Benchmark: timing 10000 iterations of idiomatic, map...
idiomatic:  3 wallclock secs ( 3.25 usr +  0.01 sys =  3.26 CPU) @ 3067.48/s (n=10000)
       map:  6 wallclock secs ( 5.91 usr +  0.01 sys =  5.92 CPU) @ 1689.19/s (n=10000)