Allen Wirfs-Brock (2015-01-16T00:24:15.000Z)
d at domenic.me (2015-01-28T19:25:57.426Z)
Rev31 (January 15, 2015) of the ECMAScript 2015 Language Specification is ready for review at http://wiki.ecmascript.org/doku.php?id=harmony:specification_drafts#january_15_2015_draft_rev_31 Changes include: Updated specification to use and support the new built-in subclassing scheme described at: https://github.com/tc39/ecma262/blob/master/workingdocs/ES6-super-construct%3Dproposal.md - Added newTarget parameter to [[Construct]], Reflect.construct, and proxy ‘construct’ trap. - Added NewTarget binding to Function Environment Records and abstract operations/methods of setting and accessing that binding - Redefined [[Construct]] for ordinary ECMAScript functions so “derived” constructors don’t preallocate the new object and bind this. - Changed [[Construct]] for ordinary ECMAScript functions so “derived” constructors will throw if they try to explicitly return a non-object. - Within constructors this binding has TDZ access semantics. - super(...) syntactic form now illegal in Function/GeneratorDeclaration/Expression - super(...) and new super(...) propagates current NewTarget to [[Construct]] call - super(...) binds this value upon return from [[Construct]] call, throw if new already bound - Refactored [[Call]] and [[Construct]] for ordinary ECMAScript functions so they can continue to shared common spec steps. - Updated Generator object instantiation to work with new [[Construct]] design - Refactored Function constructor and GeneratorFunction to share a common abstract operation based definition - Every built-in constructor changed to merge object allocation and initialization code. In some cases (eg, TypedArray and Promise) significant refactoring of allocation and initialization logic. - Updated [[Construct]] of Bound functions to handle newTarget parameter. - Several of the above items are tentative because they still lack full TC39 discussion and review. The following are particularly tentative: - restrictions on where super(...) is allowed may change - new supper(...) might go away or change - Support for the new.target access syntax (yellow highlight in spec text) is speculative and may move to ES7 and/or change Other changes - Merged AllocArrayBuffer and SetArrayBufferData into single abstract operation - %TypedArray%.of now requires that its this value is a valid Typed Array constructor - Replaced “moduleId” with “sourceCodeId” and eliminated most usage of such ids in module related abstract operations - Some tweaking of Language Overview in 4.2 - A new document title - Resolved bugs: 3543-3527, 3524-3523, 3520, 3517-3516, 3514-3511, 3501-3496, 3494-3479, 3310, 3229, 3136, 2865, 2536, 2495, 2179