Those are permutations, not combinations. Order doesn't matter for combinations.

Algorithm::Loops has a function called NextPermute which iterates permutations. Taken almost verbatim from the documentation:

use Algorithm::Loops qw( NextPermute );

my @list = sort qw( a b c );
do {
   print(join(', ', @list), "\n");
} while (NextPermute(@list));
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