On Jun 25, 2014, at 10:27 AM, Erik Arvidsson wrote: > Allen, > > > If propKey is the string value "__proto__" > > Do we want to allow "__\u0070roto__" or not? For "use strict" we made it > clear that no escape sequences are allowed. I think we should follow that > route unless it makes implementation and/or speccing too hard.
I think the usual rules should apply. LiteralPropertyName is either an IdentifierName or a StringLiteral. http://people.mozilla.org/~jorendorff/es6-draft.html#sec-names-and-keywords says the escaped and non-escaped code points are equivalent within an IdentifierName. http://people.mozilla.org/~jorendorff/es6-draft.html#sec-static-semantics-sv-s-and-cv-s says the the SV of is the same for a string containing non-escaped code points and a string containing escapes for the same code points. That means that {__proto__: something}, {__\u0070roto__: something}, {"__proto__": something}, and {"__\u0070__": something} should all mean the same thing and if Annex B is being implemented that means they all do a [[SetPrototypeOf]]. I think "use strict" is a special care where we were trying to simulate what we would allow in a statement composed of reserved words and escapes are now allowed in keywords. http://people.mozilla.org/~jorendorff/es6-draft.html#sec-reserved-words Allen > > > On Wed, Jun 25, 2014 at 11:21 AM, Allen Wirfs-Brock <al...@wirfs-brock.com> > wrote: > yes, this is covered by > http://people.mozilla.org/~jorendorff/es6-draft.html#sec-__proto__-property-names-in-object-initializers > > > __proto__ only has special meaning within a production: > > PropertyDefiniton : PropertyName ":" AssignmentExpression > > and when PropertyName is not a ComputedPropertyName. > > All other PropertyDefinition forms that have __proto__ as the property name > (whether literally or as a ComputedPropertyName) just define ordinary > properties with the name "__proto__". > > The current non-duplicated name restriction made it illegal to have more than > one __proto__ : something property definitions in an object literal. Because > __proto__: something is a special form with its own semantics I think we > should continue to make it illegal to have more than one of them, even when > we relax the duplicate rule for regular property definitions. > > Allen > > > On Jun 25, 2014, at 8:09 AM, Erik Arvidsson wrote: > >> If I recall correctly the intent was that __proto__ was special syntax for >> setting the [[Prototype]]. So only three following cases are setting the >> [[Prototype]] >> >> {__proto__: object} >> {'__proto__': object} >> {"__proto__": object} >> >> Other combinations set an own property: >> >> {['__proto__']: object} >> {'__\u0070roto__]: object} >> {__proto__() {}} >> var __proto__; >> {__proto__} >> {get __proto__() {}} >> {set __proto__(x) {}} >> >> Combining these leads to confusing code (so don't do that) but the semantics >> is clear. >> >> >> On Wed, Jun 25, 2014 at 9:27 AM, Andy Wingo <wi...@igalia.com> wrote: >> On Wed 25 Jun 2014 15:19, Andy Wingo <wi...@igalia.com> writes: >> >> > Hi, >> > >> > On Fri 20 Jun 2014 15:16, "Mark S. Miller" <erig...@google.com> writes: >> > >> >> On Fri, Jun 20, 2014 at 1:48 AM, Andy Wingo <wi...@igalia.com> wrote: >> >> > >> >> > There is one change: >> >> > >> >> > ({ foo: 3, get foo() { return 4 } }) >> >> > >> >> This is not allowed with current sloppy mode. >> >> >> >> Yes, good catch. This is a change, and it is now allowed. >> > >> > What about: >> > >> > ({ get __proto__() {}, __proto__: foo }) // (1) >> > >> > Does this end up setting the prototype of the result? Would it if there >> > were a setter? >> > >> > Likewise: >> > >> > ({ __proto__: foo, get __proto__() {} }) // (2) >> > >> > This one is kinda similar: >> > >> > ({ ['__proto__']: 34, __proto__: foo }) // (3) >> >> And another one: >> >> ({ get __proto__() {}, __proto__: foo, set __proto__(x) {} }) >> >> Does the resulting accessor have a setter and a getter, or just a >> setter? I would think just a setter, in the same way that this one >> would only have a setter: >> >> ({ get qux() {}, qux: foo, set qux(x) {} }) >> >> Andy >> >> >> >> -- >> erik >> _______________________________________________ >> es-discuss mailing list >> es-discuss@mozilla.org >> https://mail.mozilla.org/listinfo/es-discuss > > > > > -- > erik
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