Subj : Re: Private Data and Prototype Inheritance
To   : netscape.public.mozilla.jseng
From : Brendan Eich <brendan@meer.net>
Date : Fri Jan 09 2004 01:55 pm

Brendan Eich wrote:

> You can't delegate method calls from an object lacking private data to 
> one having private data

where the method (function, getter, setter) depends on private data to 
do its work

 > , unless the prototype's getter/setter use the
> prototype's privates, which would in general make a pigeon-hole problem 
> (only one prototype, many delegating instances).

I hope this is clear.  It's not a matter of language design, rather of 
engine implementation.  The JSCLASS_HAS_PRIVATE flag is hidden, and you 
can't make a user-defined JSClass anyway, or call JS_GetPrivate or 
JS_SetPrivate from script.

It's still possible to extend native classes, but you'll need either to 
use property (not private data slot) storage in the native base class, 
or else to wrap.

/be

.