Intentional breaking change in ES6 draft spec?

Brendan Eich brendan at
Thu Jun 13 19:53:25 PDT 2013

On Jun 13, 2013, at 7:24 PM, Luke Hoban <lukeh at> wrote:

>>> From: Erik Arvidsson [mailto:erik.arvidsson at] 
>>> This was from back in the days when Google code search was still available and the only hits we found were from test suites.
>>> On Jun 13, 2013 8:54 PM, "Brendan Eich" <brendan at> wrote:
>>> We had some web crawling help, IIRC. We also figured we had time to test and put it back, if needed. Did you find web content using it?
> We haven't done a run yet to look for content using this.  Promising to hear that Google code search didn't hit anything.  I'll see if we can get some data here.


>>>>> Was that an intentional breaking change?  If so, why?
>>> Yes, to simplify and tighten up grammar (and engines). We reckoned that only testsuites counted on this. This was recorded in some meeting notes but I'm not free to dig them up right now.
> Must have missed that discussion.  Doesn't seem a big win for engines or the grammar, as it reduces orthogonality in the grammar wrt variable declarations (I believe this introduces the only place that "var x" is allowed but cannot have an initializer?).

Sure, but note the screwy one-declarator-only restriction. The semantics are too string out too in the existing specs prior to ES6. Inlining is better on both syntactic and semantic grounds.


> Luke  

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