use 5.010;
use strict;
use warnings;
use constant DEBUG => 1;
no  if DEBUG, warnings => 'uninitialized';

my $x = 23;
my $y;

say "With DEBUG = ", DEBUG;

debug("x='$x' y='$y'") if DEBUG;

if (DEBUG)
{
    sub debug { say shift; }
}

##</code><code>##

22:41 >perl 1758_SoPW.pl
With DEBUG = 0

22:41 >perl 1758_SoPW.pl
With DEBUG = 1
x='23' y=''

22:41 >