>
>
> perhaps:
>
> `constructor{a: x, b: y), [a1,a2,a3,...arest], c ) : super(arguments[0],
> arguments[1]) {}`
>
> but that means that the special header form must allow arbitrary
> expressions. Are those expression in the parameter scope of the body scope.
>
Yes and yes.
>
> Most importantly, a single constrained expression isn't expressive enough.
> The problem, is that a subclass constructor may need to perform arbitrary
> compelx computations before super newing the its base constructor. For
> example, consider a TypeArray subclass constructor that filters various
> collections passed to to the derived constructor to produce a simple list
> iterator that it passed to the base constructor.
>
Would this work?
class C extends B {
constructor(a, b, c) : super(...gimmeSomeComplexSuperArgsYo(a, b,
c)) {
// ...
}
}
Or using static helper methods, if you prefer:
class C extends B {
constructor(a, b, c) : super(...this.gimmeSomeSuperArgsYo(a, b, c))
{
// ...
}
static gimmeSomeSuperArgsYo(a, b, c) {
// ...
}
}
If being (painfully) explicit is desired, then you could require the "new"
in there:
class C extends B {
constructor() : new super() { }
}
It seems to me that with the proposed design we're going to have to branch
on "new^" continually: if we don't, then the function will always fail if
[Call]'ed and it contains a this-setter.
With the class create expression approach, that branch is taken care of
automatically.
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