js-on-sx: wrapper constructor-detection, Array.prototype.toString, >>> operator

Number.__callable__ and String.__callable__ now check this.__proto__ ===
Number/String.prototype before writing wrapper slots, preventing false-positive
mutation when called as plain function. js-to-number extended to unwrap
wrapper dicts and call valueOf/toString for plain objects. Array.prototype.toString
replaced with a direct js-list-join implementation (eliminates infinite recursion
via js-invoke-method on dict-based arrays). >>> added to transpiler + runtime.

String test262 subset: 62→66/100. 529/530 unit, 147/148 slice.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/js/runtime.sx

@@ -904,6 +904,36 @@
       ((= v false) 0)
       ((= (type-of v) "number") v)
       ((= (type-of v) "string") (js-string-to-number v))
+      ((= (type-of v) "dict")
+        (cond
+          ((contains? (keys v) "__js_number_value__")
+            (get v "__js_number_value__"))
+          ((contains? (keys v) "__js_boolean_value__")
+            (if (get v "__js_boolean_value__") 1 0))
+          ((contains? (keys v) "__js_string_value__")
+            (js-string-to-number (get v "__js_string_value__")))
+          (else
+            (let
+              ((valueof-fn (js-get-prop v "valueOf")))
+              (if
+                (= (type-of valueof-fn) "lambda")
+                (let
+                  ((result (js-call-with-this v valueof-fn ())))
+                  (if
+                    (not (= (type-of result) "dict"))
+                    (js-to-number result)
+                    (let
+                      ((tostr-fn (js-get-prop v "toString")))
+                      (if
+                        (= (type-of tostr-fn) "lambda")
+                        (let
+                          ((result2 (js-call-with-this v tostr-fn ())))
+                          (if
+                            (not (= (type-of result2) "dict"))
+                            (js-to-number result2)
+                            (js-nan-value)))
+                        (js-nan-value)))))
+                (js-nan-value))))))
       (else 0))))
 
 (define
@@ -1172,10 +1202,35 @@
       (else
         (if
           (= (type-of v) "dict")
-          (if
-            (contains? (keys v) "__js_string_value__")
-            (get v "__js_string_value__")
-            "[object Object]")
+          (cond
+            ((contains? (keys v) "__js_string_value__")
+              (get v "__js_string_value__"))
+            ((contains? (keys v) "__js_number_value__")
+              (js-number-to-string (get v "__js_number_value__")))
+            ((contains? (keys v) "__js_boolean_value__")
+              (if (get v "__js_boolean_value__") "true" "false"))
+            (else
+              (let
+                ((tostr-fn (js-get-prop v "toString")))
+                (if
+                  (= (type-of tostr-fn) "lambda")
+                  (let
+                    ((result (js-call-with-this v tostr-fn ())))
+                    (if
+                      (= (type-of result) "dict")
+                      (let
+                        ((valueof-fn (js-get-prop v "valueOf")))
+                        (if
+                          (= (type-of valueof-fn) "lambda")
+                          (let
+                            ((result2 (js-call-with-this v valueof-fn ())))
+                            (if
+                              (= (type-of result2) "dict")
+                              "[object Object]"
+                              (js-to-string result2)))
+                          "[object Object]"))
+                      (js-to-string result)))
+                  "[object Object]"))))
           (str v))))))
 
 (define
@@ -1348,6 +1403,15 @@
 
 (define js-mod (fn (a b) (mod (js-to-number a) (js-to-number b))))
 
+(define
+  js-unsigned-rshift
+  (fn
+    (l r)
+    (let
+      ((lu32 (modulo (js-math-trunc (js-to-number l)) 4294967296))
+        (shift (modulo (js-math-trunc (js-to-number r)) 32)))
+      (floor (/ lu32 (js-math-pow 2 shift))))))
+
 (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))))
@@ -1990,11 +2054,11 @@
         (fn
           (i)
           (let
-            ((idx (js-num-to-int i)))
+            ((idx (js-num-to-int (js-to-number i))))
             (if
-              (and (>= idx 0) (< idx (len s)))
-              (char-code (char-at s idx))
-              0))))
+              (and (>= idx 0) (< idx (unicode-len s)))
+              (unicode-char-code-at s idx)
+              (js-nan-value)))))
       ((= name "indexOf")
         (fn
           (&rest args)
@@ -2402,7 +2466,7 @@
             (else js-undefined)))
         ((= (type-of obj) "string")
           (cond
-            ((= key "length") (len obj))
+            ((= key "length") (unicode-len obj))
             ((= (type-of key) "number")
               (if
                 (and (>= key 0) (< key (len obj)))
@@ -2709,6 +2773,52 @@
 
 (dict-set! (get Number "prototype") "constructor" Number)
 
+(dict-set!
+  Number
+  "__callable__"
+  (fn
+    (&rest args)
+    (let
+      ((raw (if (= (len args) 0) 0 (js-to-number (nth args 0)))))
+      (let
+        ((this-val (js-this)))
+        (if
+          (and
+            (dict? this-val)
+            (contains? (keys this-val) "__proto__")
+            (= (get this-val "__proto__") (get Number "prototype")))
+          (begin (dict-set! this-val "__js_number_value__" raw) this-val)
+          raw)))))
+
+(dict-set!
+  (get Number "prototype")
+  "valueOf"
+  (fn
+    ()
+    (let
+      ((this-val (js-this)))
+      (if
+        (and
+          (dict? this-val)
+          (contains? (keys this-val) "__js_number_value__"))
+        (get this-val "__js_number_value__")
+        this-val))))
+
+(dict-set!
+  (get Number "prototype")
+  "toString"
+  (fn
+    (&rest args)
+    (let
+      ((this-raw (js-this)))
+      (let
+        ((this-val (if (and (dict? this-raw) (contains? (keys this-raw) "__js_number_value__")) (get this-raw "__js_number_value__") this-raw)))
+        (let
+          ((radix (if (empty? args) 10 (js-to-number (nth args 0)))))
+          (js-num-to-str-radix
+            this-val
+            (if (or (= radix nil) (js-undefined? radix)) 10 radix)))))))
+
 (define isFinite js-global-is-finite)
 
 (define isNaN js-global-is-nan)
@@ -3167,6 +3277,17 @@
 
 (dict-set! Array "name" "Array")
 
+(dict-set!
+  (get Array "prototype")
+  "toString"
+  (fn
+    (&rest args)
+    (let
+      ((this-val (js-this)))
+      (let
+        ((items (cond ((list? this-val) this-val) ((and (dict? this-val) (contains? (keys this-val) "length")) (js-arraylike-to-list this-val)) (else (list)))))
+        (js-list-join items ",")))))
+
 (define
   js-string-from-char-code
   (fn (&rest args) (js-string-from-char-code-loop args 0 "")))
@@ -3207,10 +3328,14 @@
     (if
       (>= i (len args))
       acc
-      (js-string-from-char-code-loop
-        args
-        (+ i 1)
-        (str acc (js-code-to-char (js-num-to-int (nth args i))))))))
+      (let
+        ((n (js-to-number (nth args i))))
+        (let
+          ((code (if (js-global-is-nan n) 0 (modulo (js-math-trunc n) 65536))))
+          (js-string-from-char-code-loop
+            args
+            (+ i 1)
+            (str acc (char-from-code code))))))))
 
 (define
   js-string-proto-fn
@@ -3220,7 +3345,9 @@
       (&rest args)
       (let
         ((this-val (js-this)))
-        (js-invoke-method (js-to-string this-val) name args)))))
+        (let
+          ((s (cond ((= (type-of this-val) "string") this-val) ((and (= (type-of this-val) "dict") (contains? (keys this-val) "__js_string_value__")) (get this-val "__js_string_value__")) (else "[object Object]"))))
+          (js-invoke-method s name args))))))
 
 (define String {:fromCharCode js-string-from-char-code :__callable__ (fn (&rest args) (if (= (len args) 0) "" (js-to-string (nth args 0)))) :prototype {:toLowerCase (js-string-proto-fn "toLowerCase") :concat (js-string-proto-fn "concat") :startsWith (js-string-proto-fn "startsWith") :padEnd (js-string-proto-fn "padEnd") :codePointAt (js-string-proto-fn "codePointAt") :lastIndexOf (js-string-proto-fn "lastIndexOf") :indexOf (js-string-proto-fn "indexOf") :localeCompare (js-string-proto-fn "localeCompare") :split (js-string-proto-fn "split") :endsWith (js-string-proto-fn "endsWith") :trim (js-string-proto-fn "trim") :valueOf (js-string-proto-fn "valueOf") :at (js-string-proto-fn "at") :normalize (js-string-proto-fn "normalize") :substring (js-string-proto-fn "substring") :replaceAll (js-string-proto-fn "replaceAll") :repeat (js-string-proto-fn "repeat") :padStart (js-string-proto-fn "padStart") :search (js-string-proto-fn "search") :toUpperCase (js-string-proto-fn "toUpperCase") :trimEnd (js-string-proto-fn "trimEnd") :toString (js-string-proto-fn "toString") :toLocaleLowerCase (js-string-proto-fn "toLocaleLowerCase") :charCodeAt (js-string-proto-fn "charCodeAt") :slice (js-string-proto-fn "slice") :charAt (js-string-proto-fn "charAt") :match (js-string-proto-fn "match") :includes (js-string-proto-fn "includes") :trimStart (js-string-proto-fn "trimStart") :toLocaleUpperCase (js-string-proto-fn "toLocaleUpperCase") :replace (js-string-proto-fn "replace")} :raw (fn (&rest args) (if (empty? args) "" (js-to-string (nth args 0))))})
 
@@ -3232,6 +3359,8 @@
 
 (dict-set! String "fromCodePoint" js-string-from-code-point)
 
+(dict-set! String "fromCharCode" js-string-from-char-code)
+
 (dict-set!
   String
   "__callable__"
@@ -3242,7 +3371,10 @@
       (let
         ((this-val (js-this)))
         (if
-          (dict? this-val)
+          (and
+            (dict? this-val)
+            (contains? (keys this-val) "__proto__")
+            (= (get this-val "__proto__") (get String "prototype")))
           (begin
             (dict-set! this-val "__js_string_value__" raw)
             (dict-set! this-val "length" (len raw))
@@ -3260,6 +3392,50 @@
 
 (dict-set! Boolean "name" "Boolean")
 
+(dict-set! Boolean "prototype" {:constructor Boolean})
+
+(dict-set!
+  Boolean
+  "__callable__"
+  (fn
+    (&rest args)
+    (let
+      ((val (if (> (len args) 0) (js-to-boolean (nth args 0)) false)))
+      (let
+        ((this-val (js-this)))
+        (if
+          (dict? this-val)
+          (begin
+            (dict-set! this-val "__js_boolean_value__" val)
+            (dict-set! this-val "__proto__" (get Boolean "prototype"))
+            this-val)
+          (if val true false))))))
+
+(dict-set!
+  (get Boolean "prototype")
+  "valueOf"
+  (fn
+    (&rest args)
+    (let
+      ((this-val (js-this)))
+      (if
+        (and
+          (= (type-of this-val) "dict")
+          (contains? (keys this-val) "__js_boolean_value__"))
+        (get this-val "__js_boolean_value__")
+        this-val))))
+
+(dict-set!
+  (get Boolean "prototype")
+  "toString"
+  (fn
+    (&rest args)
+    (let
+      ((this-val (js-this)))
+      (let
+        ((b (if (and (= (type-of this-val) "dict") (contains? (keys this-val) "__js_boolean_value__")) (get this-val "__js_boolean_value__") this-val)))
+        (if b "true" "false")))))
+
 (define
   parseInt
   (fn