One concern might be that we probably cannot make arrow notation (if
we introduce it) a primary expression, and it might be confusing if
they have different precedence.
I also think it is easier to parse for the human reader when he sees
(function f() { ... })()
instead of
function f() { ... }()
especially when this occurs as a statement. (Mh, actually, could we
even distinguish between function declerations and expression
statements starting with a function expr in LALR(1), without heavy
grammar transformation?)
/Andreas
On 20 October 2011 01:20, Brendan Eich <bren...@mozilla.com> wrote:
> On Oct 19, 2011, at 3:29 PM, Allen Wirfs-Brock wrote:
>
> On Oct 19, 2011, at 2:53 PM, Brendan Eich wrote:
>
> On Oct 19, 2011, at 8:16 AM, Allen Wirfs-Brock wrote:
>
> Function expressions were added in ES3. Were they just added at the wrong
> place in the grammar?
>
> Thanks for raising this, I keep forgetting to.
> Oddly enough, SpiderMonkey always had them (prior to ES3 even being drafted)
> as PrimaryExpressions. No one can observe the difference, as you note.
> Either way, one can write
> var fun_member = function () {}.member;
> On aesthetic grounds, I would prefer the grammar to make function
> expressions primary.
>
> Good, I want to make that change because for semantic specification purposes
> FunctionExpression works better as PrimaryExpression.
> I just wanted to make sure, before I make the change, that there wasn't some
> grammatical subtlety I was overlooking
>
> Toy grammar (| is meta, other punctuators after the : are concrete):
> E: ME
> ME: PE | FE | ME [ E ] | ME . ID | ...
> PE: ( E ) | ...
> and there's no way that ME -> FE would be reduced where ME -> PE -> FE was
> not possible, *and* there are no PE occurrences on the RHS of a production
> whose LHS is *not* ME, then FE can move "down" one precedence level from
> being the sole RHS part of ME, to being the sole RHS of PE.
> (Lotta abbreviation there, sorry.)
> Trivial search shows PrimaryExpression occurs in only one RHS, as the sole
> RHS part produced from MemberExpression.
> /be
>
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>
>
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