[Python-ideas] Json object-level serializer (original) (raw)

Antoine Pitrou solipsis at pitrou.net
Thu Jul 29 15:49:42 CEST 2010

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.

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