Callable objects protocol

[Isiah Meadows]

Edit: the wrapper needs to be a function, so ignore that last email. It's wrong.

-----

Isiah Meadows
contact at isiahmeadows.com
www.isiahmeadows.com

On Tue, Dec 4, 2018 at 2:14 PM Isiah Meadows <isiahmeadows at gmail.com> wrote:
>
> BTW, there are proxies [1], and one of the proxy hooks is to intercept
> calls [2].
>
> [1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy
> [2]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/apply
>
> Your "callable object" proposal would be literally as simple as this
> to implement:
>
> ```js
> const callable = Symbol.for("callable")
> const handler = {
>     apply(target, thisArg, argsList) {
>         return Reflect.apply(target[callable], thisArg, argsList)
>     },
> }
> function makeCallable(obj) { return new Proxy(obj, handler) }
>
> // Your example, ported
> const obj = makeCallable({
>     [callable]: function (...args) { return this[Symbol.for('value')] },
>     [Symbol.for(''value')]: 'value',
> })
>
> assert(obj() === 'value')
> obj[callable] = () => 1
> assert(obj() === 1)
> ```
>
> -----
>
> Isiah Meadows
> contact at isiahmeadows.com
> www.isiahmeadows.com
> On Tue, Dec 4, 2018 at 12:02 PM Sultan <thysultan at gmail.com> wrote:
> >
> > Something along the lines of Symbol.iterator protocol for defining callback objects i.e: Symbol.callable:
> >
> > const obj = {
> >     [Symbol.callable]: function (...args) { return this[Symbol.for('value')] },
> >     [Symbol.for(''value')]: 'value',
> > }
> >
> > assert(obj() === 'value')
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