sub roman-to-dec($x) { state %rtoa = M=>1000, D=>500, C=>100, L=>50, X=>10, V=>5, I=>1; $x.uc.split('').map({ %rtoa{$_} }).reduce: { $^a+$^b-$a%$b*2 } } my @testdata = ; for @testdata -> $r { say "$r: ", roman-to-dec($r); }