I am wondering if you discussed the typeof null proposal?
On Thu, Jul 28, 2011 at 9:46 PM, Andreas Rossberg <[email protected]> wrote: > On 28 July 2011 20:34, David Bruant <[email protected]> wrote: >> Le 28/07/2011 19:52, Andreas Rossberg a écrit : >>> On 28 July 2011 10:35, David Bruant <[email protected]> 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 > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
