2012/11/25 Allen Wirfs-Brock <[email protected]> > > On Nov 25, 2012, at 12:41 PM, Tom Van Cutsem wrote: > > > However, with [[HasProperty]] removed, I assume the "in"-operator no > longer triggers the "has" trap when it encounters a proxy, instead doing > the proto-chain-walk itself and calling "hasOwn" on each level. This is OK, > although it introduces an inconsistency with the other proto-chain-walking > algorithms, which stop when encountering a proxy, letting the proxy take > over from that point (this is the case for the "get", "set" and "enumerate" > traps). > > > [[HasProperty]] is replaced with a HasProperty abstract operation (9.3.6) > that indeed makes generic calls to [[HasOwnProperty]] and > [[GetInheritance]] in a loop. This also slightly bothers me. I guess I > convinced my self that an object that wanted to use a non-standard > inheritance path could hide that by reporting its inherited properties to > be own properties. > > I also occasionally find it troubling inheritance semantics are > replicated in three different places [[GetP]], [[SetP]], and HasProperty > and that it is quite possible to get them out of sync. I've come to > accept the replication/possible inconsistency but maybe we really do need > to bring back [[HasProperty]] so that it is possible to consistently > over-ride all three. I'd might be happy to swap > [[Feeze]]/[[Seal]]/i[[sFrozen]]/[[isSealed]] for [[HasProperty]] :-) >
Yes, this is a good point: one must be able to consistently override all inheritance-related operations. Requiring an object with multiple prototypes to report all inherited properties as "own" feels broken. W.r.t. freeze and friends, I thought you were considering a more generic [[GetIntegrity]]/[[SetIntegrity]] operation. Cheers, Tom
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