Le 19/12/2012 17:34, Brandon Benvie a écrit :
Also note that none of these properties are currently accessors so no
one has come to rely on being able to extract their getters. So
introducing them with neutered accessors would not have an impact on
existing code.
I fully agree. I wasn't really worried about backward compat.
On Wednesday, December 19, 2012, Brandon Benvie wrote:
It only has to be a handful of accessors, no? I was thinking
basically of just the few things on the global object that need
this treatment. location, document, window, navigator, maybe a few
others?
Very good point.
We're not redefining what [Unforgeable] means, but only what it means
for WindowProxy objects, so that's very few properties in the end.
And location is the only one with a setter, so we're mostly just
talking about getters on the global object. Since it's the global
object, you could just call the getter directly and `this` will
implicitly be the correct receiver when called inside the context.
I always use strict mode, so it wouldn't work for me. But since these
getter/setter are special, I wouldn't be shocked if they were bound
functions.
So the remaining situations in which it's difficult are in the
parent frame when you want to do this one of the handful of
properties that have this treatment.
An option that might have uses in other places as well is a kind
of primitive version of call, bind, and apply that have the null
prototype, frozen treatment. They could be singletons over the
entire runtime, across realms, and be attached to any function in
any realm (including these accessors) without leaking anything.
I think that was what Brendan called "null realm". It has the problem
that if someone adds new things to Function.prototype or
Object.prototype, your "null realm" getters/setters wouldn't benefit
from it.
David
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