[Javascript] custom extension of Array object

[james]

At 02:23 15/04/2005 +0200, you wrote:
>On 4/14/05, james <james at southspace.org> wrote:
> > At 19:22 14/04/2005 +0200, you wrote:
> >
> > is there a difference between setting the prototype of the object and
> > setting the prototype of the constructor function??.
>
>Yes certainly. You see, JavaScript has first class functions. First
>class functions means that functions need to inherit from the Function
>object, not the Object object. Constructors are just special cases of
>functions that are called using the new keyword. Where does this put
>the prototype property?
>
>Let's have a look at how JavaScript inheritance works. All objects
>have a prototype object. Let's call this the [[prototype]] property.
>Each time you do a member lookup, it does something vaguely like this:
>
>  1. Set the this object to the current object.
>  2. Search for the property on the current object.
>  3. If found, return that property.
>  4. If not found, set the current object to the [[prototype]] property
>  5. If current object is null, return undefined.
>  6. Otherwise repeat from 2.
>
>Each object will have it's [[prototype]] propety defined at creation
>time. An engine might provide direct access to [[prototype]], like the
>__proto__ propery in SpiderMonkey.
>
>Constructors both need their own [[prototype]] to make them inherit
>from Function and need to be able to define the prototype object for
>their instances. So, the solution is to in this case have two separate
>properties - one you inherit your function-ness from (named
>[[prototype]]), one you let your instances inherit from (named
>prototype). In other words, when you create a new instance, it's
>[[prototype]] property will be assigned the value of the prototype
>property of it's constructor.

Thanks a bunch for this helpful answer. it took a while to understand this, 
but it makes sense.

James