[Python-3000] Generic function PEP won't make it in time

Phillip J. Eby pje at telecommunity.com
Mon Apr 23 19:54:53 CEST 2007

At 01:37 PM 4/23/2007 -0300, Leonardo Santagada wrote:
>i've thought that the overloading in GF was more for rules like (bar > 
>100) and not for diferent types. will both be suported or only the example 
>that you gave?

The idea is that it should be possible for third-party implementations to 
add support for more sophisticated rules.  The base system would support 
type annotations on arguments only -- and *maybe* interfaces.

This would be done by implementing the generic function implementation 
using generic functions -- something I've already done in 
PEAK-Rules.  Basically, the dispatch machinery is decoupled from the 
mechanism for specifying methods, and if you implement a new dispatcher 
(e.g. one supporting rules like "bar>100"), you simply also register 
methods with the overloading module's generic functions to support your new 
dispatcher.  That way, people can use your "rule" objects with @when, 
@around, @before, @after, etc., without having to learn anything but how to 
create and use other kinds of rules.

>ps: I didn't respond to python-3000 because I was afraid of disturbing 
>serious discussions over there.

This is as serious a discussion as any; if you thought of the question, 
chances are good that somebody else had this question also.  Thus, I'm 
cc:ing this back to the list, before any of them decide to ask me, too.  :)

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