On May 31, 2012, at 2:52 AM, T.J. Crowder wrote:
> I'm worried this looks a lot like `with` -- with the same issues.
Nooooo. No.
This does not involve the object with the scope chain in any way.
> Is the idea that unqualified references would be _required_ to be properties
> of the object in question? So
>
> o.{
> a.b = 6;
> c.f();
> };
>
> ...would work, but
>
> o.{
> a.b = foo;
> c.f();
> };
>
> ...would throw (assuming there is no `foo` property)?
No. The object is used for the (syntactically restricted, i.e., non-expression)
LHS, but not the RHS expression. The object is not added to the scope chain.
> I keep meaning to propose a new `with` (different keyword, obviously) that
> solves the `with` issues by using a leading dot -- but I wanted to lurk a
> while beforehand, can't imagine it's an original thought (esp. as I used
> _some_ language in the 90s that did that).
You're thinking of VB. I agree it was a better design than JS's `with`. But
it's unfortunately a non-starter for adding to JS, because it introduces a new
ASI hazard:
with (obj) {
foo() // no semi
.bar = 12
}
Dave
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