Nannying (was: Array comprehension syntax)

Brendan Eich brendan at
Tue Sep 25 13:30:13 PDT 2012

Allen Wirfs-Brock wrote:
> I think we should go the all AssignmentExpression route.  It avoid ArrayLiteral-like comma confusion in all three positions.  It is also a simpler set of rules to teach and remember. 

It's different from the statement forms, though.

Again, this is a non-issue in practice. Nobody writes comma expressions 
in those places.

>    Finally, it leave open the future possibility of ArrayLiterals that have comprehensions in element positions. (not that I'm recommending this...) 

Why wouldn't comprehensions be allowed in ArrayLiteral element 
positions? That falls out of any grammar that puts comprehensions at 
PrimaryExpression precedence, where they must be.

This is not a huge deal and I defer to Jason as champion-apparent, but 
it does seem worth agreeing on the same Expression non-terminal for if 
and for conditions in both statements and comprehensions, or finding a 
better reason to change in the latter.


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