[Perl 6] Set algebra.

my $a = (1, 2, 3).Set;
my $b = (2, 4).Set;

# Union.
$a (|) $b ~~ (1, 2, 3, 4).Set or die "Wrong status";

# Intersection.
$a (&) $b ~~ (2).Set or die "Wrong status";

# Difference.
$a (-) $b ~~ (1, 3).Set or die "Wrong status";

# Symmetric difference.
$a (^) $b ~~ (1, 3, 4).Set or die "Wrong status";

my $c = (2, 3).Set;

# Superset.
$a (>=) $c or die "Wrong status";

# Strict superset.
$a (>) $c or die "Wrong status";

# Subset.
$c (<) $a or die "Wrong status";

# Strict subset.
$c (<=) $a or die "Wrong status";