I'd do it something like this:

  use strict;

  my $n = shift @ARGV;
  my $try = [ $n ];
  while ($try) {
    print join(' ', @$try), "\n";
    $try = next_partition($try);
  }
  exit 0; # all done

  sub next_partition {
    my $current = shift;  # an arrayref of numbers in descending order

    # find the last entry greater than one
    my $i;
    for ($i = 0; $i < @$current; ++$i) {
      last if $current->[$i] == 1;
    }
    --$i;

    # if all ones, there is no next partition
    return undef if $i < 0;

    # we'll strip off all the ones, and one more
    my $count = @$current - $i;
    # and must generate the first partition of that count
    # subject to a top limit of what's to our left
    my $limit = --$current->[$i];

    # replace the ones
    splice @$current, $i + 1, $count - 1,
        # with the first paritition (limited) of the count
        ($limit) x int($count / $limit), grep $_, $count % $limit;
    $current;
  }
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