At the place of my work, I have a number of Perl scripts that required extensive debugging (final stage of development). As always, I have been using the handy 'perl -d' command to debug all of my scripts. And to set break points inside my code, I'd used to write '$DB::single = (break condition);'. However, in the end I'd always get tens of such statements that didn't make much sense to anyone who's not familiar with perl debugging mechanisms. My boss, in fact, was the first one to pointed me to the fact. This started me on thinking hard of how I could make it look clearer (without using those seamless 'DB::' variables...). In the end, I was determined enough to write a quick DEBUGGER module that would provide both the cleaner look and straightforward mechanism (or interface to) for controlling the Perl debugger. Here's the DEBUGGER module: 
package DEBUGGER;

use Exporter;
@ISA = qw(Exporter);

$::debug_level = 0; # default debug level

sub _check_debug_level {
    my ($debug_level_low, $debug_level_hi) = @_;
    $debug_level_hi ||= $::debug_level;

    return (($::debug_level >= $debug_level_low)
            && ($::debug_level <= $debug_level_hi));
}

# --- break($;$) ----
# set break point.
#
sub break($;$) {
    $DB::single = _check_debug_level(@_);
}
push @EXPORT, 'break';
#
# // break()
# -------------------

# --- break_if($;$$) ----
# set conditional break point.
# (could also be tied to specific
#  debugging levels)
#
sub break_if($;$$) {
  $DB::single = shift
    && (@_ && _check_debug_level(@_));
}
push @EXPORT, 'break_if';
#
# // break()
# -------------------

sub import {
  my ($pkg, %args) = @_;
  $::debug_level = $args{debug_level} if (exists $args{debug_level});

  __PACKAGE__->export_to_level(1);
}

[download]


and a test script: 
use strict;
use DEBUGGER (
              debug_level => 2,
              );

my $x = 2 * 2;

# will break here if debug level falls between
# 1 and 3 (inclusively).
break 1,3;
my $s = "foobar";

break 5;
print "will break here iff debug level is 5\n";

# break here if $x is less than 3
# and debug_level is set to 2
break_if $x < 5, 2;
print "exiting...\n";

[download]


Before using this module to debug my scripts, however, I'd like to hear a few words of wisdom from the Monastery community. I'd appreciate suggestions on what's missing and would be a nice thing to add (or, subtract for that matter). My hope is also that some of you might find it useful in your own debugging 'initiatives' ;-).

"There is no system but GNU, and Linux is one of its kernels." -- Confession of Faith

In reply to Perl debugging - a look at 'beta' mechanism by vladb

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