or download this
{ my %trd; sub trd { my $tr = $_[0]; $trd{$tr} ||= do { warn "compilin
+g tr$tr"; eval qq{sub {\$_[0]=~tr$tr}} }; } }
$t = $s = "hello, world\n"; &{trd("/a-z/n-za-m/")}($s); print $s; &{tr
+d("/a-z/A-Z/")}($t); print $t; &{trd("/a-z/n-za-m/")}($s); print $s;