Somebody asked me what the main differences are w.r.t. the existing catch-all proposal:
The main similarity: like the existing catch-all proposal, our proxy proposal separates the traps from the object being trapped (i.e. both propose the use of a separate "handler" object). The main difference: the proxy proposal only enables catch-alls for special, empty "proxy" objects. In the existing catch-all proposal, there is still the notion of "activating" or "deactivating" catch-alls on existing objects, which leads to issues such as whether or not the catch-all should trigger on existing properties. Also, from a security POV this has the bad property that any object that has a reference to an object can all of a sudden decide to take control over the behavior of that object. Our proxy proposal does not allow this. The other main difference is that the proxy proposal details how proxies interact with the new ES5 concepts of "frozen", "sealed" and "non-extensible" objects, and with a host of other language features (e.g. instanceof, ===, typeof, the Object.* introspection methods, ...) Cheers, Tom On Mon, Dec 7, 2009 at 4:11 PM, Tom Van Cutsem <[email protected]> wrote: > Dear all, > > Over the past few weeks, MarkM and myself have been working on a proposal > for catch-alls for ES-Harmony based on proxies. I just uploaded a strawman > proposal to the wiki: > > http://wiki.ecmascript.org/doku.php?id=strawman:proxies > > Any feedback is more than welcome. Note that the proposal is quite lengthy, > which is mostly due to the fact that it also includes a detailed semantic > specification of proxies (in ES5-spec-style) in addition to just its API > description. If you're not interested in the specification details, you can > skip the section named "Semantics". > > Cheers, > Tom >
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