Find and show all cycles of a permutation

find-all-cycles.pl

use v6;

sub MAIN(*@p) {
    die "Arguments need to be integers"
        unless all(@p) ~~ /^ \d+ $/;
    die "Arguments need to be 1..N in some order"
        unless sort(@p) ~~ [1..@p];

    say "($_)" for sort *.[0], gather for @p -> $e {
        next if (state %handled).exists($e);
        my @cycle = @p[$e - 1], { @p[$_ - 1] } ... $e;
        @cycle .= rotate(first { @cycle[$_] == @cycle.min }, ^@cycle);
        take [@cycle];
        ++«%handled{@cycle};
    }
}

I believe line 5 is incorrect (it merely checks if all of the grep results have true values, which is not the intent there). Perhaps:

    unless @p == grep /^ \d+ $/, @p;

Or even:

    unless @p == @p.grep: /^ \d+ $/;

Which makes it more clear that you're asking if the count of @p is the same as the count of the matching subset of @p.

Thanks, fixed!