ok 1 - mca
       is mutating
       does not offend Perl::Critic
ok 2 - choroba
       is NOT mutating
       offends Perl::Critic
           Expression form of "grep" at line 6, column 5. See page 169 of PBP.
           Expression form of "map" at line 6, column 20. See page 169 of PBP.
ok 3 - tux
       is NOT mutating
       does not offend Perl::Critic
ok 4 - eplam
       is mutating
       does not offend Perl::Critic
           Rate   eplam choroba     mca     tux
eplam   41701/s      --     -2%    -40%    -54%
choroba 42626/s      2%      --    -39%    -53%
mca     69930/s     68%     64%      --    -23%
tux     91241/s    119%    114%     30%      --
1..4