All subsets of a list in Perl 6

Question

I wonder (remembering that Perl 6 has everything you could wish), whether there are some built-in instruments that can help to produce all the non-empty subsets (order doesn't matter) of a list.

E.g., I have a list:

my @a = 1, 2, 3;

I need a function f so that f(@a) will produce:

((1), (2), (3), (1, 2), (1, 3), (2, 3), (1, 2, 3))

Answer 1

@a.combinations(1..*)

will return the Seq you're looking for. Note that without the argument, an empty list would be generated as first element.