js-on-sx: fn.length/.name/.call/.apply/.bind as properties (not just methods)

js-get-prop on a function receiver only routed .prototype before; now also
handles .name (returns ''), .length (returns 0), and .call/.apply/.bind
as bound function references.

Previously Math.abs.length crashed with 'TypeError: length is not a function'.
Similarly for arr.sort.call which is a common test262 pattern.

Pass rate stable at 514/516.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lib/js/runtime.sx

@@ -109,6 +109,19 @@
       ((= key "length") 0)
       (else :js-undefined))))
 
+(define
+  js-invoke-function-bound
+  (fn
+    (recv key)
+    (cond
+      ((= key "call")
+        (fn (&rest args) (js-invoke-function-method recv "call" args)))
+      ((= key "apply")
+        (fn (&rest args) (js-invoke-function-method recv "apply" args)))
+      ((= key "bind")
+        (fn (&rest args) (js-invoke-function-method recv "bind" args)))
+      (else :js-undefined))))
+
 (define
   js-invoke-number-method
   (fn
@@ -170,6 +183,13 @@
             (str "-" (js-num-to-str-radix-rec (- 0 int-n) radix ""))
             (js-num-to-str-radix-rec int-n radix "")))))))
 
+;; parse a decimal number from a trimmed non-empty string.
+;;   s      — source
+;;   i      — cursor
+;;   acc    — integer part so far (or total for decimals)
+;;   sign   — 1 or -1
+;;   frac?  — are we past the decimal point
+;;   fdiv   — divisor used to scale fraction digits (only if frac?)
 (define
   js-num-to-str-radix-rec
   (fn
@@ -181,13 +201,6 @@
         ((d (mod n radix)) (rest (js-math-trunc (/ n radix))))
         (js-num-to-str-radix-rec rest radix (str (js-digit-char d) acc))))))
 
-;; parse a decimal number from a trimmed non-empty string.
-;;   s      — source
-;;   i      — cursor
-;;   acc    — integer part so far (or total for decimals)
-;;   sign   — 1 or -1
-;;   frac?  — are we past the decimal point
-;;   fdiv   — divisor used to scale fraction digits (only if frac?)
 (define
   js-digit-char
   (fn
@@ -220,16 +233,19 @@
                   "."
                   (js-pad-int-str (js-to-string (js-math-trunc frac-abs)) d))))))))))
 
+;; ── String coercion (ToString) ────────────────────────────────────
+
 (define
   js-pow-int
   (fn (b e) (if (<= e 0) 1 (* b (js-pow-int b (- e 1))))))
 
-;; ── String coercion (ToString) ────────────────────────────────────
-
 (define
   js-pad-int-str
   (fn (s n) (if (>= (len s) n) s (js-pad-int-str (str "0" s) n))))
 
+;; ── Arithmetic (JS rules) ─────────────────────────────────────────
+
+;; JS `+`: if either operand is a string → string concat, else numeric.
 (define
   js-apply-fn
   (fn
@@ -261,9 +277,6 @@
             (nth args 5)))
         (else (apply callable args))))))
 
-;; ── Arithmetic (JS rules) ─────────────────────────────────────────
-
-;; JS `+`: if either operand is a string → string concat, else numeric.
 (define
   js-invoke-method
   (fn
@@ -398,11 +411,11 @@
       ((= code 122) "z")
       (else ""))))
 
+;; Bitwise + logical-not
 (define
   js-invoke-method-dyn
   (fn (recv key args) (js-invoke-method recv key args)))
 
-;; Bitwise + logical-not
 (define
   js-call-plain
   (fn
@@ -414,6 +427,9 @@
         (js-call-with-this :js-undefined (get fn-val "__callable__") args))
       (else (js-call-with-this :js-undefined fn-val args)))))
 
+;; ── Equality ──────────────────────────────────────────────────────
+
+;; Strict equality (===): no coercion; js-undefined matches js-undefined.
 (define
   js-new-call
   (fn
@@ -429,9 +445,6 @@
             ret
             obj))))))
 
-;; ── Equality ──────────────────────────────────────────────────────
-
-;; Strict equality (===): no coercion; js-undefined matches js-undefined.
 (define
   js-instanceof
   (fn
@@ -445,6 +458,9 @@
           ((proto (js-get-ctor-proto ctor)))
           (js-instanceof-walk obj proto))))))
 
+;; Abstract equality (==): type coercion rules.
+;; Simplified: number↔string coerce both to number; null == undefined;
+;; everything else falls back to strict equality.
 (define
   js-instanceof-walk
   (fn
@@ -460,9 +476,6 @@
             ((not (= (type-of p) "dict")) false)
             (else (js-instanceof-walk p proto))))))))
 
-;; Abstract equality (==): type coercion rules.
-;; Simplified: number↔string coerce both to number; null == undefined;
-;; everything else falls back to strict equality.
 (define
   js-in
   (fn
@@ -471,6 +484,11 @@
       ((not (= (type-of obj) "dict")) false)
       (else (js-in-walk obj (js-to-string key))))))
 
+;; ── Relational comparisons ────────────────────────────────────────
+
+;; Abstract relational comparison from ES5.
+;; Numbers compare numerically; two strings compare lexicographically;
+;; mixed types coerce both to numbers.
 (define
   js-in-walk
   (fn
@@ -481,11 +499,6 @@
       ((dict-has? obj "__proto__") (js-in-walk (get obj "__proto__") skey))
       (else false))))
 
-;; ── Relational comparisons ────────────────────────────────────────
-
-;; Abstract relational comparison from ES5.
-;; Numbers compare numerically; two strings compare lexicographically;
-;; mixed types coerce both to numbers.
 (define
   Error
   (fn
@@ -588,8 +601,6 @@
         (= t "component")
         (and (= t "dict") (contains? (keys v) "__callable__"))))))
 
-(define __js_proto_table__ (dict))
-
 ;; ── Property access ───────────────────────────────────────────────
 
 ;; obj[key] or obj.key in JS. Handles:
@@ -597,10 +608,13 @@
 ;;   • lists indexed by number (incl. .length)
 ;;   • strings indexed by number (incl. .length)
 ;; Returns js-undefined if the key is absent.
+(define __js_proto_table__ (dict))
+
 (define __js_next_id__ (dict))
 
 (dict-set! __js_next_id__ "n" 0)
 
+;; Setter — mutates the dict. Returns the new value (JS assignment yields rhs).
 (define
   js-get-ctor-proto
   (fn
@@ -612,7 +626,10 @@
         (else
           (let ((p (dict))) (begin (dict-set! __js_proto_table__ id p) p)))))))
 
-;; Setter — mutates the dict. Returns the new value (JS assignment yields rhs).
+;; ── Short-circuit logical ops ─────────────────────────────────────
+
+;; `a && b` in JS: if a is truthy return b else return a. The thunk
+;; form defers evaluation of b — the transpiler passes (fn () b).
 (define
   js-reset-ctor-proto!
   (fn
@@ -621,16 +638,15 @@
       ((id (js-ctor-id ctor)) (p (dict)))
       (begin (dict-set! __js_proto_table__ id p) p))))
 
-;; ── Short-circuit logical ops ─────────────────────────────────────
-
-;; `a && b` in JS: if a is truthy return b else return a. The thunk
-;; form defers evaluation of b — the transpiler passes (fn () b).
 (define
   js-set-ctor-proto!
   (fn
     (ctor proto)
     (let ((id (js-ctor-id ctor))) (dict-set! __js_proto_table__ id proto))))
 
+;; ── console.log ───────────────────────────────────────────────────
+
+;; Trivial bridge. `log-info` is available on OCaml; fall back to print.
 (define
   js-ctor-id
   (fn
@@ -640,9 +656,6 @@
         (get ctor "__ctor_id__"))
       (else (inspect ctor)))))
 
-;; ── console.log ───────────────────────────────────────────────────
-
-;; Trivial bridge. `log-info` is available on OCaml; fall back to print.
 (define
   js-typeof
   (fn
@@ -660,6 +673,8 @@
         "function")
       (else "object"))))
 
+;; ── Math object ───────────────────────────────────────────────────
+
 (define
   js-to-boolean
   (fn
@@ -671,9 +686,6 @@
       ((= v 0) false)
       ((= v "") false)
       (else true))))
-
-;; ── Math object ───────────────────────────────────────────────────
-
 (define
   js-to-number
   (fn
@@ -743,7 +755,8 @@
 (define js-trim (fn (s) (js-trim-left (js-trim-right s))))
 (define
   js-trim-left
-  (fn (s) (let ((n (len s))) (js-trim-left-at s n 0))))
+  (fn (s) (let ((n (len s))) (js-trim-left-at s n 0))))   ; deterministic placeholder for tests
+
 (define
   js-trim-left-at
   (fn
@@ -751,16 +764,16 @@
     (cond
       ((>= i n) "")
       ((js-is-space? (char-at s i)) (js-trim-left-at s n (+ i 1)))
-      (else (substr s i n)))))   ; deterministic placeholder for tests
-
-(define
-  js-trim-right
-  (fn (s) (let ((n (len s))) (js-trim-right-at s n))))
+      (else (substr s i n)))))
 
 ;; The global object — lookup table for JS names that aren't in the
 ;; SX env. Transpiled idents look up locally first; globals here are a
 ;; fallback, but most slice programs reference `console`, `Math`,
 ;; `undefined` as plain symbols, which we bind as defines above.
+(define
+  js-trim-right
+  (fn (s) (let ((n (len s))) (js-trim-right-at s n))))
+
 (define
   js-trim-right-at
   (fn
@@ -1941,8 +1954,12 @@
           (js-dict-get-walk obj (js-to-string key)))
         ((and (= obj Promise) (dict-has? __js_promise_statics__ (js-to-string key)))
           (get __js_promise_statics__ (js-to-string key)))
-        ((and (js-function? obj) (= (js-to-string key) "prototype"))
-          (js-get-ctor-proto obj))
+        ((and (js-function? obj) (or (= key "prototype") (= key "name") (= key "length") (= key "call") (= key "apply") (= key "bind")))
+          (cond
+            ((= key "prototype") (js-get-ctor-proto obj))
+            ((= key "name") "")
+            ((= key "length") 0)
+            (else (js-invoke-function-bound obj key))))
         (else js-undefined))))
   (define
     js-dict-get-walk