js-on-sx: array elision, list-instanceof-Array, array toString identity

lib/js/parser.sx

@@ -537,6 +537,11 @@
     (st elems)
     (cond
       ((jp-at? st "punct" "]") nil)
+      ((jp-at? st "punct" ",")
+        (begin
+          (append! elems (list (quote js-undef)))
+          (jp-advance! st)
+          (jp-array-loop st elems)))
       (else
         (begin
           (cond

lib/js/runtime.sx

@@ -809,6 +809,15 @@
             ((and (= (type-of obj) "dict") (contains? (keys obj) "__proto__"))
               (js-instanceof-walk obj proto))
             (else false))))
+      ((list? obj)
+        (let
+          ((proto (js-get-ctor-proto ctor))
+            (arrproto (get Array "prototype"))
+            (objproto (get Object "prototype")))
+          (cond
+            ((= proto arrproto) true)
+            ((= proto objproto) true)
+            (else false))))
       ((not (= (type-of obj) "dict")) false)
       (else
         (let
@@ -3327,7 +3336,7 @@
             ((= key "findLast") (js-array-method obj "findLast"))
             ((= key "findLastIndex") (js-array-method obj "findLastIndex"))
             ((= key "reduceRight") (js-array-method obj "reduceRight"))
-            ((= key "toString") (js-array-method obj "toString"))
+            ((= key "toString") (js-dict-get-walk (get Array "prototype") "toString"))
             ((= key "toLocaleString") (js-array-method obj "toLocaleString"))
             ((= key "keys") (js-array-method obj "keys"))
             ((= key "values") (js-array-method obj "values"))