[pyc] Re: Supporting constants for python.
- From: stelios xanthakis <sxanth@xxxxxxxxxxxx>
- To: pyc@xxxxxxxxxxxxx
- Date: Tue, 12 Jul 2005 15:58:16 +0300
Ikkei Shimomura wrote:
Hi, I also had interested in the topic,
that optimize python script on source/ast/bytecode layer.
As a part of meta-programming.
Recentlly, I've posted a recipe, which similar concept. (I found pyc already
does it and more)
upper-letters name variables as constants at compile time.
http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/435694
Good idea.
What we basically need is a dictionary 'D' available at
optimizer.visitName, where we will say:
if node.name in D:
make_const (...)
The question is how do get this dictionary.
One way, like in the recipe, is to use an external file for
this, and invoke pyc:
pyc --consts-file=define_constants.py test_constants.py
In this case i think it's better to use the "__all__ convention"
instead of "upper-letters", so that the code will still work
without pyc by writing:
from define_constants import *
The only disadvantage is that we will have dependancies:
if define_constants is modified, test_constants should be
recompiled. But that should be ok for people that use pyc.
define_constants should be:
#-------------------
import math
__all__ = ['PI', 'DEBUG']
PI=math.atan (1)*4.0
DEBUG=1
#--------------------
if anybody's using None as an argument,
they are looking for trouble anyway and the sooner they find it, the better?
Can you show any situations has the problem ? is it foo(None) ?
Or ssign value into 'None' is SyntaxError, now. is not that such thing ?
wrong comment:)
that was for the case:
def foo(None, x):
print None
which should be forbidden anyway.
Stelios
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