arrows and a proposed softCall

[Angus Croll]

I actually agree. I included non-this methods only because reading through
this thread I got a  feeling that there was some consensus that they be
treated differently. More than happy to not do that.

On Mon, Jun 4, 2012 at 8:16 AM, Andreas Rossberg <rossberg at google.com>wrote:

> On 3 June 2012 20:13, Angus Croll <anguscroll at gmail.com> wrote:
> > Not suggesting that arrow functions be special cased or that they ignore
> > |thisArg|. I'm suggesting for all relevant cases (=>, bind and no
> |this|) we
> > only throw an error on call/apply if the |thisArg| is non null.
>
> That would not only be a breaking change, as Brendan pointed out. More
> importantly, it would also not be something you truly want. Consider
> this piece of code:
>
>  function C(x) { this.x = x }
>  C.prototype.f = function() { return this.x }
>  C.prototype.g = function() { return this.f() * 2 }
>  C.prototype.h = function() { return 41 }
>
>  let o = new C(21)
>  foo(o, [o.f, o.g, o.h])
>
> where
>
>  function foo(o, funs) {
>    // ...
>    for (let f of values(funs)) {
>      result += f.call(o)
>    }
>  }
>
> According to your suggestion, foo would throw. But there is no actual
> reason why foo should care that h is a constant method. That's an
> implementation detail. Why should the caller have to jump through
> hoops to account for implementation details of the callee?
>
> I think there is a misconception here is that this-oblivious
> methods/functions are something _different_ from "normal"
> methods/functions. They aren't. They are just a _special case_ of
> normal methods/functions. Just like functions that ignore any other
> parameter. Consequently, you don't usually want to treat them
> differently. I claim that code that tries has a 98% likelihood of
> being broken -- or at least of smelling rather bad.
>
> /Andreas
>
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