[Python-Dev] Organization of ABC modules (original) (raw)

Jeffrey Yasskin jyasskin at gmail.com
Sat Jan 26 06:38:14 CET 2008

On Jan 25, 2008 9:31 PM, Nick Coghlan <ncoghlan at gmail.com> wrote:

Raymond Hettinger wrote: >> If you want ABCs to be more easily recognizable >> as such, perhaps we could use a naming convention, > > Essentially, that's all I was asking for. It doesn't > really matter to me whether numbers.py gets called > abcnumbers or abc.numbers. Either one would be an > improvement.

I think the module level is the wrong granularity to be thinking about this - look at a module like collections, which contains not only ABC's related to containers, but also some useful concrete containers like deque and namedtuple. Any naming convention would have to be at the class level. For example: class NumberABC(metaclass=ABCMeta): ... class ComplexABC(NumberABC): ... class RealABC(ComplexABC): ... class RationalABC(NumberABC): ... class IntegralABC(RationalABC): ... I think adopting such a convention (at least for the standard library) would actually be useful. Normally, finding isinstance() type checks in code bothers me severely as it usually indicates that duck-typing has been broken. On the other hand, if I find a check in code that does something like: if not isinstance(x, NumberABC): raise TypeError("Not a number!") it would clearly still be extensible, as I would know just from the naming convention that a third party can register their type with NumberABC to make it usable with this function. Without a naming convention, I would always have to go check the definition of the type in the isinstance() call to see if the code was legitimate.

That's a good point. Someone already convinced me to name the test for numbers.py, test_abstract_numbers.py, so renaming the module makes sense too, although I agree that collections, which contains some concrete classes, should keep its current name. If others agree, want to send a patch?

-- Namasté, Jeffrey Yasskin

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