Steven D'Aprano wrote: > On Wed, 06 Jul 2005 10:00:02 -0400, Jp Calderone wrote: > > >>On Wed, 06 Jul 2005 09:45:56 -0400, Peter Hansen <[EMAIL PROTECTED]> wrote: >> >>>Tom Anderson wrote: >>> >>>>How about just getting rid of del? Removal from collections could be >>>>done with a method call, and i'm not convinced that deleting variables >>>>is something we really need to be able to do (most other languages >>>>manage without it). >>> >>>Arguing the case for del: how would I, in doing automated testing, >>>ensure that I've returned everything to a "clean" starting point in all >>>cases if I can't delete variables? Sometimes a global is the simplest >>>way to do something... how do I delete a global if not with "del"? >>> >> >>Unless you are actually relying on the global name not being defined, >>"someGlobal = None" would seem to do just fine. >> >>Relying on the global name not being defined seems like an edge case. > > > Er, there is a lot of difference between a name not existing and it being > set to None.
Yes, they are not currently the same thing. But what if assigning a name to None actually unbound it's name? And accessing an undefined name returned None instead of a NameError? Using an undefined name in most places will still generate some sort of an None type error. I think the biggest drawback to this second suggestion is that we would have to test for None in places where it would matter, but that's probably a good thing and enables checking if a variable exists without using a try-except. $ cat mymodule2.py # define some temporary names a, b, c, d, e, f = 1, 2, 3, 4, 5, 6 # do some work result = a+b+c+d*e**f # delete the temp variables a = b = c = d = e = f = None # possibly unbind names This would work if None unbound names. > It is bad enough that from module import * can over-write your variables > with the modules' variables, but for it to do so with DELETED variables is > unforgivable. Yes, I agree using None as an alternative to delete currently is unacceptable. Cheers, Ron -- http://mail.python.org/mailman/listinfo/python-list
