Complete Minimal Classes
khs4473 at gmail.com
Sun Apr 8 20:02:07 PDT 2012
> I always disliked that some functions in ECMAScript 5 can be invoked as
> either a function or a constructor. What would you want an entity Foo for
> that can be invoked in two ways? E.g.:
> new Foo(...)
Maybe Brendan can answer that one? : )
Seriously, though, it's a fair question. My first response is that since
the Chapter 15 "classes" exhibit this behavior, we should be able to fully
express it in a class syntax.
But beyond that, how should we deal with this situation? We could make
classes *not* implement [[Call]], but that would mean we'd have functions
that didn't implement [[Call]], which is (AFAIK) truly novel and perhaps a
little bizarre. I don't see that happening, but I could be wrong.
So if [[Call]]/[[Construct]] duality is a fact, how *should* we deal with
1) Ignore the possibility of the constructor being [[Call]]ed. This is
the typical response, because it's the easiest. It's also the most
2) Use a best-effort approximation to detect a [[Call]] as in:
3) Separate the two behaviors into separate bodies, with a reasonable
default for the [[Call]] operation.
I think (3) makes the most sense. What do you think?
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