Benchmark: timing 1000000 iterations of index, regex...
     index:  2 wallclock secs ( 1.30 usr +  0.00 sys =  1.30 CPU) @ 771010.02/s (n=1000000)
     regex:  2 wallclock secs ( 1.09 usr +  0.00 sys =  1.09 CPU) @ 913242.01/s (n=1000000)