Benchmark: timing 2500 iterations of grepGen, mapGen, smartGen...
   grepGen: 23 wallclock secs (22.51 usr +  0.00 sys = 22.51 CPU) @ 111.06/s (n=2500)
    mapGen: 11 wallclock secs (11.42 usr +  0.00 sys = 11.42 CPU) @ 218.93/s (n=2500)
  smartGen:  1 wallclock secs ( 1.05 usr +  0.00 sys =  1.05 CPU) @ 2392.34/s (n=2500)