[es7] implement |do| expressions proposal

src/flag-definitions.h

Index: src/flag-definitions.h
diff --git a/src/flag-definitions.h b/src/flag-definitions.h
index 9f350a150fcd575cb5da944282d9a22a537b3652..0a225d7770e8b02bfb31c4b2e3df679d59672aba 100644
--- a/src/flag-definitions.h
+++ b/src/flag-definitions.h
@@ -187,6 +187,8 @@ 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")                               \