Add support for defineProperties

Issue angelozerr#377

Author: marijnh

defs/ecma5.json

@@ -34,7 +34,7 @@
       "!doc": "Defines a new property directly on an object, or modifies an existing property on an object, and returns the object. If you want to see how to use the Object.defineProperty method with a binary-flags-like syntax, see this article."
     },
     "defineProperties": {
-      "!type": "fn(obj: ?, props: ?)",
+      "!type": "fn(obj: ?, props: ?) -> !custom:Object_defineProperties",
       "!url": "https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Object/defineProperty",
       "!doc": "Defines a new property directly on an object, or modifies an existing property on an object, and returns the object. If you want to see how to use the Object.defineProperty method with a binary-flags-like syntax, see this article."
     },

lib/def.js

@@ -533,6 +533,19 @@
     return infer.ANull;
   });
 
+  infer.registerFunction("Object_defineProperties", function(_self, args, argNodes) {
+    if (args.length >= 2) {
+      var obj = args[0];
+      args[1].forAllProps(function(prop, val, local) {
+        if (!local) return;
+        var connect = new infer.AVal;
+        obj.propagate(new infer.PropHasSubset(prop, connect, argNodes && argNodes[1]));
+        val.propagate(new PropSpec(connect));
+      });
+    }
+    return infer.ANull;
+  });
+
   var IsBound = infer.constraint("self, args, target", {
     addType: function(tp) {
       if (!(tp instanceof infer.Fn)) return;

test/cases/defineProperty.js

@@ -13,3 +13,13 @@ o.prop1; //: string
 o.prop2; //: number
 
 o.prop1; //doc: Docstring for prop1
+
+var o2 = {};
+
+Object.defineProperties(o2, {
+  prop1: {get: function() { return 2; }},
+  prop2: {value: true}
+});
+
+o2.prop1; //: number
+o2.prop2; //: bool