Sorry I'm so excited about this that I just could not read it all before
posting this, my apologies if it's already discussed:
On Monday, 2011-11-14 at 17:04 , Allen Wirfs-Brock wrote:
> > > >
> > > > UnaryExpression :
> > > > class UnaryExpression
> > > > ...
> > > >
> > > > The semantics are:
> > > > 1. if UnaryExpression is undefined or null, return the value of
> > > > UnaryExpression.
> > > > 2. Let obj be ToObject(UnaryExpression)
> > > > 3. Return the result of calling the [[Get]] internal method of obj with
> > > > argument 'constructor'
> > > >
> > >
> > >
> > > Interesting, so 'constructor' will inherit from Object.prototype if
> > > missing from the exemplar. This means
> > >
> > > let Point = class {
> > > x:0,
> > > y,0
> > >
> > > };
> > >
> > > let p = new Point(1, 2);
> > >
> > > will result in p being constructed via the equivalent of new Number(1).
> >
>
> sh*t! I though I'd had a solution for this, but maybe I don't...
>
> If you are really going to define either an object or class exemplar, you
> really need to define a constructor. The object exemplar case actually works
> out ok in this case because the inherited constructor is "called as a
> function", not "as a constructor". So for
>
> let Point = {
> x: 0,
> y: 0
> };
> let p = new Point(1,2);
>
> Is pretty much equivalent to:
> let p = Point <| {};
>
> which may not be exactly what the programmer expected but it is a least in
> the vicinity and yields an object with (inherited) x and y properties.
I think this concern could be easily fixed if `class prototype` was equivalent
of `Class(prototype)` where implementation of Class is following (BTW I don't
propose to use Class function just illustration of what class prototype could
be) :
function Class(prototype) {
function constructor() {
Object.hasOwnProperty(prototype, 'constructor')
let instance = Object.create(prototype);
instance.constructor.apply(instance, arguments);
return instance;
}
constructor.prototype = prototype;
return constructor;
}
As additional benefit this solves issue of shared / frozen constructor
properties of the prototype.
P.S.: I just yesterday I started experimenting with `Class` function in
combination with selfish. _______________________________________________
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