[Python-Dev] PEP 443 - Single-dispatch generic functions

[Antoine Pitrou]

On Thu, 23 May 2013 12:12:26 +1000
Nick Coghlan <ncoghlan at gmail.com> wrote:
> On Thu, May 23, 2013 at 10:14 AM, Glenn Linderman <v+python at g.nevcal.com> wrote:
> > Yet about half of the operator overloads would be incomplete if there were
> > not corresponding __r*__ methods (__radd__, __rsub__, etc.) because the
> > second parameter is as key to the dispatch as the first.
> >
> > While unary operators, and one argument functions would be fully covered by
> > single dispatch, it is clear that single dispatch doesn't cover a large
> > collection of useful cases for operator overloading.
> 
> The binary operators can be more accurately said to use a complicated
> single-dispatch dance rather than supporting native dual-dispatch.

Not one based on the type of a single argument, though. I guess you can
also reduce every function of several arguments to a function accepting
a single tuple of several items, but that doesn't sound very
interesting.

Regards

Antoine.