[Python-ideas] Predicate Sets

[Andrew Barnert]

On Jan 20, 2014, at 2:26, Devin Jeanpierre <jeanpierreda at gmail.com> wrote:

> There is not any kind of fundamental problem with the idea of a Python
> set-like object defined by Python predicates. Python sets aren't
> mathematical sets, and Python predicates aren't mathematical
> predicates. Things can be different from how they are described in
> mathematics, without being internally inconsistent, and without being
> useless.

I made the exact same point in the rest of the paragraph that you cut off, except I said that python functions aren't mathematical functions instead of saying predicates.

The original post was suggesting that Python should have predicateset because that's how mathematicians define sets. That is wrong--and, more importantly, irrelevant. Whether a predicateset class is useful or not has to do with its usefulness in writing and reading Python programs, and nothing else. Maybe I should have made the point about it being irrelevant first, and just mentioned the fact that it's wrong as a parenthetical comment. But I'm just too fond of the idea of being able to write a program that Captain Kirk or Zoe Heriot can use to blow up the computer after it takes over the world, which sadly Python does not yet have. (If I remember right, the computer Zoe did it to was programmed in Algol.)