[Oops. Actually changing the Subject: this time] [change of Subject: as this reply starts the promised thread]
Hi Lasse, good. That is the direction Dave Herman suggested and which I also find attractive. I have elaborated it at < http://wiki.ecmascript.org/doku.php?id=strawman:magic_proto_property>, which I've also placed on the Agenda for the January EcmaScript meeting. The most surprising punchline is in requirement #4: Object.create(null), creating an object that does not inherit from Object.prototype, also creates an object that does not inherit it’s __proto__, even if that property has not been deleted. With this change, objects-as-stringmaps for objects created by Object.create(null) would avoid the __proto__ hazard, even in contexts where Object.prototype.__proto__ has not been deleted. (FF already acts this way, so my previous message was wrong in claiming that Object.create(null) fails to avoid this platform on all non-IE browsers.) Comments on this proposal appreciated. On Wed, Dec 28, 2011 at 5:26 PM, Lasse Reichstein < reichsteinatw...@gmail.com> wrote: > The biggest problem with __proto__, as I see it, isn't that you can > hit it accidentally, but that even if you know what you are doing, you > can't avoid it (and have to do expensive workarounds). > > It obviously depends on the implementation. In Mozilla > Firefox/*Monkey, __proto__ is an inherited accessor on > Object.prototype (just as __define[SG]etter__). It's not an > own-property and you can shadow it. > > In Chrome/V8, it's an artificial own property on every object, and it > can't be removed, shadowed or ignored. It tries to emulate Safari's > original implementation, but probably fails some details (as your > tests show, they aren't the same). > > I like the Firefox way much better, both as a user and as an > implementor. Since we probably can't get rid of __proto__ totally, I > would cheer if implementations would change to the Mozilla way. > > /L 'entirely my personal opinion'. > > -- Cheers, --MarkM
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