Proposal: Concise instance initialisation

Sean Eagan seaneagan1 at
Tue May 24 07:37:19 PDT 2011

On Tue, May 24, 2011 at 9:10 AM, Brendan Eich <brendan at> wrote:
> On May 24, 2011, at 7:02 AM, Sean Eagan wrote:
>>> This conflicts with the existing:
>>> var foo = "bar";
>>> {foo}  // "bar"
>>> {!foo} // false
>> No, just because |{!b}| is current syntax, doesn't mean that |var a = {!b}| is.
> I've been working on syntax lately, and based on that work, I think this goes too far. It requires splitting the grammar in a way that needs greater parsing power than LR(1), e.g. GLR. Unlikely to get by TC39 and implementors.
> It would be better to preclude the ! and ~ prefixes from being used with the {b} shorthand.
> /be

I am definitely a grammar classification noob, so feel free to rake me
over the coals on this if necessary, but how is :

var a = {!b};

... any more difficult to parse than ...

var a = {b};

... both {b} and {!b} and valid blocks, so it is equally as easy to
determine that they are object literals instead, and once inside the
object literal, everything should be peachy I would think.

Sean Eagan

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