[Python-ideas] Json object-level serializer

[Antoine Pitrou]

Le jeudi 29 juillet 2010 à 15:42 +0200, Tarek Ziadé a écrit :
> On Thu, Jul 29, 2010 at 3:34 PM, Antoine Pitrou <solipsis at pitrou.net> wrote:
> > On Thu, 29 Jul 2010 15:25:20 +0200
> > Tarek Ziadé <ziade.tarek at gmail.com> wrote:
> >>
> >> That makes sense. OTHO, if we drop the idea of having a __magical__ method,
> >> we could have an collections' ABC instead, called JSONSerializable,
> >> with one method to override,
> >>
> >> This is more about declaring the interface rather than adding yet
> >> another __magic__ method
> >>
> >> That's a nice OOP pattern to have imho
> >
> > Python is supposed to be duck-typed. It would be strange to add a
> > couple of random exceptions to that general rule. Moreover, having to
> > *both* derive an existing class and implement the single method defined
> > on that class is one complication too many.
> 
> Not sure to follow here, since ABCs are about having an object
> supporting a series of methods no matter what are the parent classes.
> e.g. this is closer to the concept of "interfaces".
> 
> IOW you don't need to derive from a parent class, you just to need to provide
> a given set of methods, and ABC provides a ways to check that an
> object has that signature.

Ok, but then how does it avoid having a __magic__ method? You can't use
a normal name such as "to_json" because then an existing class with that
method could be wrongly inferred as implementing your new ABC, and break
existing code.

Besides, defining an ABC for a single, module-specific method sounds
rather overkill. This reminds of me of projects plagued by an overuse of
interfaces for every possible concept.

Regards

Antoine.