[Python-Dev] Re: Re: lists v. tuples (original) (raw)

Guido van Rossum guido@python.org
Wed, 16 Apr 2003 11:32:28 -0400

However, I'm slightly dubious about the x.sort(lt=f) vs x.sort(cmp=f) technique because it doesn't generalize terribly well.

If I want to write a function that takes a comparison function as an argument, and eventualy passes that function to sort, what do I do? Something like this? def myfun(foo, bar, lt=None, cmp=None): # ... x.sort(lt=lt, cmp=cmp) # ... and assume that sort will use None as its defaults also? Or must I write if lt==None: x.sort(cmp=cmp) else: x.sort(lt=lt) Either way it's inconvenient.

Given that (if we add this) the cmp argument will be deprecated, myfun() should take a 'lt' comparison only.

So I wonder if it might be better, as a way of allowing sort to take two different types of comparison functions, to distinguish between them by making them different types.

But Python doesn't do types that way.

--Guido van Rossum (home page: http://www.python.org/~guido/)