On Tue, Jun 14, 2011 at 5:27 PM, Jan Kaliszewski <zuo@chopin.edu.pl> wrote:
Alex Light dixit (2011-06-14, 13:44):
frmglobals = func.__globals__.copy() func.__globals__.update(localArgs) ret= func(*args, **kwargs) func.__globals__.clear() func.__globals__.update(frmglobals)
Changing global state on each call seems to be both concurrency-and-recurrency-unsafe and inefficient.
well some of your safety concerns can be allayed, i hope, by replacing this snipet:
frmglobals = func.__globals__.copy() func.__globals__.update(localArgs) ret= func(*args, **kwargs) func.__globals__.clear() func.__globals__.update(frmglobals)
with this one:
with _modifyGlobals(func.__globals__, localArgs): ret = func(*args, **kwargs)
with _modifyGlobals defined as:
from contextlib import contextmanager
@contextmanager def _modifyGlobals(glbls, additions): frmglbls = glbls.copy() try: glbls.update(additions) yield finally: glbls.clear() glbls.update(frmglbls)
as for performance you are correct that it is more efficient to just use global variables. the dictionary updates add about 1 x 10**-4 (or, if the check for collisions with KWargs is removed, 5 x 10**-5) seconds to the run time of a function, at least on this computer. so not terribly significant just be sure to use sparingly also with the link you mentioned i could not seem to get it to work. Whenever i tried to use any built-in functions it would start throwing NameErrors. also that is only useful if you want to inject all global variables into the function. --Alex