Thomas Wouters <thomas <at> python.org> writes: > It may be 'common' for programmers to try and write this kind of code (accept either a string or an instance, a sequence or a single object, etc) but it's certainly not a common idiom -- idioms don't suck
As an example, lets take a look at re.sub: sub(pattern, repl, string[, count]) The documentation says that "repl can be a string or a function" and "If repl is a function, it is called for every non-overlapping occurrence of pattern. The function takes a single match object argument, and returns the replacement string." This is certainly an example where different actions are taken based on the type of the object. And as for this being bad style - well, if the standard library can't be used as a model of API design -- especially a module that has been refactored as many times as re -- then what can be? Certainly this ability can be abused to create obscure code, but in this particular case the usage seems reasonable and relatively straight forward; I would hate to categorically forbid all uses of APIs that take actions based on object type rather than strict OOP. (Admittedly this particular case could be done without 'callable', since you could test for string type, and assume callable otherwise. However, that's not always going to be the case.) -- Talin _______________________________________________ Python-3000 mailing list Python-3000@python.org http://mail.python.org/mailman/listinfo/python-3000 Unsubscribe: http://mail.python.org/mailman/options/python-3000/archive%40mail-archive.com
