Benchmark: timing 1000000 iterations of regex1, regex2... regex1: 9 wallclock secs ( 6.43 usr + 0.02 sys = 6.45 CPU) @ 155038.76/s (n=1000000) regex2: 2 wallclock secs ( 2.65 usr + 0.00 sys = 2.65 CPU) @ 377358.49/s (n=1000000)