On 8 November 2011 20:46, Mark S. Miller <erig...@google.com> wrote: > In general, for an object to be defensive, much of the surface reachable > from it by transitive prototype and reflective property traversal should > usually be frozen, and at least non-extensible. This is possible to express > in ES5 > <http://code.google.com/p/google-caja/source/browse/trunk/src/com/google/caja/ses/startSES.js#623>, > but inconvenient and expensive. That's why I have been advocating better > defensive abstractions for ES6: "const functions", "const classes", > "traitsjs" or its syntactic derivatives, etc. > Nevertheless, I see your point. Many defensive ES5 abstractions will be less > defensive than this. If I understand you correctly, your point is > specifically about the [[Call]] and [[Construct]] traps.
Yes. Existing code has no reason to bother making functions non-extensible if all it does is calling them. Proxy.attach fundamentally breaks that (so far correct, AFAICT) assumption. > Perhaps we should > be more conservative here, without necessarily backing away from the whole > Proxy.attach idea? Disallowing attaching to functions with your own call/construct traps would be the minimal restriction, I think. But maybe there is something cleaner. /Andreas _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
