On Apr 2, 2012, at 2:12 PM, Brendan Eich wrote:
> Jorge wrote:
>>
>> No [[Scope]]? I must be missing something! Given this code:
>>
>> bound= (function a(i) { return function b () { return i }.bind(null) })(27);
>> bound()
>> --> 27
>>
>> How can bound() resolve `i` without a [[Scope]] ?
>
> By delegating to bound()'s [[TargetFunction]], which does have a [[Scope]] --
> see ES5 15.3.4.5.1 and 15.3.4.5.2.
Oh, I see. Thank you!
>>> > 6. Arrow functions (AF). Features: captured `this', captured `this' even
>>> > in case of `new'.
>>
>> And [[Extensible]] === false... I wonder why, why non-extensible ?
>
> No, arrows are extensible -- where did you see [[Extensible]] === false?
I saw it here:
<http://www.yuiblog.com/blog/2012/03/30/what-is-the-meaning-of-this>
"Function objects are mutable like other objects. This will make the securing
of JavaScript more difficult because every function object can be used as a
channel to facilitate unwanted collusion between widgets. ES5 provides tools to
freeze functions, making them immutable, but the tools are really difficult to
use for that purpose. The Sixth Edition of ECMAScript may correct all of these
problems."
...
"Fat arrow functions do not have prototype properties, which makes them cheaper
to make. They are immutable."
...
"You will need the old functions to make mutable functions, although I don’t
recommend those either."
--
Jorge.
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