(Pardon the late reply. Catching up.) I'd also go with option 1 (accept that [[Invoke]] changes visible order of side-effects).
Option 2 pollutes the simple interface of [[Invoke]] for compatibility with edge-cases, which, as MarkM points out, are not fully web-compatible anyway. The symmetric operation, i.e. Reflect.invoke(obj, "m", f, args) would also make little sense. Regards, Tom 2013/8/19 Mark S. Miller <[email protected]> > And because it remains open, whereas FF, Safari, and old Opera followed > ES5, the cross-browser web must be compatible with either decision. > > > On Mon, Aug 19, 2013 at 11:15 AM, Mark S. Miller <[email protected]>wrote: > >> More data about whether changing this would break anything: >> >> I reported <https://code.google.com/p/v8/issues/detail?id=691> in May >> 2010. It remains open -- probably because it has caused few actual problems. >> >> >> On Mon, Aug 19, 2013 at 10:44 AM, Allen Wirfs-Brock < >> [email protected]> wrote: >> >>> >>> On Aug 19, 2013, at 9:39 AM, Brandon Benvie wrote: >>> >>> On 8/19/2013 9:33 AM, Allen Wirfs-Brock wrote: >>> >>> thisObj.[[Invoke]](propertyKey, function, argumentList) >>> >>> >>> This could allow [[Invoke]] to trap `call` and `apply`, if propertyKey >>> was allowed to be undefined. >>> >>> >>> I don't really want to get us off the topic WRT to the breaking change >>> issue. But, WRT call/apply here is a couple fragments from a private >>> exchange between TomVC and me: >>> >>> >>> On Jul 30, 2013, at 9:57 AM, Allen Wirfs-Brock wrote: >>> >>> >>> On Jul 30, 2013, at 1:25 AM, David Bruant wrote: >>> >>> ... >>>> >>> This is not enough. >>> this-binding ("proxy.getMonth()" when the target is a Date) is only half >>> of the story. The other half remains unadressed >>> ("Date.prototype.getMonth.call(proxy)"). Exotic objects aren't always used >>> as "this" value. This is exactly Tom's feedback actually. >>> We need the same solution for both cases (this and non-this usage of >>> methods). >>> >>> >>> I also raised this objection and it is what led to the recent update to >>> the virtual object API referenced above. What that change does is make it >>> easier for ES programmer to create proxies that behave in this manner. >>> >>> But, in the end we could not come up with a solution for the >>> Date.prototype.getMonth.call(proxy) issue. The [[Invoke]] MOP >>> operation/trap was added to minimize the actual occurrence of this >>> scenario. You can't use 'call' to force a built-in to operate upon the >>> wrong kind of object. >>> >>> ... >>> >>> >>> Is there a handler semantics with which it can fully work? That's all is >>> needed. >>> >>> >>> The ForwardingHandler semantics is close to what you want. But it still >>> doesn't work the way you would like for direct "call" invocation or for >>> things like Array.isArray. The base issue for either of these is that they >>> don't indirect through the proxy handler and hence the handler doesn't have >>> an opportunity to replace the proxy reference with the target reference. >>> >>> >>> I wonder if we could respecify F.p.call/apply in a manner that would >>> make David's getMonth.call use case work (at least some of the time). >>> >>> [[Invoke]](P, ArgumentsList, Receiver) is current specified such that P >>> must be a property key. What if we modify that so that P can be either a >>> property key or a callable and that when a callable is passed the [[Get]] >>> steps are skipped and P itself is used as the method. >>> >>> Then call/apply could be respecified in terms of [[Invoke]] and >>> ForwardingHandler could do the appropriate handler substitution. >>> >>> Of course, this is only an asymptotically better solution, as it only >>> improves the handler of Proxy objects in the this position. It wouldn't, >>> may itself, fix Array.isArray. >>> >>> >>> Tom's thought were: >>> >>> On Jul 31, 2013, at 3:58 AM, Tom Van Cutsem wrote: >>> >>> While clever, I don't think this will fly, for the reason that many >>> programmers use the explicit `call` syntax particularly so that they can >>> *guarantee* that the method to be invoked is the built-in that they >>> previously stashed away somewhere. >>> >>> If now `F.p.call` is going to delegate the decision of what code is to >>> be executed to the thisArg, that destroys the pattern. >>> >>> I know Mark's SES is full of preamble code where he first obtains >>> references to the actual built-ins, then invokes those built-ins using >>> `call` to make sure he will be executing only the original built-in code, >>> nothing else. >>> >>> >>> These two ideas for [[Invoke]] could be combined (pass both 'f' and 'p' >>> and have call/apply use [[Invoke]]) but it still does't address Tom's >>> concern. >>> >>> Allen >>> >>> _______________________________________________ >>> es-discuss mailing list >>> [email protected] >>> https://mail.mozilla.org/listinfo/es-discuss >>> >>> >> >> >> -- >> Cheers, >> --MarkM >> > > > > -- > Cheers, > --MarkM > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > >
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