my ($pat, $char) = $pattern =~ m/(.*)(.)$/;
my $char_up = $char;
my $char_down = $char;

++$char_up unless ($char =~ m/[9Z]/i);
--$char_down unless ($char =~ m/[0A]/i);

my $search = qr/$pat$char|$pat$char_up|$pat$char_down/;
print $search;