A while ago, I was writing a large script with a lot of data in a BEGIN block. I forget why.

But it was late in the morning and, of course, some part of the script wasn't working right, so I wrote a quick debugging routine using Data::Dumper that dumped some of the values in the BEGIN block.

When I came back to it the next day, it was entirely incomprehensible, so I boiled it down to the following code:

#!/usr/bin/perl
use warnings;
use strict;

use constant DEBUG => not undef;
use Data::Dumper;

BEGIN {
  my ($a, $b, $c) = (1, 2, 3);

  my $deb;
  if (DEBUG) {
    $deb = sub {
      print Data::Dumper->Dump([$a, $b, $c], [qw/a b c/]);
    };
  } else {
    $deb = sub {
      warn "Debugging not enabled!\n";
    }
  }

  sub debug { &$deb }
}
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The warn is there for when I removed the debugging information.

I would really like to know what I was thinking when I wrote this...