Benchmark: timing 100000 iterations of chop, math, regex, substr...
      chop:  6 wallclock secs ( 4.92 usr +  0.03 sys = 4.95 CPU) @ 20202.02/s (n=100000)
      math:  2 wallclock secs ( 1.07 usr +  0.02 sys = 1.09 CPU) @ 91743.12/s (n=100000)
     regex: 25 wallclock secs (17.40 usr +  0.32 sys = 17.72 CPU) @ 5643.34/s (n=100000)
    substr:  2 wallclock secs ( 1.99 usr +  0.03 sys = 2.02 CPU) @ 49504.95/s (n=100000)