Benchmark: timing 1000000 iterations of String::Aprox, String::Similarity, Chainsaw... String::Aprox: 5 wallclock secs ( 3.70 usr + 0.02 sys = 3.72 CPU) @ 268889.49/s (n=1000000) String::Similarity: 7 wallclock secs ( 7.38 usr + 0.00 sys = 7.38 CPU) @ 135593 .22/s (n=1000000) Chainsaw: 15 wallclock secs (14.16 usr + 0.02 sys = 14.17 CPU) @ 70566.65/ s (n=1000000)