Rosalind: character based phylogeny in Perl 6

chbp

use v6;
my @sample = «
    'cat dog elephant mouse rabbit rat'
    011101
    001101
    001100
»;
my $species = set my @species = @sample.shift.words; #get.words;
my @split = map {
    item set map *.key, grep *.value, hash @species Z=> .comb
}, @sample; #lines;

loop {
    for terminal-split() {
        my $ancestor = "({join ',', .list.sort})";
        note $species = set ($species (-) $_), $ancestor;
        say "({join ",", $species.list});" and exit if $species.elems == 3;
        for @split -> $split is rw {
            if $_ (<=) $split {
                $split = $split (-) $_;
                $split = set $split, $ancestor;
            }
        }
    }
}

sub terminal-split {
    gather for @split {
        take .item if .elems == 2;
        take item $species (-) $_ if .elems == $species.elems - 2;
    }
}