Subj : Re: Private Data and Prototype Inheritance
To   : Kevin Lindsey <kevin@kevlindev.com>
From : Brendan Eich <brendan@meer.net>
Date : Fri Jan 09 2004 01:33 pm

Kevin Lindsey wrote:

> but cannot do this:
> 
>     var fancyLine = new FancyLine();
>     fancyLine.x1 = 10.0;
>     fancyLine.y1 = 10.0;
> 
> even though the FancyLine example results in calls to Line's setProperty
> function with reference to the fancyLine object (which previously did have
> private data attached to it).

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

You could wrap, instead, but then you have to make a Line for every 
FancyLine.

Alternatively, you could avoid private data and use property storage. 
Then delegation works as usual.

/be

.