I sympathise with Allen's concern. Implementations might have layering issues as well, especially if Set is mostly self-hosted. We should make it a plain array.
/Andreas On 25 September 2013 22:34, Erik Arvidsson <[email protected]> wrote: > Conceptually it is a set but I don't think anyone cares enough to > oppose this being an array given that it is a cleaner layering of the > spec. > > On Wed, Sep 25, 2013 at 1:07 PM, Allen Wirfs-Brock > <[email protected]> wrote: >> At last weeks TC39 meeting we had consensus that the value of the >> @@unscopable property should be a Set >> https://github.com/rwaldron/tc39-notes/blob/master/es6/2013-09/sept-17.md#53-unscopeable >> >> As I begin to look at implementing this (and the other @@unscopable changes >> from the meeting) I'm not so sure that Set is such a good idea. My basic >> concern is that @@unscopable operates at a very low level of the ES name >> binding resolution mechanism. Set exists at a much higher conceptual level >> of the ES library and (until now) there was nothing in the fundamental >> language semantics of ES that depends upon the existence of a library Set >> object. Now that I have thought about this, it seems fundamentally wrong to >> unnecessarily create such an up-dependency. >> >> I think we will have a cleaner semantics if we continue to treat an >> @@unscopable value as an array-like object for the purpose of accessing its >> property blacklist. Implementations, if they wish, can us2 caching scheme to >> obtain sub-linear time access to an @@unscopable blacklist. >> >> In light of this consideration, does anybody still want to argue that we >> should require an @@unscopable value to be a Set instance? >> >> Allen >> >> _______________________________________________ >> es-discuss mailing list >> [email protected] >> https://mail.mozilla.org/listinfo/es-discuss >> > > > > -- > erik > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
