[Python-Dev] Expression optimizations

[Dino Viehland]

And slightly unrelated, but just showing how bizarre floats are:

>>> x = 1e66666
>>> y = x/x
>>> cmp(y, y)
0
>>> cmp(x/x, x/x)
-1

Yeah object identity checks!

From: python-dev-bounces+dinov=microsoft.com at python.org [mailto:python-dev-bounces+dinov=microsoft.com at python.org] On Behalf Of Daniel Stutzbach
Sent: Tuesday, February 10, 2009 12:43 PM
To: cesare.dimauro at a-tono.com
Cc: Python-Dev
Subject: Re: [Python-Dev] Expression optimizations

On Tue, Feb 10, 2009 at 2:36 PM, Cesare Di Mauro <cesare.dimauro at a-tono.com> wrote:
OK, so I can make assumptions only for built-in types.

Yes, but even there you have to be careful of odd corner-cases, such as:

>>> nan = float('nan')
>>> nan < nan
False
>>> nan >= nan
False
--
Daniel Stutzbach, Ph.D.
President, Stutzbach Enterprises, LLC