'oregex' => sub {
                    $test_char = chr( int( rand 256 ) );
                    if ($test_char =~ /^[A..Z]$/o) {} else {}
                   },

##</code><code>##

comp: 51 wallclock secs (50.38 usr +  0.00 sys = 50.38 CPU)
exist: 50 wallclock secs (48.57 usr +  0.00 sys = 48.57 CPU)
oregex: 55 wallclock secs (54.11 usr +  0.00 sys = 54.11 CPU)
regex: 54 wallclock secs (54.10 usr +  0.00 sys = 54.10 CPU)