Re: debug statements

If you use a constant sub (declared with the constant pragma) then the code should get optimized away at compile time.

use constant DEBUG => 0;
## ...
print "DEBUG: JINKIES!\n" if DEBUG();
[download]

There's also an evil live comments module (specially formatted text in comments is printed as debugging output) that someone wrote but the name of which escapes me at the moment . . .

Update: Smart::Comments, that was it. Of course that gets the usual "source filters are teh debil" warnings.

Comment on Re: debug statements Download Code

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Re^2: debug statements by djp (Hermit) on Oct 04, 2006 at 03:43 UTC
Source filters are only evil if you invoke them, the beauty of smart comments is that normally they're just comments. Just leave 'use Smart::Comments' out of your code, then to invoke the smart comments (and the source filter), invoke your script via: `perl -MSmart::Comments myscript.pl` [download] or for finer control: `perl -MSmart::Comments='####' myscript.pl` [download] See Smart::Comments for details. This way you have zero overhead except when debugging. I'm surprised this simple technique isn't mentioned in the documentation.	[reply] [d/l] [select]
Re^2: debug statements by monarch (Priest) on Oct 04, 2006 at 15:29 UTC
I have to say I really like this; I've been using Perl for a while but hadn't thought about optimising debug statements away at compile time using this trick. Thanks!	[reply]
Re^3: debug statements by djp (Hermit) on Oct 05, 2006 at 23:45 UTC
Well it's not really optimizing debug statements away at compile time, it's optionally compiling them in at compile time. Same difference I suppose.	[reply]


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