[Python-Dev] PEP 443 - Single-dispatch generic functions (original) (raw)

Ronan Lamy ronan.lamy at gmail.com
Fri May 24 14:22:19 CEST 2013

2013/5/24 Ethan Furman <ethan at stoneleaf.us>

On 05/23/2013 02:02 PM, Ronan Lamy wrote:

2013/5/23 Łukasz Langa <lukasz at langa.pl <mailto:lukasz at langa.pl>>

On 23 maj 2013, at 20:13, Éric Araujo <merwok at netwok.org <mailto:_ _merwok at netwok.org>> wrote: > Question: what happens if two functions (say in two different modules) > are registered for the same type? Last one wins. Just like with assigning names in a scope, defining methods in a class or overriding them in a subclass. This is a serious annoyance, considering that there are several places where a large library can reasonably define the implementations (i.e. with the class, with the function, or in some utility module). Note that in contrast with the case of functions in a module or methods in a class, linting tools cannot be expected to detect a duplication between functions with different names defined in different modules. What would you suggest happen in this case?

Raise a ValueError, maybe? In that case, there needs to be a way to force the overriding when it is explicitly desired. One way would be to allow unregistering implementations: overriding is then done by unregistering the old implementation before defining the new one. This is a bit cumbersome, which IMHO is a good thing for an operation that is just as disruptive as monkey-patching a class or a module. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.python.org/pipermail/python-dev/attachments/20130524/9c932ad9/attachment.html>

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