[es7] implement |do| expressions proposal

src/flag-definitions.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file defines all of the flags.  It is separated into different section,
 // for Debug, Release, Logging and Profiling, etc.  To add a new flag, find the
 // correct section, and use one of the DEFINE_ macros, without a trailing ';'.
 //
 // This include does not have a guard, because it is a template-style include,
 // which can be included multiple times in different modes.  It expects to have
@@ skipping 169 matching lines @@
 DEFINE_BOOL(strong_this, true, "don't allow 'this' to escape from constructors")
 
 DEFINE_BOOL(es_staging, false, "enable all completed harmony features")
 DEFINE_BOOL(harmony, false, "enable all completed harmony features")
 DEFINE_BOOL(harmony_shipping, true, "enable all shipped harmony fetaures")
 DEFINE_IMPLICATION(harmony, es_staging)
 DEFINE_IMPLICATION(es_staging, harmony)
 
 DEFINE_BOOL(legacy_const, true, "legacy semantics for const in sloppy mode")
 
+DEFINE_BOOL(do_expression_parsing, false, "do expression parsing")

[rossberg, 2015/10/12 13:52:40]

No reason not to call this harmony_do_expressions, I think.

[caitp (gmail), 2015/10/12 18:23:00]

Hmm, I think "harmony" might be a bit of a stretch until other implementors are
on board, and I didn't want to give the impression that it would be safe for
people to start using it in node.js apps or something.

Do we really want to change the name?

[rossberg, 2015/10/13 10:44:32]

It's in the TC39 process, so it's adequate. We have consistently used harmony
for those. So yes, please change.

(As for impressions, we have repeatedly stated that it is _not_ safe to use
features that are not implied by the global --harmony flag, for all sorts of
reasons. Anybody who does so is on their own.)

[caitp (gmail), 2015/10/13 15:05:59]

Done

+
 // Features that are still work in progress (behind individual flags).
 #define HARMONY_INPROGRESS(V)                                         \
   V(harmony_modules, "harmony modules")                               \
   V(harmony_regexps, "harmony regular expression extensions")         \
   V(harmony_proxies, "harmony proxies")                               \
   V(harmony_unicode_regexps, "harmony unicode regexps")               \
   V(harmony_tolength, "harmony ToLength")                             \
   V(harmony_reflect, "harmony Reflect API")                           \
   V(harmony_destructuring, "harmony destructuring")                   \
   V(harmony_default_parameters, "harmony default parameters")         \
@@ skipping 906 matching lines @@
 #undef DEFINE_ALIAS_FLOAT
 #undef DEFINE_ALIAS_ARGS
 
 #undef FLAG_MODE_DECLARE
 #undef FLAG_MODE_DEFINE
 #undef FLAG_MODE_DEFINE_DEFAULTS
 #undef FLAG_MODE_META
 #undef FLAG_MODE_DEFINE_IMPLICATIONS
 
 #undef COMMA