D'oh -- of course, you're right. The use case I'm describing wants the proxy,
not the receiver.
Thanks,
Dave
On Oct 16, 2011, at 2:44 PM, David Bruant wrote:
> Le 16/10/2011 23:02, David Herman a écrit :
>> Forgive me that I've not kept track of where we are in the discussion about
>> the additional receiver argument.
>>
>> I think I just found a pretty important use case for the receiver argument.
>> Say you want to keep some information about a proxy object in a Map or a
>> WeakMap, and you want the handler to be able to access that information.
>> Then you're going to need the proxy object to do it.
>>
>> I suppose you can close over the proxy value:
>>
>> var proxy;
>> var handler = { ... proxy ... };
>> proxy = Proxy.create(handler);
>>
>> But then you have to make a fresh handler for each instance.
> There are 2 different things:
> 1) the receiver object.
> This one may only be useful in case of inheritance:
> -----
> var p = Proxy.create(someHandler);
>
> var o1 = Object.create(p);
> var o2 = Object.create(p);
>
> o1.a;
> o2.a;
> -----
> here, both o1 and o2 delegates their "get" to the proxy... so we
> thought. Sean Eagan started a thread which conclusion was based on the
> semantics of [[Get]], you never call the [[Get]] of the prototype, but
> rather its [[GetProperty]] internal. Consequently, you never need the
> receiver. Not even for the tricky case of getter/setter binding. See
> http://wiki.ecmascript.org/doku.php?id=strawman:proxy_drop_receiver
>
> But in my event as property experiment, I have found that I actually
> need that I need the receiver object somewhere to properly implement
> inherited events. I'll post on es-discuss as soon as I'm done to make my
> case and argue back in favor of receiver.
>
>
> 2) the proxy object
> It seems to be what you're describing
> Several arguments and experiments have been made proving that proxy as
> an argument was necessary for all traps. See
> http://wiki.ecmascript.org/doku.php?id=strawman:handler_access_to_proxy
>
>
> I think we're waiting for the November TC39 meeting for decisions to be
> made regarding proxies.
>
> David
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