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Thu, 14 Dec 2000 05:42:11 -0800 · http://mail.python.org/pipermail/python-dev/2000-December/011012.html

I would take a guess that the "if 0:" is optimized away *before* the
inspection for a "global" statement. But the compiler doesn't know how to
optimize away "if (0):", so the global statement remains.

Ah. Just checked. Look at compile.c::com_if_stmt(). There is a call to
"is_constant_false()" in there.

Heh. Looks like is_constant_false() could be made a bit smarter. But the
point is valid: you can make is_constant_false() as smart as you want, and
you'll still end up with "funny" global behavior.

Cheers,
-g

On Thu, Dec 14, 2000 at 02:19:08PM +0100, Fredrik Lundh wrote:
> here's a simple (but somewhat strange) test program:
> 
> def spam():
>     a = 1
>     if (0):
>         global a
>         print "global a"
>     a = 2
> 
> def egg():
>     b = 1
>     if 0:
>         global b
>         print "global b"
>     b = 2
> 
> egg()
> spam()
> 
> print a
> print b
> 
> if I run this under 1.5.2, I get:
> 
>     2
>     Traceback (innermost last):
>         File "<stdin>", line 19, in ?
>     NameError: b
> 
> </F>
> 
> 
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-- 
Greg Stein, http://www.lyra.org/

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[Python-Dev] fuzzy logic?