#!perl

use strict;
use warnings;

my $string  = "A Man, A Plan, A Canal -- Panama!";
my $letters = lc $string;

$letters =~ s/\W//g;

printf qq/"%s" %s a palindrome.\n/,
    $string, $letters eq reverse($letters) ? "is" : "isn't";

__END__

"A Man, A Plan, A Canal -- Panama!" is a palindrome.