[Python-3000] Adaptation vs. Generic Functions

[Phillip J. Eby]

At 07:37 AM 4/7/2006, Jim Jewett wrote:
>On 4/7/06, Phillip J. Eby <pje at telecommunity.com> wrote:
> > Guido wrote:
> > >         mros = tuple(t.__mro__ for t in types)
> > >         n = len(mros)
> > >         candidates = [sig for sig in self.registry
> > >                       if len(sig) == n and
> > >                          all(t in mro for t, mro in zip(sig, mros))]
> >
> > I believe this can be simplified to:
> >      n = len(types)
> >      candidates = [sig for sig in self.registry
> >                    if len(sig) == n and
> >                       all(issubclass(s,t) for s,t in zip(sig, types))]
>
>Am I going nuts, or should that issubclass test be reversed?

No, you're right, I goofed.  To me, the "signature" was what the 
function was *called* with, so it seemed to read correctly to 
me.  i.e., I read it as "the calling signature item is a subclass of 
the target method's type"... which is the right idea, but the wrong 
variables.  :)