$ perl  testRegexen.pl
Benchmark: running capture, noCapture, noParens, twoRegexen for at least 3 CPU seconds...
   capture:  4 wallclock secs ( 3.20 usr +  0.00 sys =  3.20 CPU) @ 141750.00/s (n=453600)
 noCapture:  3 wallclock secs ( 3.04 usr +  0.02 sys =  3.06 CPU) @ 279933.01/s (n=856595)
  noParens:  1 wallclock secs ( 3.34 usr +  0.00 sys =  3.34 CPU) @ 261686.53/s (n=874033)
twoRegexen:  5 wallclock secs ( 3.41 usr +  0.01 sys =  3.42 CPU) @ 540171.35/s (n=1847386)
               Rate    capture   noParens  noCapture twoRegexen
capture    141750/s         --       -46%       -49%       -74%
noParens   261687/s        85%         --        -7%       -52%
noCapture  279933/s        97%         7%         --       -48%
twoRegexen 540171/s       281%       106%        93%         --
$