Simple implementation for working numeric array indexes.

ext/spidermonkey/js_land_proxy.c

@@ -73,6 +73,11 @@ static JSBool attribute_p(VALUE self, char* name)
         rb_intern("js_property?"), 2, self, ID2SYM(rb_id));
 }
 
+static JSBool indexable_p(VALUE self)
+{
+  rb_funcall(self, rb_intern("respond_to?"), 1, ID2SYM(rb_intern("[]")));
+}
+
 static JSBool has_key_p(VALUE self, char* name)
 {
   return rb_funcall(self, rb_intern("respond_to?"), 1, ID2SYM(rb_intern("[]")))
@@ -119,6 +124,17 @@ static JSBool get(JSContext* js_context, JSObject* obj, jsval id, jsval* retval)
   VALUE self;
   assert(self = (VALUE)JS_GetInstancePrivate(context->js, obj, JS_GET_CLASS(context->js, obj), NULL));
 
+  // Short-circuit for numeric indexes
+
+  if (JSVAL_IS_INT(id))
+  {
+    if (indexable_p(self))
+      *retval = convert_to_js(context,
+        rb_funcall(self, rb_intern("[]"), 1, INT2FIX(JSVAL_TO_INT(id))));
+
+    return JS_TRUE;
+  }
+
   char* name = JS_GetStringBytes(JSVAL_TO_STRING(id));
   VALUE ruby_id = rb_intern(name);
 
@@ -218,6 +234,17 @@ static JSBool set(JSContext* js_context, JSObject* obj, jsval id, jsval* value)
   VALUE self;
   assert(self = (VALUE)JS_GetInstancePrivate(context->js, obj, JS_GET_CLASS(context->js, obj), NULL));
 
+  // Short-circuit for numeric indexes
+
+  if (JSVAL_IS_INT(id))
+  {
+    if (indexable_p(self))
+      rb_funcall(self, rb_intern("[]="),
+        2, INT2FIX(JSVAL_TO_INT(id)), convert_to_ruby(context, *value));
+
+    return JS_TRUE;
+  }
+
   char* key = JS_GetStringBytes(JSVAL_TO_STRING(id));
   VALUE ruby_key = rb_str_new2(key);
 

test/johnson/conversions/array_test.rb

@@ -0,0 +1,36 @@
+require File.expand_path(File.join(File.dirname(__FILE__), "/../../helper"))
+
+module Johnson
+  module Conversions
+    class ArrayTest < Johnson::TestCase
+      def setup
+        @context = Johnson::Context.new
+      end
+
+      def test_array_index_get
+        @context[:list] = [1, 2, 3, 4]
+        assert_equal(1, @context.evaluate("list[0]"))
+      end
+
+      def test_array_index_set
+        @context[:list] = []
+        @context.evaluate("list[0] = 42")
+        assert_equal(42, @context[:list][0])
+      end
+
+      def test_array_works_with_for_in
+        list = [1, 2, 3, 4]
+
+        @context['alert'] = lambda { |x| p x }
+        @context['list'] = list
+        @context.evaluate("
+          var new_list = [];
+          for(x in list) {
+            new_list.push(x + 1);
+          }
+        ")
+        assert_equal(list.map { |x| x + 1}, @context['new_list'].to_a)
+      end
+    end
+  end
+end

test/johnson/spidermonkey/js_land_proxy_test.rb

@@ -79,20 +79,6 @@ def test_catch_missing_require
           }
         ")
       end
-
-      def test_array_gets_returned
-        list = [1,2,3,4]
-
-        @context['alert'] = lambda { |x| p x }
-        @context['list'] = list
-        @context.evaluate("
-          var new_list = [];
-          for(x in list) {
-            new_list.push(x + 1);
-          }
-        ")
-        assert_equal(list.map { |x| x + 1}, @context['new_list'].to_a)
-      end
 
       def test_proxies_get_reused
         @context["foo"] = @context["bar"] = Foo.new