Exceptional inheritance patterns (was Re: [Python-Dev] Python in Unicode context)

[Holger Krekel]

Aahz wrote:
> On Thu, Aug 05, 2004, Holger Krekel wrote:
> > Guido van Rossum wrote:
> >>
> >> (It will also break code that creates a class used as an exception
> >> that doesn't derive from Exception, but those should be shot. :-)
> > 
> > Then i guess that searching down into a recursive structure and just 
> > raising an "i found it" result object up doesn't count as a use case in
> > your book, right?   It can avoid boilerplate code like return-if-not-None 
> > checks and I have used it for e.g. finding patterns in an AST-Tree. 
> 
> In cases where I've done this, I've always inherited from Exception or a
> subclass.  Is there any reason not to?

Sure, i can probably wrap the result object into some class
which inherits from Exception.  My point is that I like to
regard try/except as a mechanism for "out-of-band" objects.
Guidos "should be shot" seems to indicate he sees try/except
only useful/applicable to exception-handling. 

    Holger

P.S.: thanks for changing the subject line, should have done that earlier.