NAME¶
Paranoid::Debug - Trace message support for paranoid programs
VERSION¶
$Id: Debug.pm,v 0.93 2010/06/03 18:58:30 acorliss Exp $
SYNOPSIS¶
use Paranoid::Debug;
PDEBUG = 1;
PDMAXINDENT = 40;
PDPREFIX = sub { scalar localtime };
pdebug("starting program", 1);
foo();
sub foo {
pdebug("entering foo()", 2);
pIn();
pdebug("someting happened!", 2);
pOut();
pdebug("leaving w/rv: $rv", 2):
}
perror("error msg");
# Deprecated
psetDebug(@ARGV);
DESCRIPTION¶
The purpose of this module is to provide a barely useful framework to produce
debugging output. With this module you can assign a level of detail to pdebug
statements, and they'll only be displayed when PDEBUG is set to that level or
higher. This allows you to have your program produce varying levels of
debugging output.
Using the
pIn and
pOut functions at the beginning and end of each
function will cause debugging output to be indented appropriately so you can
visually see the level of recursion.
NOTE: This module provides a function called
perror which
conflicts with a similar function provided by the
POSIX module. If you
use this module you should avoid using or importing POSIX's version of this
function.
NOTE: All modules within the Paranoid framework use this module. Their
debug levels range from 9 and up. You should use 1 - 8 for your own modules or
code.
SUBROUTINES/METHODS¶
PDEBUG¶
PDEBUG is an lvalue subroutine which is initially set to 0, but can be
set to any positive integer. The higher the number the higher the level of
pdebug statements are printed.
PDMAXINDENT¶
PDMAXINDENT is an lvalue subroutine which is initially set to 60, but can
be set to any integer. This controls the max indentation of the debug
messages. Obviously, it wouldn't help to indent a debug message by a hundred
columns on an eighty column terminal just because your stack depth gets that
deep.
PDPREFIX¶
PDPREFIX is also an lvalue subroutien and is set by default to a
subroutine that returns as a string the standard prefix for debug messages:
[PID - DLEVEL] Subroutine:
Assigning another subroutine reference to a subroutine can override this
behavior.
perror¶
perror("error msg");
This function prints the passed message to STDERR.
pdebug¶
pdebug("debug statement", 3);
This function is called with one mandatory argument (the string to be printed),
and an optional integer. This integer is compared against
PDEBUG and
the debug statement is printed if PDEBUG is equal to it or higher.
The return value is always the debug statement itself. This allows for a single
statement to produce debug output and set variables. For instance:
Paranoid::ERROR = pdebug("Something bad happened!", 3);
pIn¶
pIn();
This function causes all subsequent pdebug messages to be indented by one
additional space.
pOut¶
pOut();
This function causes all subsequent pdebug messages to be indented by one less
space.
psetDebug¶
psetDebug(@ARGV);
This function extracts all ^-v+$ arguments from the passed list and counts the
number of 'v's that result, and sets
PDEBUG to that count. You would
typically use this by passing @ARGV for command-line programs.
NOTE: This was a dumb idea of incredible proportions. As soons as it is
safe to do so I will kill this function and perform my penance before the gods
of bitrot. Consider this deprecated.
DEPENDENCIES¶
Paranoid
BUGS AND LIMITATIONS¶
perror (and by extension,
pdebug) will generate errors if STDERR
is closed elsewhere in the program.
There is also no upper limit on how much indentation will be used by the
program, so if you're using
pIn in deeply recursive call stacks you can
expect some overhead due some rather large strings being bandied about.
AUTHOR¶
(c) 2005 Arthur Corliss (corliss@digitalmages.com)
LICENSE AND COPYRIGHT¶
This software is licensed under the same terms as Perl, itself. Please see
http://dev.perl.org/licenses/ for more information.
(c) 2005, Arthur Corliss (corliss@digitalmages.com)