get`. Don't break it.
+- **Do not unify the env-lookup error semantics**. Kernel raises; Tcl returns nil. The kit offers both (`refl-env-lookup` and `refl-env-lookup-or-nil`) and consumers pick.
+
+## Validation criteria
+
+The extraction is real iff:
+
+1. Both consumers compile and pass their full test suites unchanged.
+2. The shared `env.sx` file is ≥80 LoC (substantial enough to be worth sharing) and ≤200 LoC (small enough that the cfg adapter pattern doesn't become its own framework).
+3. A third consumer in the future can adopt the kit by writing only the cfg dict — no algorithm changes to `env.sx`.
+
+## Outcome (2026-05-12)
+
+Three commits on `lib/tcl/uplevel`:
+
+1. Plan committed.
+2. **`reflective: extract env.sx + migrate Kernel — 322 tests green`** — kit landed; Kernel's env block collapsed from ~30 lines to 6 thin wrappers (`kernel-env? = refl-env?` etc.). Envs now carry `:refl-tag :env`. All 7 Kernel suites unchanged.
+3. **`reflective: Tcl adapter cfg — second consumer wired, 427+322 tests green`** — `tcl-frame-cfg` defined, `frame-lookup`/`frame-set-top` delegate to the kit. Tcl's frame shape unchanged. Functional update preserved.
+
+**File stats:** `lib/guest/reflective/env.sx` is 124 lines, 13 forms. Within the 80–200 LoC validation bound. Adapter-cfg pattern proven to bridge mutable-canonical (Kernel) and functional-frame (Tcl) wire shapes via a single ~7-line cfg dict per consumer.
+
+**Third-consumer test:** any future guest can adopt the kit by writing its own cfg with five keys (`:bindings-of`, `:parent-of`, `:extend`, `:bind!`, `:env?`) — no changes to `env.sx`. The shape-divergence problem is solved by parameterisation, not by forcing both consumers onto one wire shape.
+
+## References
+
+- `plans/kernel-on-sx.md` — the kernel-on-sx loop's chisel notes; the six candidate API surfaces are documented there.
+- `lib/guest/match.sx` — precedent for the adapter-cfg extraction pattern.
+- `lib/tcl/runtime.sx` lines 5–22 (`make-frame`, `frame-lookup`, `frame-set-top`) — the Tcl consumer's current implementation.
+- `lib/kernel/eval.sx` lines 39–82 (env block) — the Kernel consumer's current implementation.

plans/minikanren-deferred.md

@@ -0,0 +1,216 @@
+# miniKanren-on-SX: deferred work
+
+The main plan (`plans/minikanren-on-sx.md`) carries Phases 1–7 through the
+naive-tabling milestone. This file collects the four pieces left on the
+shelf, with enough scope and design notes to drive a follow-up loop.
+
+Branch convention: keep the same `loops/minikanren` worktree; commit and
+push to `origin/loops/minikanren`. Squash-merge to `architecture` only
+when each numbered piece is shipped + tests green.
+
+Cumulative test count snapshot at squash-merge: **644** across
+**71 test files**. Every change below should grow the number, not break
+existing tests.
+
+## The four pieces
+
+### Piece A — Phase 7 SLG (cyclic patho, mutual recursion, fixed-point iteration)
+
+**Problem.** Naive tabling drains the answer stream eagerly, then caches.
+Recursive tabled calls with the SAME ground key see an empty cache (the
+in-progress entry never exists), so they recurse and the host
+overflows. Fibonacci works only because each recursive call has a
+*different* key; cyclic `patho` and any genuinely self-recursive tabled
+predicate diverge.
+
+**Approach** — a small subset of SLG / OLDT resolution, enough to handle
+the demos in the brief.
+
+1. **In-progress sentinel.** When a tabled call `T(args)` starts, store
+   `(:in-progress nil)` under its key. Recursive calls into `T(args)`
+   from inside its own computation see the sentinel and return only
+   the answers accumulated so far (initially empty).
+2. **Answer accumulator.** As each new answer is found, push it into
+   the cache entry: `(:in-progress accumulated-answers)`. After a
+   cycling caller returns, the outer continuation can re-consult the
+   updated cache.
+3. **Fixed-point iteration.** The driver repeatedly re-runs the goal
+   until no new answers appear in a full pass, then transitions the
+   cache from `:in-progress` to `:done`.
+4. **Subgoal table.** Track (subgoal, last-seen-cache-version) per
+   subscriber so each consumer only re-reads what it hasn't seen.
+
+**Suggested artefacts.**
+- `lib/minikanren/tabling-slg.sx` — new module with `table-slg-2`
+  (parallel to `table-2` from naive tabling). Keep `table-2` working
+  unchanged so Fibonacci/Ackermann don't regress.
+- `lib/minikanren/tests/cyclic-graph-tabled.sx` — the canonical demo:
+  two-cycle `patho` from a→b→a→b plus a→b→c. With SLG, `(run* q
+  (tab-patho :a :c q))` returns the single shortest path, not divergence.
+- `lib/minikanren/tests/mutual-recursion.sx` — even/odd via mutual
+  recursion (`even-o n` ↔ `odd-o (n-1)`), tabled at both names.
+
+**Reference reading.**
+- TRS chapter on tabling.
+- "Tabled Logic Programming" — Sagonas & Swift (the XSB / SLG paper).
+- core.logic's `tabled` macro for an SX-dialect-friendly precedent.
+
+**Risk.** This is the brief's "research-grade complexity, not a
+one-iteration item". Plan for 4–6 commits: in-progress sentinel,
+answer accumulator, fixed-point driver, then one demo per commit.
+
+### Piece B — Phase 6 polish: bounds-consistency for `fd-plus` / `fd-times`
+
+**Problem.** Current `fd-plus-prop` and `fd-times-prop` propagate only
+when two of three operands walk to ground numbers. When all three are
+domain-bounded vars, the propagator returns `s` unchanged — search has
+to label down to ground before any narrowing happens.
+
+**Approach** — narrow domains via interval reasoning even when no operand
+is ground.
+
+For `(fd-plus x y z)` with bounded x, y, z:
+- `x ∈ [z.min − y.max .. z.max − y.min]`
+- `y ∈ [z.min − x.max .. z.max − x.min]`
+- `z ∈ [x.min + y.min .. x.max + y.max]`
+
+For `(fd-times x y z)`: same shape, but with multiplication; need to
+handle sign cases (negative domain ranges) and the divisor-when-not-zero
+constraint already in place.
+
+**Suggested artefacts.**
+- Patch `fd-plus-prop` and `fd-times-prop` in `lib/minikanren/clpfd.sx`
+  with new `:else` branches that compute new domain bounds and call
+  `fd-set-domain` for each var.
+- New tests in `lib/minikanren/tests/clpfd-plus.sx` /
+  `clpfd-times.sx` exercising the all-domain case: two domain-bounded
+  vars in the body of a goal, with no labelling, after which their
+  domains have narrowed.
+- A demo: cryptarithmetic puzzle (see Piece D) using bounds
+  consistency to avoid labelling explosion.
+
+**Risk.** Low. The math is well-known; just careful min/max arithmetic
+and watch for edge cases (empty domain after narrowing).
+
+### Piece C — `=/=` disequality with constraint store
+
+**Problem.** `nafc` is sound only on ground args; `fd-neq` only on FD
+domains. There is no general-purpose Prolog-style structural
+disequality `=/=` that works on logic terms.
+
+**Approach.** Generalise the FD constraint store to a uniform
+"constraint store" that carries:
+- domain map (existing)
+- *pending disequalities* — a list of `(u v)` pairs that must remain
+  non-unifiable under any future extension.
+
+After every `==` / `mk-unify`, re-check each pending disequality:
+- If `(u v)` are now unifiable, fail.
+- If they're now structurally distinct (no shared substitution can
+  unify), drop from the store (the constraint is satisfied).
+- Otherwise leave in store.
+
+**Where it bites.** The kernel currently uses `mk-unify` everywhere.
+Either:
+1. Replace `mk-unify` with a constraint-aware wrapper everywhere
+   (intrusive, but principled).
+2. Keep `mk-unify` for goals that don't use `=/=`, and provide a
+   parallel `==-cs` / `=/=-cs` pair plus an alternative `run*-cs`
+   driver that fires the constraint check after each binding.
+
+Option 2 mirrors the `fd-fire-store` pattern and stays out of the
+common path.
+
+**Suggested artefacts.**
+- `lib/minikanren/diseq.sx` — disequality store on top of the
+  existing `_fd` reserved key (re-using the constraint list, just
+  with disequality-shaped closures instead of FD propagators).
+- `=/=` goal that posts a disequality and immediately checks it.
+- `=/=-test` integration: rewrite a few Phase 5 puzzles using `=/=`
+  instead of `nafc + ==`.
+- Tests covering: ground-pair fail, partial-pair satisfied later by
+  binding, partial-pair *contradicted* later by binding.
+
+**Risk.** Medium. The hard cases are *eventual* unifiability — a
+disequality `(=/= (cons a 1) (cons 2 b))` should hold until both `a`
+gets bound to `2` and `b` gets bound to `1`. Implementations like
+core.logic's encode this as a list of "violating bindings" the
+disequality remembers.
+
+### Piece D — Bigger CLP(FD) demos: send-more-money + Sudoku 4×4
+
+**Problem.** The current N-queens demo only verifies the constraint
+chain end-to-end. The brief's full Phase 6 list includes
+"send-more-money, N-queens with CLP(FD), map coloring,
+cryptarithmetic" — most of which exercise *more* than just `fd-neq +
+fd-distinct`.
+
+**Approach.** Two concrete puzzles that both stress
+bounds-consistency (Piece B) once it lands:
+
+#### send-more-money
+
+```
+  S E N D
++ M O R E
+---------
+M O N E Y
+```
+
+8 distinct digits ∈ {0..9}, S ≠ 0, M ≠ 0. Encoded as a sum-of-digits
+equation using `fd-plus` + carry chains.
+
+Without Piece B (bounds-consistency), the search labels every digit
+combination upfront — slow but tractable on a fast machine. With
+Piece B, the impossible high-digit cases prune early.
+
+Test: a single solution `(9 5 6 7 1 0 8 2)`.
+
+#### Sudoku 4×4
+
+Easier than 9×9 but exercises the full pattern:
+- 16 cells, each ∈ {1..4}
+- 4 rows, 4 cols, 4 2×2 boxes — 12 `fd-distinct` constraints
+- Some cells fixed as clues
+
+A small solver should handle 4×4 in well under a second once
+bounds-consistency narrows columns / boxes after each label step.
+
+**Suggested artefacts.**
+- `lib/minikanren/tests/send-more-money.sx` — single-solution test.
+- `lib/minikanren/tests/sudoku-4x4.sx` — at least three cluesets:
+  unique solution, multiple solutions, no solution.
+- Optional: `lib/minikanren/sudoku.sx` with a parameterised
+  `sudoku-n` for both 4×4 and a 9×9 stress test.
+
+**Risk.** Low–medium for 4×4 + send-more-money once Piece B lands.
+9×9 Sudoku is a stretch; treat it as a stretch goal once the smaller
+demos are green.
+
+## Suggested ordering
+
+1. **Piece B first** (bounds-consistency for `fd-plus` / `fd-times`).
+   Self-contained, low-risk, and unlocks Piece D's harder puzzles.
+2. **Piece D** (the two demos). Validates Piece B with concrete
+   puzzles. Doubles as the brief's missing canary tests.
+3. **Piece C** (`=/=`). Independent track; once shipped, refactor the
+   pet/diff puzzles in Phase 5 to use it instead of nafc.
+4. **Piece A** (SLG tabling). Last because it's the highest-risk
+   piece; do it when the rest of the library is stable so regressions
+   are easy to spot.
+
+## Operating ground rules (carry over from the original brief)
+
+- **Scope:** `lib/minikanren/**` and the two plan files (this one and
+  the original).
+- **Commit cadence:** one feature per commit. Short factual messages
+  (`mk: piece B — bounds-consistency for fd-plus`).
+- **Plan updates:** tick boxes here as pieces land; mirror status in
+  `plans/minikanren-on-sx.md` Roadmap.
+- **Test discipline:** every commit ends with the cumulative count
+  green. No-regression rule from the original brief still applies.
+- **`sx-tree` MCP only** for `.sx` edits. `sx_validate` after every
+  structural edit.
+- **Pushing:** `origin/loops/minikanren` only. Never `main`. Squash to
+  `architecture` only with explicit user permission, as we did for
+  the v1 merge.

plans/scheme-on-sx.md

@@ -0,0 +1,191 @@
+# Scheme-on-SX: the reflective-kit second-consumer port
+
+The kernel-on-sx loop documented six reflective API candidates; two are now live (`env.sx`, `class-chain.sx`). Three more — `evaluator.sx`, `hygiene.sx`, `quoting.sx` — wait on a guest with operative-free lexical scope, hygienic syntax-transformer infrastructure, and quasiquote. **Scheme is exactly that guest.**
+
+A correct R7RS-small implementation acts as second consumer for those three kits in one stroke. It also confirms a third independent consumer for `env.sx` (after Kernel + Tcl + Smalltalk), and a candidate fourth consumer for `class-chain.sx` (Scheme's record types have parent fields — though OO is non-core in Scheme so the fit is weaker).
+
+## Strategic note on `combiner.sx`
+
+Scheme has *no fexprs*. `combiner.sx`'s applicative/operative split is Kernel-specific machinery. **Scheme is not a second consumer for `combiner.sx`** — that file stays Kernel-only until a Maru, Klisp, or CL-fexpr port arrives. The current session's earlier claim that Scheme "unlocks four more reflective kits" was over-counted; the correct number is **three**.
+
+## Scope decisions
+
+- **Target dialect:** R7RS-small. Source-only — no images, no FFI, no C extensions, no JIT.
+- **Numbers:** integers + floats. Rationals optional (defer to phase N+1). Complex out.
+- **Tail-call optimisation:** required. Implemented via the existing SX CEK machinery — call recursion in the evaluator uses iterative `cek-call` rather than host recursion.
+- **Continuations:** `call/cc` required for R7RS. Use SX's `call/cc` primitive directly.
+- **Hygienic macros:** `syntax-rules` required. `syntax-case` deferred.
+- **Char/string semantics:** Unicode codepoints; surface API matches R7RS section 6.
+- **I/O:** minimal stub (`display`, `write`, `newline`, `read`) on SX's IO surface.
+- **`define-library`:** required for module testing; implementation reuses SX's `define-library` if it's exposed, else hand-rolls a flat module registry.
+
+## Architecture sketch
+
+```
+lib/scheme/parser.sx     — reader: numbers, strings, symbols, booleans,
+                            chars #\c, vectors #(...), dotted-pairs (a . b),
+                            quasi-quote sugar, datum comments #;, block
+                            comments #| ... |#
+
+lib/scheme/eval.sx       — eval-expr ENV: walks AST. Symbols → env-lookup.
+                            Lists → look up head; if syntactic operator
+                            (if/lambda/define/set!/quote/quasiquote/
+                             let/let*/letrec/begin/cond/case/and/or/when/
+                             unless/do), dispatch to native handler. Else
+                            apply combiner (always applicative).
+
+                          ENV is `lib/guest/reflective/env.sx` directly
+                          — Scheme is the third consumer for env.sx with
+                          NO adapter cfg (canonical wire shape).
+
+lib/scheme/runtime.sx    — Standard environment, primitives, R7RS base.
+                            Variadic arithmetic, list ops, string ops,
+                            char ops, vector ops, define-record-type,
+                            syntax-rules, etc.
+
+lib/scheme/tests/        — Standard pattern: parse, eval, lambda+closure,
+                            macros (syntax-rules), call/cc, define-library,
+                            classic programs (factorial, Y, tree-walking,
+                            named let, do-loop), R7RS conformance subset.
+```
+
+## Roadmap
+
+### Phase 1 — Parser
+- [ ] Reader for R7RS lexical syntax: integers, floats, strings (with escapes), symbols (extended-identifier-character set), booleans `#t`/`#f`/`#true`/`#false`, characters `#\c` `#\space` `#\newline`, vectors `#(...)`, dotted pairs `(a . b)`, quote/quasiquote/unquote/unquote-splicing sugar (same reader macros as Kernel).
+- [ ] Datum comments `#;<datum>` (skip one whole expression).
+- [ ] Block comments `#| ... |#` (nestable).
+- [ ] Tests in `lib/scheme/tests/parse.sx`.
+
+### Phase 2 — Evaluator + env
+- [ ] `scheme-eval EXPR ENV` — primary entry, uses `lib/guest/reflective/env.sx` directly as the canonical scope chain. **Third consumer for env.sx.**
+- [ ] Self-evaluating: numbers, booleans, strings, chars, vectors.
+- [ ] Symbol lookup → `refl-env-lookup-with`.
+- [ ] List → look up head; syntactic operators dispatch natively; otherwise applicative call with evaluated args.
+- [ ] Tests in `lib/scheme/tests/eval.sx`.
+
+### Phase 3 — Syntactic operators
+- [ ] `if`, `quote`, `set!`, `define` (top-level + internal).
+- [ ] `lambda` — fixed-arity, rest-arg via dot, multi-body via implicit `begin`.
+- [ ] `let`, `let*`, `letrec`, `letrec*` — including named-let.
+- [ ] `begin` — implicit + explicit.
+- [ ] `cond`, `case`, `when`, `unless`, `and`, `or`, `do`.
+- [ ] Tests for each.
+
+### Phase 4 — Standard environment
+- [ ] Variadic `+ - * /` and chained comparison.
+- [ ] Type predicates (R7RS `number?`, `pair?`, `null?`, `symbol?`, `string?`, `procedure?`, `vector?`, `char?`, `boolean?`).
+- [ ] List ops: `cons car cdr caar cadr ... cddddr` (or just a subset), `list length reverse append map filter fold-left fold-right for-each`.
+- [ ] String ops: `string-length string-ref substring string-append string=? string<? char->integer integer->char`.
+- [ ] Char ops: `char->integer integer->char char-alphabetic? char-numeric?` etc.
+- [ ] Vector ops: `vector make-vector vector-length vector-ref vector-set! vector->list list->vector`.
+- [ ] I/O: `display write newline read`.
+- [ ] Numerical: `abs floor ceiling round truncate min max modulo quotient remainder gcd lcm expt`.
+- [ ] Classic programs: factorial, fib, list reversal, tree map.
+
+### Phase 5 — call/cc + dynamic-wind
+- [ ] `call-with-current-continuation` / `call/cc`.
+- [ ] `dynamic-wind`.
+- [ ] `with-exception-handler`, `raise`, `error`.
+- [ ] Tests: escape continuations, multi-shot via call/cc (chosen via host SX `call/cc`).
+
+### Phase 6 — `syntax-rules` + hygiene
+- [ ] `define-syntax`, `let-syntax`, `letrec-syntax`.
+- [ ] `syntax-rules` pattern matching, ellipsis, template instantiation.
+- [ ] Hygiene: scope-set / lifted-symbol implementation. **Second consumer for `lib/guest/reflective/hygiene.sx` extraction once that kit's API surface stabilises.**
+- [ ] Tests: hygienic identifier capture, ellipsis patterns, recursive macros.
+
+### Phase 7 — Reflection: `eval`, `interaction-environment`, etc.
+- [ ] `eval EXPR ENV` — applicative form of the evaluator. **Second consumer for `lib/guest/reflective/evaluator.sx` extraction.**
+- [ ] `interaction-environment`, `null-environment`, `scheme-report-environment`.
+- [ ] `environment?` predicate.
+
+### Phase 8 — `define-library` + module hygiene
+- [ ] `define-library`, `import`, `export`.
+- [ ] `cond-expand` for feature-flag conditionals.
+- [ ] Tests: cross-library imports, identifier renaming.
+
+### Phase 9 — Records
+- [ ] `define-record-type` with constructor/predicate/accessors/mutators.
+- [ ] Tests: typical record idioms.
+
+### Phase 10 — Quasiquote runtime
+- [ ] Backquote walker with depth tracking. **Second consumer for `lib/guest/reflective/quoting.sx` extraction.**
+- [ ] Tests including nested quasiquote.
+
+### Phase 11 — Conformance + scoreboard
+- [ ] Curated R7RS test slice (Chibi, Larceny, or hand-picked).
+- [ ] `lib/scheme/conformance.sh` + scoreboard.
+- [ ] Drive conformance toward 100% on chosen slice.
+
+## Reflective kit consumption — explicit mapping
+
+| Kit | When it lands | How Scheme uses it |
+|-----|--------------|-------------------|
+| `lib/guest/reflective/env.sx` | Phase 2 | Direct — canonical wire shape, no cfg needed. Third consumer. |
+| `lib/guest/reflective/evaluator.sx` | Phase 7 (will trigger the extraction) | Scheme's `eval`/`interaction-environment`/`null-environment` mirror the proposed `refl-eval`/`refl-make-environment`/`refl-current-env` triple. Second consumer → extraction unblocked. |
+| `lib/guest/reflective/hygiene.sx` | Phase 6 | Scheme's hygienic `syntax-rules` is the canonical implementation of scope sets / lifted symbols. Second consumer for the deferred Shutt-style hygiene work — Scheme's hygiene goes BEYOND Kernel's by-default-static-env-extension into proper scope-set lifting. Drives the deferred research-grade kit. |
+| `lib/guest/reflective/quoting.sx` | Phase 10 | Scheme's backquote walker is structurally identical to Kernel's `knl-quasi-walk`, with depth tracking added. Second consumer → extraction unblocked. |
+| `lib/guest/reflective/combiner.sx` | NEVER (no fexprs) | Not applicable. Stays Kernel-only until a fexpr-having consumer arrives. |
+| `lib/guest/reflective/short-circuit.sx` | Possibly Phase 3 | Scheme's `and`/`or` are syntactic, not operative; could be second consumer but adapter would need to bridge "macro that short-circuits" vs "operative that short-circuits". Marginal. |
+
+## Ground rules
+
+- **Scope:** only `lib/scheme/**` and `plans/scheme-on-sx.md` and `lib/guest/reflective/**` (for extraction work). Don't edit `spec/`, `hosts/`, `shared/`, or other `lib/<lang>/` directories.
+- **Consume:** `lib/guest/lex.sx` (character predicates), `lib/guest/reflective/env.sx` (scope chain), eventually `evaluator.sx`/`hygiene.sx`/`quoting.sx` once extracted with Scheme as second consumer.
+- **Commits:** one feature per commit. Short factual messages.
+- **Tests:** every phase ends with a test file. Conformance scoreboard at the end.
+- **Branch:** `loops/scheme`. Worktree pattern (already set up at `/root/rose-ash-loops/scheme`).
+- **Substrate gaps:** filed to `sx-improvements.md`, not fixed in this loop.
+
+## References
+
+- R7RS-small: https://small.r7rs.org/attachment/r7rs.pdf
+- Chibi Scheme — a small, readable R7RS implementation.
+- Dybvig, "Three Implementation Models for Scheme" — for the hygiene story.
+- Existing kernel-on-sx code in `lib/kernel/` — much of the parser, evaluator structure, and env handling carries over near-verbatim because Kernel and Scheme share lexical scope.
+
+## Progress log
+
+- 2026-05-14 — **Phases 1, 2, 3, 3.5, 4, 5abc, 6ab, 7, 8, 9, 10, 11 landed in one loop session.** 296 Scheme tests across 9 suites; ~1830 LoC of substrate. Test runner + scoreboard at `lib/scheme/test.sh` and `lib/scheme/scoreboard.md`. Three reflective kits unlocked: `env.sx` extracted directly as third consumer, `evaluator.sx` and `quoting.sx` second-consumer-ready for the kit-extraction commits (kit code is documented in `plans/kernel-on-sx.md`; Scheme consumer code is in place).
+
+### Phase-by-phase outcomes
+
+- Phase 1 (Parser, 62 tests): R7RS lexical syntax with reader macros, three comment flavours (`;`, `#;`, `#| |#`).
+- Phase 2 (Eval + env third-consumer, 23 tests): `scheme-make-env` etc. are thin aliases for `refl-env-*` from `lib/guest/reflective/env.sx`. No adapter cfg needed — Scheme uses the canonical wire shape directly.
+- Phase 3 (if/define/set!/begin/lambda + closures, 24 tests): factorial 10 → 3628800, counter via closed-over `set!`, curried lambda.
+- Phase 3.5 (let/let*/cond/when/unless/and/or, 21 tests).
+- Phase 4 (standard env + set! bugfix, 82 tests): variadic arithmetic, type predicates, list/string/char/vector ops, higher-order combinators. **Found and fixed an SX cond multi-expression branch bug** affecting set!. Bugfix unblocked 4 silently-failing tests in Phase 3.
+- Phase 5a (call/cc, 8 tests): single-shot escape continuations.
+- Phase 5b (raise/guard/with-exception-handler/error, 12 tests): catch-once-then-rehandle-outside pattern avoids handler-self-raise loops.
+- Phase 5c (dynamic-wind, 5 tests): basic before-thunk-after with raise propagation. call/cc-escape tracking deferred.
+- Phase 6a (define-syntax + syntax-rules, 12 tests): pattern matching with literals + pattern variables + list structure; template substitution.
+- Phase 6b (syntax-rules ellipsis, 8 tests): tail-rest single-variable form. `(my-and 1 2 3)` etc. work.
+- Phase 7 (eval / interaction-environment, 13 tests): **second consumer for evaluator.sx**. `interaction-environment` closes over the env being built, so user-side defines via `(eval ... ie)` persist across calls.
+- Phase 8 (define-library + import, 7 tests): minimal module system. Private definitions stay in library env; only exports are visible after import.
+- Phase 9 (define-record-type, 9 tests): tagged-dict records with optional mutators.
+- Phase 10 (quasiquote runtime, 10 tests): **second consumer for quoting.sx**. Identical algorithm to Kernel's `knl-quasi-walk` — universal across reflective Lisps.
+- Phase 11 (test.sh + scoreboard): single-process aggregating runner, scoreboard markdown.
+
+### Deferred phases
+
+- **Phase 6c — full hygiene**. Dybvig-style scope-sets / lifted-symbol algorithm. Would be the second consumer for the deferred `lib/guest/reflective/hygiene.sx`. Current macros work for common patterns but don't prevent introduced-binding capture. Research-grade work; warrants its own loop iteration.
+- **Nested quasiquote depth tracking**.
+- **R7RS module rich features** (`cond-expand`, `include`, import sets like `only`/`except`/`prefix`/`rename`).
+- **Dotted-pair `(a b . rest)` parser syntax** + lambda rest-args.
+- **Full call/cc + dynamic-wind interaction**: dynamic-extent re-entry/re-exit tracking.
+
+### Chisel ledger update
+
+This Scheme port satisfies the two-consumer rule for **three** reflective kits documented in the kernel-on-sx loop:
+
+| Kit | Status |
+|-----|--------|
+| `env.sx` | Extracted — Scheme is the third consumer (after Kernel + Tcl/Smalltalk), uses the canonical shape directly with no cfg |
+| `evaluator.sx` | Second consumer ready — Scheme `eval`/`interaction-environment`/`null-environment`/`scheme-report-environment` mirror the proposed `refl-eval`/`refl-current-env`/`refl-make-environment` triple |
+| `quoting.sx` | Second consumer ready — Scheme `scm-quasi-walk` is structurally identical to Kernel's `knl-quasi-walk`; the only difference is the unquote keyword names (cfg parameterisation) |
+| `hygiene.sx` | Still awaiting (needs Phase 6c) |
+| `combiner.sx` | N/A — Scheme has no fexprs |
+| `short-circuit.sx` | N/A — Scheme `and`/`or` are syntactic, not operative |
+
+The kit-extraction commits themselves are follow-on work; this Scheme port is the consumer-side foundation.