Tim Peters wrote: > ... > > [Anna] > >> BTW - I am *quite* happy with the proposal for "where:" syntax - I > >> think it handles the problems I have with lambda quite handily. > > [Steve Holden] > > Whereas I find it to be an excrescence, proving (I suppose) that one > > man's meat is another person's poison, or something. > > I've been waiting for someone to mention this, but looks like nobody > will, so I'm elected. Modern functional languages generally have two > forms of local-name definition, following common mathematical > conventions. "where" was discussed here. The other is "let/in", and > seems a more natural fit to Python's spelling of block structure: > > let: > suite > in: > suite
Ah. During that discussion, I did kind of suggest this (spelling it where...do) as an alternative to where (thinking I was clever). Only no one seemed to take notice, probably because I suggested something more poignant at the same time. Now I see why I liked the idea so much; it was exactly like let forms. > There's no restriction to expressions here. I suppose that, like the > body of a class, the `let` suite is executed starting with a > conceptually empty local namespace, and whatever the suite binds to a > local name becomes a temporary binding in the `in` suite (like > whatever a class body binds to local names becomes the initial value > of the class __dict__). So, e.g., > > i = i1 = 3 > let: > i1 = i+1 > from math import sqrt > in: > print i1, sqrt(i1) > print i1, > print sqrt(i1) > > would print > > 4 2 > 3 > > and then blow up with a NameError. > > LIke it or not, it doesn't seem as strained as trying to pile more > gimmicks on Python expressions. Indeed. -- CARL BANKS -- http://mail.python.org/mailman/listinfo/python-list
