Alex Martelli a écrit : > Bruno Desthuilliers <[EMAIL PROTECTED]> > wrote: > >> Alex Popescu a écrit : >>> Bruno Desthuilliers <[EMAIL PROTECTED]> wrote in >>> news:[EMAIL PROTECTED]: >> (snip) >>>> if hasattr(obj, '__call__'): >>>> # it's a callable >>>> >>>> but I don't find it so Pythonic to have to check for a __magic__ >>>> method. >>> It looks like Python devs have decided it is Pythonic, because it is >>> already in the PEP. >> I do know, and I disagree with this decision. >> >> FWIW, repr(obj) is mostly syntactic sugar for obj.__repr__(), >> getattr(obj, name) for obj.__getattr__(name), type(obj) for >> obj.__class__ etc... IOW, we do have a lot of builtin functions that >> mostly encapsulate calls to __magic__ methods, and I definitively don't >> understand why this specific one (=> callable(obj)) should disappear. I > > Maybe because it DOESN'T "encapsulate a call" to a magic method, but > rather the mere check for the presence of one?
Yes, true. But it doesn't make such a big difference IMHO : it's about decoupling API (the builtin funcs) from implementation (accessing | calling | checking for the presence of a given implementation attribute). >> usually have lot of respect for Guido's talent as a language designer >> (obviously since Python is still MFL), but I have to say I find this >> particular decision just plain stupid. Sorry. > > The mere check of whether an object possesses some important special > method is best accomplished through the abstract-base-classes machinery > (new in Python 3.0: see <http://www.python.org/dev/peps/pep-3119/>). At > this time there is no Callable ABC, but you're welcome to argue for it > on the python-3000 mailing list (please do check the archives and/or > check privately with the PEP owner first to avoid duplication). I'll have a look. Thanks for the pointers. -- http://mail.python.org/mailman/listinfo/python-list
