arrow function syntax simplified

Dmitry Soshnikov dmitry.soshnikov at gmail.com
Sun Apr 1 01:13:41 PDT 2012


On Apr 1, 2012, at 12:34 AM, Axel Rauschmayer wrote:

>>> Ah, good. But one can use the above (pseudo-)desugaring to predict the behavior of arrow functions, right? That is, there is no observable difference.
>> 
>> There is, again, the difference in terms of delegation to the target's [[Construct]] in case of a bound function, see the spec ("bound" per ES5, of course, since, as Brendan notices, it's not just a syntactic sugar, but a new special type of functions).
> 
> OK. Ignoring [[Construct]] and .prototype, any other differences?

Well, "ES5-bounds" also do not have `prototype' property, but delegate to the target's `prototype'. However, yes, there is the (main) difference in respect of supporting TCP (if I understand correctly, since had no time to follow the complete thread) -- return and break/continue jumps to the parent frame instead of working with the function itself.

Lexical `this' is the only similar thing to bound functions, so we should not call => functions as synonym to bound functions. You may say, => function _as well as_ a bound captures `this' lexically, but in contrast with it, it has other features.  In my later analysis, I'll specify them as a new type of functions --  AF (Arrow Function) -- in addition to FE, FD, NFE, BF, etc., with many own features, but not just a syntactic sugar -- neither for FE, nor for BF.

Dmitry



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