On Wed, Apr 30, 2014 at 5:17 PM, Allen Wirfs-Brock <[email protected]>wrote:
> Where do you find the spec incomplete WRT @@unscopable. My recollection > was that it was all resolved and fully specified and that I was relatively > happy with the outcome. > I thought so too but now that I look at it I cannot find where we Get the @unscopable list out of the with expression object. As far as I can tell unscopables is never populated. http://people.mozilla.org/~jorendorff/es6-draft.html#sec-with-statement-runtime-semantics-evaluation http://people.mozilla.org/~jorendorff/es6-draft.html#sec-newobjectenvironment > > Allen > > On May 1, 2014, at 3:00 AM, Erik Arvidsson <[email protected]> > wrote: > > This was never resolved and the spec is incomplete here > > On Wed Sep 25 2013 at 6:17:32 PM, Allen Wirfs-Brock <[email protected]> > wrote: > >> So here is another concern, about the scheme we agreed to last week. >> >> It needs to match a found own property against the possibility of an own >> @@unscopable property on the same object and that object may be somewhere >> up the inheritance chain of the actual with object. The means that >> [[HasProperty]]/[[Get]]/[[Set]] can not be used to do those resolve >> binding in an ObjectEnvironmentRecord because they don't tell us where the >> property was found. Instead, ObjectEnvironmentRecord needs to reimplement >> its own property lookup using [[GetOwnProperty]] and [[GetInheritanceOf]]. >> However, if the with object is a proxy that means we may be bypassing the >> actual inheritance mechanism implemented by the Proxy's 'has'/'get'/'set' >> traps and that could introduce observable semantics irregularities. >> >> Specifying the duplicated lookup is doable but a pain. That and the >> semantic issues WRT proxies makes me a lot less comfortable with the added >> complexity of supporting @@unscopable. >> >> Allen > > > -- erik
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