[Python-Dev] Making None a keyword (original) (raw)

M.-A. Lemburg mal@lemburg.com
Fri, 26 Apr 2002 09:58:36 +0200

Guido van Rossum wrote:

I'd like to make None a keyword. This prevents dumb users from assigning to it and screwing themselves, and can cause a slight speedup because using None avoids two dict lookups. - Any objections?

+1 but only if you use the standard mechanism for this: warnings in 2.3, SyntaxError in 2.4.

- Can somebody help me implement this? I've got the parser changes ready, but not the compiler changes.

Believe it or not, Zope3 contains code that will break with this change: there are functions with a default argument of the form None=None as a speedup hack. I think this is an argument for the change. :-)

Zope3 is not the only software using these kind of hacks to work around the builtins lookups.

-- Marc-Andre Lemburg CEO eGenix.com Software GmbH

Company & Consulting: http://www.egenix.com/ Python Software: http://www.egenix.com/files/python/