use strict;
use warnings;
use Data::Dump qw/pp dd/;
use 5.12.0;

# https://perlmonks.org/?node_id=11121968

sub cross(&\@@) {
    my ( $code, $a_a, @b ) = @_;

    #warn pp $code, $a_a,\@b;

    map {
        $a = $_;
        map { $b=$_; &$code } @b;
    } @$a_a;
}


my @a = 1..3;
my @b = 4..6;
my @c = 7..9;


pp
  cross { $a.$b } @a,
  cross { $a.$b } @b,@c;