>>I do not believe that you can model a framework in advance.
>
>Of course you can model it, but that doesn't mean you'll never change the model (or, more frequently, its implementation).
>
Yes Mark you're right. You can model it, but implementing a full framework in one shot seems awfully difficult. My point was to emphasize pragatism.


>> if you framework does not work right, and you do not know that in advance, you are in trouble, because you cannot change parents.<
>
>I'm not sure what you mean, here. Certainly, changing interface can mean cascading changes to the app code, and that's a pain. You really do want to make as sure as possible that your public methods (and the parameters they take) stay the same. But beyond that, you're free to change the implementation as much as you want. One of the nicest things in the world is to fix a bug in the framework and have that fix automatically cascade to your apps.

Those are the nice bugs. But more often than not, when you are a beginner, you get conceptual errors that are far more difficult to correct because you're warned of them later than with traditional (read non OO) methods.

Marc