How to extend the XML object?

[Robin Luscombe]

Hello,

I am interested in defining a function that is available to all XML
objects. I tried the following:

XML.prototype.foo = function() {
// ...
}
var x = <a/>;
x.foo();

However, this results in the following error:

TypeError: Cannot find function foo.

Is it possible to extend XML objects in this way?

Thanks,
Robin

[David P. Caldwell]

It is not currently possible to extends XML objects in any way,
really. The problem is that the XML prototype object is itself an XML
object (of type 'text') and hence assigning a property to it like this
is not allowed (or, more properly, does nothing -- see section 9.1.1.2
of the E4X specification, 2nd edition, available at
http://www.ecma-international.org/publications/standards/Ecma-357.htm).

If it -were- in the future to be possible to extend XML objects in
this way, we'd need an extension, like the special ::function
namespace in Spidermonkey, in order to operate on the prototype and
add methods to that. The ::function namespace is not currently
implemented in Rhino.

-- David P. Caldwell
http://www.inonit.com/

>
> Thanks,
> Robin