True/False

Erik Max Francis max at alcyone.com
Tue Apr 22 23:17:39 CEST 2003


Ian Bicking wrote:

> I've been using True and False for a while now, and I put this at the
> top of my files:
> 
> True, False = 1==1, 0==1
> 
> But people seem concerned about this with Python 2.3.  I don't think
> they should be concerned, while I'm reassigning True and False, I'm
> not
> redefining them.

There was talk about instituting warnings for rebinding True and False
to any value, like is currently done for None:

Python 2.3a2 (#1, Feb 19 2003, 20:06:49) 
[GCC egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> None = 'asdf'
<stdin>:1: SyntaxWarning: assignment to None

If done, then a blanket statement like yours above would start
generating warnings eventually; they'd be harmless warnings, but they'd
be unnerving and annoying.

> import sys
> if sys.version_info < (2, 3):
>     True, False = 1==1, 0==1

This would be okay (although the untyped version of the True and False
builtins were introduced in 2.2, not 2.3).  The solution I've adopted
is:

	try:
	    True
	except NameError:
	    True, False = 1, 0

-- 
 Erik Max Francis / max at alcyone.com / http://www.alcyone.com/max/
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