On 28 July 2011 20:34, David Bruant <david.bru...@labri.fr> wrote: > Le 28/07/2011 19:52, Andreas Rossberg a écrit : >> On 28 July 2011 10:35, David Bruant <david.bru...@labri.fr> wrote: >>> Le 28/07/2011 06:21, Brendan Eich a écrit : >>>> == Handler access to proxies == >>>> >>>> Proxy handler traps need to receive the proxy as a parameter: first, or >>>> last? >>>> >>>> Last allows trap implementors to leave |proxy| off. It's also a compatible >>>> extension to the proposal and its prototype implementations. Putting >>>> |proxy| >>>> last may also steer implementors away from touching proxy, reducing the >>>> bugs >>>> where you infinitely diverge. >>>> >>>> First is more normal-order (proxy, name) and some find it more >>>> aesthetically pleasing. >>>> >>>> Another alternative: the proxy could be "passed" via a data property on >>>> the handler. >>> I think we discussed already the idea of "proxy" being passed as a data >>> property to the handler and came to the conclusion that it may not be a good >>> idea, because it breaks the stratification. If two proxies use the same >>> handler as in [2], then, there is an ambiguity on what the value of this >>> property should be. >> The solution we discussed is to simply use prototypes. That is, share >> handler methods by putting them on a (single) prototype object, and >> have per-proxy instances that carry the individual proxy references >> (or other per-proxy data, for that matter). > This is a pattern that I have seen used by Tom a lot and that I really > like too, but you can't force a user to do that. > So I assume, you would systematically add a base object and use the > argument handler as its prototype? > > --- > // h is a handler object > var p1 = Proxy.create(h); > var p2 = Proxy.create(h); > --- > When a user does this, what does he want? To use the exact same handler > (same object identity)? Or to use the same logic but different internal > properties? > The solution you discussed seems to assume the latter, but who knows? > And how do I implement the former if the proxy spec imposes that the > object I pass internally becomes another object?
I'm not sure I understand what you are asking. The solution I mentioned is purely user-side. There is no magic assumed in the proxy semantics. If you pass the same handler twice, it will be the same handler. If you need proxy-specific state, pass different handlers. If you still want some form of code sharing, use prototypal delegation. > Now that I think about it, it's a bit weird that the proxy API allows to > create several proxies with the same handler (same object identity). > Maybe the API could be reworked in order to prevent it? Maybe > Proxy.create should return the same proxy object if provided the same > handler (p1 === p2, here)? I agree that there probably aren't too many useful examples for using the same handler. However, I also don't see a good reason for disallowing it, nor to require Proxy.create to memoise all handlers. /Andreas _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
