Perl 6 quicksort demo expanded

main.p6

use v6;

# Empty list sorts to the empty list
multi quicksort([]) { () }

# Called on a scalar item (not a list of one item) return it as a list
multi quicksort($item) { $item, }
 
# Otherwise, extract first item as pivot...
multi quicksort([$pivot, *@rest]) {
    return $pivot, unless @rest.elems;
    
    # Partition	
    my $before := @rest.grep: {$^item before $pivot};
    my $after  := @rest.grep: {$^item !before $pivot};
 
    # Sort the partitions.
    flat quicksort($before), $pivot, quicksort($after)
}
 
put quicksort 7; # sort a single item
put quicksort <hill fall year tire over hose week>; # sort words
put quicksort flat ^10, ^10; # sort 0-9, 0-9
put quicksort quicksort ^10; # sort result of sort 0-9
put quicksort (^1000).pick(10); # sort 10 random values in range 0-999