Is there a consensus on how to check a polymorphic instance?

[Carlos Ribeiro]

On 23 Nov 2004 19:58:31 -0800, Mike Meng <meng.yan at gmail.com> wrote:
> > I come from a very conservative background in software development
> > and strong checks are deeply rooted in my mind.
> 
> So do I, Dan.
> 
> I just can't imagine a `wild'  object whose interface is valid can
> truely do the right things. While in fact, when I typing this word, I
> realize we can't ensure the internal protocol will be obeyed even when
> the object IS-A base class instance.
> 
> Maybe it's time to rethink.

I understand, and I found myself using isinstance more often that I
would like to admit. Being trained in OO Pascal & Delphi it comes as
no surprise...
 
> It seems to me the virtue of dynamic langauge is, if it looks like a
> cat, it's a cat.  But the problem is still there: how do you know what
> it looks like before you treat it as a cat? isinstance(), , as Steve
> state, is too rigid.

Time for adapt(), I think...

-- 
Carlos Ribeiro
Consultoria em Projetos
blog: http://rascunhosrotos.blogspot.com
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