On Tue, Sep 10, 2013 at 6:31 AM, Domenic Denicola <[email protected]> wrote: > Note that determining desired pattern is relevant to the new DOM promises > design (tracking this at > https://github.com/domenic/promises-unwrapping/issues/25). Omitting a few > steps not relevant to the issue under discussion, currently we do: > > - Let `then` be `Get(potentialThenable, "then")`. > - If `IsCallable(then)`, call `then.[[Call]](potentialThenable, (resolve, > reject))`. > > It seems like we'd want to apply the same logic here as we do to `valueOf` > etc., which is what I tried to model this after.
I think the simplest thing would be to replace [[Invoke]] with a [[GetMethod]] trap, and the idiom would then be exactly as above, but change `Get` to `GetMethod`. The last step of Invoke(O, P, args) would be replaced with: 6. Let method = O.[[GetMethod]](P, O). 7. ReturnIfAbrupt(method). 8. If IsCallable(method) is false, throw a TypeError. 9. Return method.[[Call]](O, args). For ordinary objects, [[GetMethod]] would be exactly like [[Get]]. The default proxy.[[GetMethod]] algorithm would be slightly different: it would return a bound function object, bound to the target. tomvc, I'm not sure why [[Has]] followed by [[Invoke]] is worse for double-lifting than [[Get]] followed by [[Call]], but this change would bring us back closer to the latter. Is that sufficient? -j _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
