Benchmark: running Regexp, Regexp D&P, Substring, each for at least 5 CPU seconds...
    Regexp:  6 wallclock secs ( 5.38 usr +  0.00 sys =  5.38 CPU) @ 173245.35/s (n=932060)
Regexp D&P:  6 wallclock secs ( 5.30 usr +  0.00 sys =  5.30 CPU) @ 200480.57/s (n=1062547)
 Substring:  7 wallclock secs ( 5.45 usr +  0.00 sys =  5.45 CPU) @ 1004355.05/s (n=5473735)