From 802544fdc652a04934fb7e3e5773c05488102f6c Mon Sep 17 00:00:00 2001
From: giles <giles.bradshaw@rose-ash.com>
Date: Sat, 9 May 2026 14:13:57 +0000
Subject: [PATCH] js-on-sx: call/apply box primitive thisArg per non-strict
 ToObject

---
 lib/js/runtime.sx | 24 ++++++++++++++++--------
 plans/js-on-sx.md |  2 ++
 2 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/lib/js/runtime.sx b/lib/js/runtime.sx
index c2c74a6b..6301e476 100644
--- a/lib/js/runtime.sx
+++ b/lib/js/runtime.sx
@@ -326,6 +326,19 @@
             0
             (+ 1 (js-count-real-params (rest params)))))))))
 
+(define
+  js-coerce-this-arg
+  (fn
+    (v)
+    (cond
+      ((js-undefined? v) js-global-this)
+      ((= v nil) js-global-this)
+      ((or (= (type-of v) "number") (= (type-of v) "rational"))
+        (js-new-call Number (js-args v)))
+      ((= (type-of v) "string") (js-new-call String (js-args v)))
+      ((= (type-of v) "boolean") (js-new-call Boolean (js-args v)))
+      (else v))))
+
 (define
   js-invoke-function-method
   (fn
@@ -339,20 +352,15 @@
                 (< (len args) 1)
                 (list)
                 (js-list-slice args 1 (len args)))))
-          (let
-            ((this-arg
-               (if (or (js-undefined? raw-this) (= raw-this nil)) js-global-this raw-this)))
-            (js-call-with-this this-arg recv rest))))
+          (js-call-with-this (js-coerce-this-arg raw-this) recv rest)))
       ((= key "apply")
         (let
           ((raw-this (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))))
-              (this-arg
-                (if (or (js-undefined? raw-this) (= raw-this nil)) js-global-this raw-this)))
-            (js-call-with-this this-arg recv rest))))
+            ((rest (cond ((= arr nil) (list)) ((js-undefined? arr) (list)) ((list? arr) arr) (else (js-iterable-to-list arr)))))
+            (js-call-with-this (js-coerce-this-arg raw-this) recv rest))))
       ((= key "bind")
         (cond
           ((not (js-function? recv))
diff --git a/plans/js-on-sx.md b/plans/js-on-sx.md
index 3253d9c1..c1edaf5b 100644
--- a/plans/js-on-sx.md
+++ b/plans/js-on-sx.md
@@ -158,6 +158,8 @@ Each item: implement → tests → update progress. Mark `[x]` when tests green.
 
 Append-only record of completed iterations. Loop writes one line per iteration: date, what was done, test count delta.
 
+- 2026-05-09 — **`Function.prototype.call` / `apply` box primitive `thisArg` per non-strict ToObject.** Per spec, in non-strict mode the called function receives `ToObject(thisArg)` as `this` — so `f.call(1)` should see a `Number(1)` wrapper, not the raw primitive. We were passing primitives through unchanged, so `this.touched = true` inside the function silently no-op'd (`js-set-prop` on a number returns val unchanged). Extracted a `js-coerce-this-arg` helper that does the spec coercion: undefined/null → globalThis, number/rational → `new Number(v)`, string → `new String(v)`, boolean → `new Boolean(v)`, else as-is. Result: built-ins/Function/prototype/call 19/30 → 23/30, apply 22/30 → 25/30. bind 22/30, Object 30/30 unchanged. conformance.sh: 148/148.
+
 - 2026-05-09 — **`Function.prototype.bind` throws TypeError when target isn't callable.** Per spec step 2 of `bind`, if the target (the receiver) isn't callable, throw TypeError. We were happily building a `(fn (&rest more) ...)` closure that would later fail to call — long after the bind() invocation. Added a `(not (js-function? recv))` guard at the top of the bind branch in `js-invoke-function-method` that raises a `TypeError` instance via `js-new-call`. Now `Function.prototype.bind.call(undefined)` etc. throw at the bind call site. Result: built-ins/Function/prototype/bind 14/30 → 22/30 (+8), call 18/30 → 19/30. Object 30/30. conformance.sh: 148/148.
 
 - 2026-05-09 — **`Function.prototype.{call, apply, bind}` carry their spec lengths and names.** Per spec, `Function.prototype.call.length === 1`, `apply.length === 2`, `bind.length === 1`. We were storing them as bare lambdas with `&rest args`, so `js-fn-length` fell back to the param-counting path which yielded 0. Wrapped each in the dict-with-`__callable__` pattern with explicit `length` and `name` slots; `toString` got `length: 0`. Result: built-ins/Function/prototype/apply 18/30 → 22/30, call 17/30 → 18/30. bind 14/30 holds (its remaining failures are deeper bind semantics — bound length, target check). Object 30/30. conformance.sh: 148/148.