js-on-sx: Function.prototype.call/apply/bind

Adds js-invoke-function-method dispatched from js-invoke-method when the receiver is a JS function (lambda/function/component/callable-dict) and the method name is one of call/apply/bind/toString/name/length. call and apply bind this around a single call; bind returns a closure with prepended args. toString returns the native-code placeholder. 6 unit tests, 450/452 total (Array.prototype.push.call with arrayLike still fails — tracked as the 455x 'Not callable array-like' scoreboard item which needs array methods to treat dict-with-length as a list). Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-04-24 06:27:18 +00:00
parent 1774a900aa
commit 92c1fc72a5
2 changed files with 120 additions and 47 deletions
--- a/lib/js/runtime.sx
+++ b/lib/js/runtime.sx
@@ -54,6 +54,57 @@
 ;; Safe number-parser. Tries to call an SX primitive that can parse
 ;; strings to numbers; on failure returns 0 (stand-in for NaN so the
 ;; slice doesn't crash).
+(define
+  js-function-method?
+  (fn
+    (name)
+    (or
+      (= name "call")
+      (= name "apply")
+      (= name "bind")
+      (= name "toString")
+      (= name "name")
+      (= name "length"))))
+
+;; Minimal string->number for the slice. Handles integers, negatives,
+;; and simple decimals. Returns 0 on malformed input.
+(define
+  js-invoke-function-method
+  (fn
+    (recv key args)
+    (cond
+      ((= key "call")
+        (let
+          ((this-arg (if (< (len args) 1) :js-undefined (nth args 0)))
+            (rest
+              (if
+                (< (len args) 1)
+                (list)
+                (js-list-slice args 1 (len args)))))
+          (js-call-with-this this-arg recv rest)))
+      ((= key "apply")
+        (let
+          ((this-arg (if (< (len args) 1) :js-undefined (nth args 0)))
+            (arr (if (< (len args) 2) (list) (nth args 1))))
+          (let
+            ((rest (cond ((= arr nil) (list)) ((js-undefined? arr) (list)) ((list? arr) arr) (else (js-iterable-to-list arr)))))
+            (js-call-with-this this-arg recv rest))))
+      ((= key "bind")
+        (let
+          ((this-arg (if (< (len args) 1) :js-undefined (nth args 0)))
+            (bound
+              (if
+                (< (len args) 1)
+                (list)
+                (js-list-slice args 1 (len args)))))
+          (fn
+            (&rest more)
+            (js-call-with-this this-arg recv (js-list-concat bound more)))))
+      ((= key "toString") "function () { [native code] }")
+      ((= key "name") "")
+      ((= key "length") 0)
+      (else :js-undefined))))
+
 (define
  js-apply-fn
  (fn
@@ -85,8 +136,6 @@
            (nth args 5)))
        (else (apply callable args))))))

-;; Minimal string->number for the slice. Handles integers, negatives,
-;; and simple decimals. Returns 0 on malformed input.
 (define
  js-invoke-method
  (fn
@@ -100,7 +149,9 @@
          ((m (js-get-prop recv key)))
          (cond
            ((not (js-undefined? m)) (js-call-with-this recv m args))
-            ((and (dict? recv) (js-object-builtin-method? key))
+            ((and (js-function? recv) (js-function-method? key))
+              (js-invoke-function-method recv key args))
+            ((and (= (type-of recv) "dict") (js-object-builtin-method? key))
              (js-invoke-object-method recv key args))
            (else
              (error
@@ -143,6 +194,13 @@

 (define js-lower-case (fn (s) (js-case-loop s 0 "" false)))

+;; 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-case-loop
  (fn
@@ -217,17 +275,12 @@
      ((= code 122) "z")
      (else ""))))

-;; 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-invoke-method-dyn
  (fn (recv key args) (js-invoke-method recv key args)))

+;; ── String coercion (ToString) ────────────────────────────────────
+
 (define
  js-call-plain
  (fn
@@ -254,8 +307,9 @@
            ret
            obj))))))

-;; ── String coercion (ToString) ────────────────────────────────────
+;; ── Arithmetic (JS rules) ─────────────────────────────────────────

+;; JS `+`: if either operand is a string → string concat, else numeric.
 (define
  js-instanceof
  (fn
@@ -284,9 +338,6 @@
            ((not (= (type-of p) "dict")) false)
            (else (js-instanceof-walk p proto))))))))

-;; ── Arithmetic (JS rules) ─────────────────────────────────────────
-
-;; JS `+`: if either operand is a string → string concat, else numeric.
 (define
  js-in
  (fn
@@ -377,6 +428,7 @@
          nil)
        this))))

+;; Bitwise + logical-not
 (define
  ReferenceError
  (fn
@@ -407,14 +459,16 @@
        (= t "component")
        (and (= t "dict") (contains? (keys v) "__callable__"))))))

-;; Bitwise + logical-not
+;; ── Equality ──────────────────────────────────────────────────────
+
+;; Strict equality (===): no coercion; js-undefined matches js-undefined.
 (define __js_proto_table__ (dict))

 (define __js_next_id__ (dict))

-;; ── Equality ──────────────────────────────────────────────────────
-
-;; Strict equality (===): no coercion; js-undefined matches js-undefined.
+;; Abstract equality (==): type coercion rules.
+;; Simplified: number↔string coerce both to number; null == undefined;
+;; everything else falls back to strict equality.
 (dict-set! __js_next_id__ "n" 0)

 (define
@@ -428,9 +482,11 @@
        (else
          (let ((p (dict))) (begin (dict-set! __js_proto_table__ id p) p)))))))

-;; Abstract equality (==): type coercion rules.
-;; Simplified: number↔string coerce both to number; null == undefined;
-;; everything else falls back to strict equality.
+;; ── Relational comparisons ────────────────────────────────────────
+
+;; Abstract relational comparison from ES5.
+;; Numbers compare numerically; two strings compare lexicographically;
+;; mixed types coerce both to numbers.
 (define
  js-reset-ctor-proto!
  (fn
@@ -445,11 +501,6 @@
    (ctor proto)
    (let ((id (js-ctor-id ctor))) (dict-set! __js_proto_table__ id proto))))

-;; ── Relational comparisons ────────────────────────────────────────
-
-;; Abstract relational comparison from ES5.
-;; Numbers compare numerically; two strings compare lexicographically;
-;; mixed types coerce both to numbers.
 (define
  js-ctor-id
  (fn
@@ -505,6 +556,13 @@
  js-string-to-number
  (fn (s) (cond ((= s "") 0) (else (js-parse-num-safe s)))))

+;; ── Property access ───────────────────────────────────────────────
+
+;; obj[key] or obj.key in JS. Handles:
+;;   • dicts keyed by string
+;;   • lists indexed by number (incl. .length)
+;;   • strings indexed by number (incl. .length)
+;; Returns js-undefined if the key is absent.
 (define js-parse-num-safe (fn (s) (cond (else (js-num-from-string s)))))

 (define
@@ -517,19 +575,17 @@
        ((= trimmed "") 0)
        (else (js-parse-decimal trimmed 0 0 1 false 0))))))

-;; ── Property access ───────────────────────────────────────────────
-
-;; obj[key] or obj.key in JS. Handles:
-;;   • dicts keyed by string
-;;   • lists indexed by number (incl. .length)
-;;   • strings indexed by number (incl. .length)
-;; Returns js-undefined if the key is absent.
 (define js-trim (fn (s) (js-trim-left (js-trim-right s))))

+;; Setter — mutates the dict. Returns the new value (JS assignment yields rhs).
 (define
  js-trim-left
  (fn (s) (let ((n (len s))) (js-trim-left-at s n 0))))

+;; ── 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-trim-left-at
  (fn
@@ -539,15 +595,13 @@
      ((js-is-space? (char-at s i)) (js-trim-left-at s n (+ i 1)))
      (else (substr s i n)))))

-;; Setter — mutates the dict. Returns the new value (JS assignment yields rhs).
 (define
  js-trim-right
  (fn (s) (let ((n (len s))) (js-trim-right-at s n))))

-;; ── Short-circuit logical ops ─────────────────────────────────────
+;; ── console.log ───────────────────────────────────────────────────

-;; `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).
+;; Trivial bridge. `log-info` is available on OCaml; fall back to print.
 (define
  js-trim-right-at
  (fn
@@ -561,9 +615,8 @@
  js-is-space?
  (fn (c) (or (= c " ") (= c "\t") (= c "\n") (= c "\r"))))

-;; ── console.log ───────────────────────────────────────────────────
+;; ── Math object ───────────────────────────────────────────────────

-;; Trivial bridge. `log-info` is available on OCaml; fall back to print.
 (define
  js-parse-decimal
  (fn
@@ -596,7 +649,6 @@
              false
              0)))
        (else (* sign (if frac? (/ acc fdiv) acc)))))))
-
 (define
  js-is-digit?
  (fn
@@ -613,9 +665,6 @@
        (= c "7")
        (= c "8")
        (= c "9")))))
-
-;; ── Math object ───────────────────────────────────────────────────
-
 (define
  js-digit-val
  (fn
@@ -667,16 +716,18 @@
      ((or (= (type-of a) "string") (= (type-of b) "string"))
        (str (js-to-string a) (js-to-string b)))
      (else (+ (js-to-number a) (js-to-number b))))))
-(define js-sub (fn (a b) (- (js-to-number a) (js-to-number b))))
-(define js-mul (fn (a b) (* (js-to-number a) (js-to-number b))))
-(define js-div (fn (a b) (/ (js-to-number a) (js-to-number b))))   ; deterministic placeholder for tests
+(define js-sub (fn (a b) (- (js-to-number a) (js-to-number b))))   ; deterministic placeholder for tests

-(define js-mod (fn (a b) (mod (js-to-number a) (js-to-number b))))
+(define js-mul (fn (a b) (* (js-to-number a) (js-to-number b))))

 ;; 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-div (fn (a b) (/ (js-to-number a) (js-to-number b))))
+
+(define js-mod (fn (a b) (mod (js-to-number a) (js-to-number b))))
+
 (define js-pow (fn (a b) (pow (js-to-number a) (js-to-number b))))

 (define js-neg (fn (a) (- 0 (js-to-number a))))
--- a/lib/js/test.sh
+++ b/lib/js/test.sh
@@ -1147,6 +1147,20 @@ cat > "$TMPFILE" << 'EPOCHS'
 (epoch 3301)
 (eval "(js-eval \"var o = {a:1, b:2}; delete o.a; o.b\")")

+;; ── Phase 11.fnmethod: Function.prototype.call/apply/bind ─────
+(epoch 3400)
+(eval "(js-eval \"function greet3(n) { return 'hi ' + n; } greet3.call(null, 'ada')\")")
+(epoch 3401)
+(eval "(js-eval \"function greet4(n) { return 'hi ' + n; } greet4.apply(null, ['bob'])\")")
+(epoch 3402)
+(eval "(js-eval \"function sum3(a,b,c) { return a+b+c; } var bnd2 = sum3.bind(null, 1, 2); bnd2(3)\")")
+(epoch 3403)
+(eval "(js-eval \"var obj2 = {x: 42}; function getX() { return this.x; } getX.call(obj2)\")")
+(epoch 3404)
+(eval "(js-eval \"function id(x) { return x; } id.apply(null, [7])\")")
+(epoch 3405)
+(eval "(js-eval \"var arr2 = [1,2]; Array.prototype.push.call(arr2, 10, 20); arr2.length\")")
+
 EPOCHS


@@ -1770,6 +1784,14 @@ check 3201 "obj multi rename"              '3'
 check 3300 "delete obj.x"                  'true'
 check 3301 "delete obj.a keeps b"         '2'

+# ── Phase 11.fnmethod: call/apply/bind ────────────────────────
+check 3400 "fn.call basic"                 '"hi ada"'
+check 3401 "fn.apply basic"                '"hi bob"'
+check 3402 "fn.bind partial"               '6'
+check 3403 "fn.call this-binding"          '42'
+check 3404 "fn.apply arg-unpack"           '7'
+check 3405 "Array.prototype.push.call arr" '4'
+
 TOTAL=$((PASS + FAIL))
 if [ $FAIL -eq 0 ]; then
  echo "✓ $PASS/$TOTAL JS-on-SX tests passed"