(Resending on behalf of 张立理 <otakus...@live.com> because his mail didn't go through.)
According to [section 13 Function Definition](http://ecma-international.org/ecma-262/5.1/#sec-13) of ECMAScript-262 5.1, the **Function Declaration** production and the **Function Expression** production are nearly the same, except when they are in the process of [Create Function Objects](http://ecma-international.org/ecma-262/5.1/#sec-13.2), in which case they pass different **Scope** argument: Function Declaration passes the **VariableEnvironment** while Function Expression passes the **LexicalEnvironment**. This confuses me a little. Suppose we have this code: function test() { var x = 1; var o = { x: 2 }; with (o) { eval('function foo() { console.log(x); }'); eval('var bar = function() { console.log(x); }'); } foo(); bar(); } test(); If I understand correctly, here are 2 facts: - outside `with` statement, the **VariableEnvironment** and **LexicalEnvironment** refer to the same object, here we name it `outerEnv`. - inside `with` statement, we have a new **LexicalEnvironment** (object environment), the **VariableEnvironment** stays the same, here we name the new **LexicalEnvironment** `innerEnv`. The problem lies in the 2 direct `eval` calls. Without the **strict** flag, the `eval` function shares the same **LexicalEnvironment** and **VariableEnvironment** as its calling context. When the `eval` is invoked in a `with` statement, **VariableEnvironment** and **LexicalEnvironment** are different, so we expect `foo` and `bar` outputs different numbesr: `foo` should output `1` and `bar` should output `2`. The fact is, the edge version of Chrome, Firefox and IE7-10, all output `2` and `2`. Why is ECMAScript-262 5.1 documenting a behavior that's different from nearly all modern browsers? Should these browsers consider their implementations buggy, or should our standard change a little? Anyway, I could not image a situation when **Function Declaration** and **Function Expression** should use different objects as their `[[Scope]]` internal property, why not use **LexicalEnvironment** of its calling context as all browsers do? The `catch` statement has the same problem: function test() { var x = 1; try { throw 2; } catch (x) { eval('function foo() { console.log(x); }'); eval('var bar = function() { console.log(x); }'); } foo(); bar(); } test(); Thanks. Gray Zhang ------------- 电子邮件：otakus...@live.com 微博：@otakustay 博客：http://otakustay.com _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
