On Mon, Jun 3, 2013 at 3:04 AM, Rick Johnson
<[email protected]> wrote:
> * Woefully inadequate because: Switching on or off the debug
> messages is only valid in the current module that the
> function was imported. What if you want to kill all
> debugprint messages EVERYWHERE? Do you really want to edit
> "debug = BOOLEAN" in every source file OR do something
> stupid like import debugprint and edit the DEBUG constant
> OR even dumber, edit the debugprint source code? GAWD NO!
Easy fix to this one. Instead of copying and pasting debugprint into
everything, have it in a module and import it everywhere. Then the
debug flag will be common to them all.
Oh, and you probably want to add **kwargs to debugprint, because the
print function does a lot more than sys.stdout.write does:
>>> print(1,2,3,4,sep='#')
1#2#3#4
> * But even if you are willing to cope with all the "switch-
> on-and-off" nonsense, are you willing to have you code
> slowed by numerous calls to a dead function containing a
> comparison that will always be false?
Hmm. Could be costly. Hey, you know, Python has something for testing that.
>>> timeit.timeit('debugprint("asdf")','def debugprint(*args):\n\tif not DEBUG:
>>> return\n\tprint(*args)\nDEBUG=False',number=1000000)
0.5838018519113444
That's roughly half a second for a million calls to debugprint().
That's a 580ns cost per call. Rather than fiddle with the language,
I'd rather just take this cost. Oh, and there's another way, too: If
you make the DEBUG flag have effect only on startup, you could write
your module thus:
if DEBUG:
debugprint=print
else:
def debugprint(*args,**kwargs):
pass
So you can eliminate part of the cost there, if it matters to you. If
a half-microsecond cost is going to be significant to you, you
probably should be looking at improving other areas, maybe using
ctypes/cython, or possibly playing with the new preprocessor tricks
that have been being discussed recently. There's really no need to
change the language to solve one specific instance of this "problem".
ChrisA
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