"John Machin" <[EMAIL PROTECTED]> wrote: >> > if isinstance(.... >> > action_for_type1(... >> > # big snip >> > elif isinstance(... >> > action_typeN( ... >> > # no else statement >> >> Ouch.. someone must have skipped his/her OO class... > > Quite possibly :-) but that's not the problem here. > > The method in question might be called say emit_generic(self, > any_type_of obj) and so one bunch of isinstance calls is actually > needed, but not two bunches. So: lose the decorator and add an else and > a raise at the end. > > There is a secondary problem: annoying the crap out of callers who > often know what type they have and want an emit_real which would take > an int, a long, or a float and an emit_strg and ... (yes, almost all > the possible types are that simple) which wouldn't go through even one > chain of isinstance calls. >
I think the point that was being made was that the method's body should be something like: actions[type(arg)](...) which not only avoids all of the isinstance calls but also the else and the raise at the end. -- http://mail.python.org/mailman/listinfo/python-list
