in reply to Combinatorics

#!/usr/bin/perl -w use strict; use Data::Dumper; sub unshift_many { my $scalar = shift; unshift @$_, $scalar for @_; @_; } sub combinations { my ( $array, $len, $start ) = @_; $start ||= 0; return unless $len > 0; return $len == 1 ? map [ $_ ], @{ $array }[ $start .. $#$array ] : map unshift_many( $array->[$_], combinations( $array, $len-1 +, $_+1 ) ), $start .. $#$array; } $Data::Dumper::Indent=0; print Dumper( [ combinations [ qw( 1 2 3 4 5 ) ], 3 ] ), "\n";

Makeshifts last the longest.