ES6 plans: Difference between revisions

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ES6 plans (view source)

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-== Harmony infrastructure ==
+{{OutdatedSpiderMonkey}}
-* New SM version number
-* Opt-in via type="text/ecmascript;version=6" or whatever - [https://bugzilla.mozilla.org/show_bug.cgi?id=694107 bug 694107]
-* Per-script opt-in syntax ('use harmony;' or whatever)
-* Opt-in via HTTP header?
-* Whole-page opt-in via HTML feature?
-== Modules ==
-[http://wiki.ecmascript.org/doku.php?id=harmony:modules harmony:modules]
-Modules are [https://bugzilla.mozilla.org/show_bug.cgi?id=568953 bug 568953].
-* <code>module</code> syntax, scoping semantics, module objects
-* <code>import</code> syntax
-* <code>from "url"</code> syntax
-* Hook up <code>from "url"</code> and async module loading to Gecko
-* [http://wiki.ecmascript.org/doku.php?id=harmony:module_loaders Module loaders]
-== New APIs that are in modules ==
-* [http://wiki.ecmascript.org/doku.php?id=harmony:modules_standard Reorganize the standard library into modules]
-* [http://wiki.ecmascript.org/doku.php?id=harmony:private_name_objects Private name objects] - [https://bugzilla.mozilla.org/show_bug.cgi?id=694127 bug 694127]
-* A few functions for [http://wiki.ecmascript.org/doku.php?id=harmony:iterators iterating over object properties]
 == New and improved builtin APIs ==
-Most of this stuff does not need to touch a lot of code. Pretty good fodder for newbies.
+Most of this stuff does not need to touch a lot of code. None of it requires a Harmony opt-in. This is great stuff for new contributors to start work on.
 * [http://wiki.ecmascript.org/doku.php?id=harmony:simple_maps_and_sets Simple Maps and Sets] - The spec is incomplete but I will be landing what's there now in [https://bugzilla.mozilla.org/show_bug.cgi?id=697479 bug 697479].
 * [http://wiki.ecmascript.org/doku.php?id=harmony:binary_data Binary data] - [https://bugzilla.mozilla.org/show_bug.cgi?id=578700 bug 578700]
 * New reflection methods [http://wiki.ecmascript.org/doku.php?id=harmony:extended_object_api Object.getPropertyDescriptor, Object.getPropertyNames]
-* Two more methods are proposed here: [strawman:extended_object_api http://wiki.ecmascript.org/doku.php?id=strawman:extended_object_api]
 * Number.[http://wiki.ecmascript.org/doku.php?id=harmony:number.isfinite isFinite], [http://wiki.ecmascript.org/doku.php?id=harmony:number.isnan isNaN], [http://wiki.ecmascript.org/doku.php?id=harmony:number.isinteger isInteger], and [http://wiki.ecmascript.org/doku.php?id=harmony:number.tointeger toInteger]
 * String.prototype.[http://wiki.ecmascript.org/doku.php?id=harmony:string.prototype.repeat repeat], [http://wiki.ecmascript.org/doku.php?id=harmony:string_extras startsWith, endsWith, contains, toArray]
-* New reflection API that complements proxies: [harmony:reflect_api http://wiki.ecmascript.org/doku.php?id=harmony:reflect_api]
+* New reflection API that complements proxies: [http://wiki.ecmascript.org/doku.php?id=harmony:reflect_api harmony:reflect_api]
-* [http://wiki.ecmascript.org/doku.php?id=harmony:egal Object.is, isnt]
+* [http://wiki.ecmascript.org/doku.php?id=harmony:egal Object.is]
-* [http://wiki.ecmascript.org/doku.php?id=harmony:more_math_functions More math functions] - Proposed are: Math.log10, log2, log1p, expm1, cosh, sinh, tanh, acosh, asinh, atanh, hypot, trunc, sign; perhaps gamma and erf; and perhaps randomInt(n).
+* [http://wiki.ecmascript.org/doku.php?id=harmony:more_math_functions More math functions] - Proposed are: Math.log10, log2, log1p, expm1, cosh, sinh, tanh, acosh, asinh, atanh, hypot, trunc, sign; perhaps gamma and erf; and perhaps randomInt(n). See [https://bugzilla.mozilla.org/show_bug.cgi?id=717379 bug 717379].
 * ES6 will spec that [http://wiki.ecmascript.org/doku.php?id=harmony:random-er Math.random] does not share state across multiple globals.
 == New syntax (stuff that affects the front end and/or bytecode) ==
-* [http://wiki.ecmascript.org/doku.php?id=harmony:egal <code>is</code> and <code>isnt</code> operators]
+This stuff isn't terribly hard either, for the most part.
 * [http://wiki.ecmascript.org/doku.php?id=harmony:iterators for-of loops] - [https://bugzilla.mozilla.org/show_bug.cgi?id=699565 bug 699565] - This is I'd say better than half done. It was easy. XPConnect must be updated so that arraylike XPCOM objects cooperate with for-of.
 * [http://wiki.ecmascript.org/doku.php?id=harmony:parameter_default_values Parameter default values]
 * [http://wiki.ecmascript.org/doku.php?id=harmony:rest_parameters Rest parameters] - [https://bugzilla.mozilla.org/show_bug.cgi?id=574132 bug 574132]
-* [http://wiki.ecmascript.org/doku.php?id=harmony:spread Spread operator] - [https://bugzilla.mozilla.org/show_bug.cgi?id=574130 bug 574130] - The operator can appear in two places: function calls and array literals. I think the implementation will be
+* [http://wiki.ecmascript.org/doku.php?id=harmony:spread Spread operator] - [https://bugzilla.mozilla.org/show_bug.cgi?id=574130 bug 574130] - The operator can appear in two places: function calls and array literals. Maybe two bugs would make sense.
 * [http://wiki.ecmascript.org/doku.php?id=harmony:proper_tail_calls Proper tail calls]
 * [http://wiki.ecmascript.org/doku.php?id=harmony:object_literals Extensions to object literal syntax]
 * [http://wiki.ecmascript.org/doku.php?id=harmony:classes Classes]
-* [http://wiki.ecmascript.org/doku.php?id=harmony:quasis Quasi-literals]
+* [http://wiki.ecmascript.org/doku.php?id=harmony:quasis Quasi-literals] [https://bugzilla.mozilla.org/show_bug.cgi?id=688857 Bug 688857]
 * [http://wiki.ecmascript.org/doku.php?id=harmony:pragmas Pragmas]
+== Updating SpiderMonkey extensions to the ES6 spec ==
-== Updating SpiderMonkey extensions to Harmony ==
+We've implemented a ton of stuff, dating back years, that is going to be in ES6 but in a slightly different form.
 === Direct proxies ===
-There is a ton of verbiage here and it is still under active development.
+There is a ton of verbiage here and it is still under active development. Still, I think it should be pretty easy to implement. We already have the forwarding code. We can keep <code>Proxy.create</code> and <code>createFunction</code> without a lot of extra effort.
+[https://bugzilla.mozilla.org/show_bug.cgi?id=703537 Bug 703537].
 * http://wiki.ecmascript.org/doku.php?id=harmony:direct_proxies
@@ Line 79: / Line 58: @@
 * TC39 is specifying that reading a let-variable before it is initialized is an error, which will be a separate bug.
 * <code>const</code> - [https://bugzilla.mozilla.org/show_bug.cgi?id=611388 bug 611388]
-* Block functions - [https://bugzilla.mozilla.org/show_bug.cgi?id=585536 bug 585536]
+* Block functions - [https://bugzilla.mozilla.org/show_bug.cgi?id=585536 bug 585536] (note - opt-in only, still banned in ES5 strict mode)
 * [http://wiki.ecmascript.org/doku.php?id=harmony:destructuring Destructuring]
+* Per loop iteration binding of let/const.
+== Harmony infrastructure ==
+Some minimal steps here are a prerequisite to doing the features that require a Harmony opt-in: modules and import, block-scoped functions, <code>typeof null</code>, and lexical scoping of names declared at toplevel.
+* New SM version number - This is enough to get started on harmony features with only shell tests.
+* Opt-in via type="text/ecmascript;version=6" or whatever - [https://bugzilla.mozilla.org/show_bug.cgi?id=694107 bug 694107]
+* Per-script opt-in syntax ('use harmony;' or whatever)
+* Opt-in via HTTP header?
+* Whole-page opt-in via HTML feature?
+== Modules ==
+[http://wiki.ecmascript.org/doku.php?id=harmony:modules harmony:modules]
+Modules are [https://bugzilla.mozilla.org/show_bug.cgi?id=568953 bug 568953].
+* <code>module</code> syntax, scoping semantics, module objects
+* <code>import</code> syntax
+* <code>from "url"</code> syntax
+* Hook up <code>from "url"</code> and async module loading to Gecko
+* [http://wiki.ecmascript.org/doku.php?id=harmony:module_loaders Module loaders]
+With a Harmony opt-in, programs get very different global binding behavior. The bindings are no longer shared with the global object's properties. This is a major change.
+== New APIs that are in modules ==
+* [http://wiki.ecmascript.org/doku.php?id=harmony:modules_standard Reorganize the standard library into modules]
+* [http://wiki.ecmascript.org/doku.php?id=harmony:private_name_objects Private name objects] - [https://bugzilla.mozilla.org/show_bug.cgi?id=645416 bug 645416]
+* A few functions for [http://wiki.ecmascript.org/doku.php?id=harmony:iterators iterating over object properties]
-== Mistakes ==
+== Incompatible changes ==
-Harmony will include a handful of unnecessary breaking changes that can't be detected statically. Oh well.
+Harmony may change some ES1-5 behavior, if it empirically turns out to be doable without breaking the Web.
 * [http://wiki.ecmascript.org/doku.php?id=harmony:completion_reform Change how eval decides which value to return]
 * typeof null == "null" with Harmony opt-in - [https://bugzilla.mozilla.org/show_bug.cgi?id=651251 bug 651251]