use strict;
use warnings;

sub make_tr {
        my $from=quotemeta(shift);
        my $to  =quotemeta(shift);
        (my $opts=shift || "")=~tr/cdsCDS/cdscds/d;
        my $tr=eval "sub { (defined \$_[0] ? \$_[0] : \$_)=~tr/$from/$to/$opts}";
        die "$@" if $@;
        return $tr;
}
my $tr=make_tr('A-Z','a-z');
my $x="YaBaDaBaDo";
$tr->($x);
print $x,"\n";
$_="FOO";
$tr->();
print;
__END__
yabadabado
foo