#!/usr/lib/perl
use strict;
use warnings;

my @groups;
my $size;

while (<DATA>) {
    chomp;

    my ($type, $value) = split /\s*=\s*/, $_, 2;
    
    next if ! defined $value;
    
    if ($type eq 'fixed_size') {
        $size = $value;
        next;
    }
    
    push @groups, [split (/ /, $value), undef];
}

pickem ($size, [], @groups);


sub pickem {
    my ($needed, $givenList, @options) = @_;
    my $list = shift @options;
    
    for my $item (@$list) {
        if (! defined $item) {
            pickem ($needed, $givenList, @options);
            next;
        }
        
        if ($needed == 1) {
            print "@$givenList $item\n";
            next;
        }
        
        pickem ($needed - 1, [@$givenList, $item], @options);
    }
}


__DATA__
group_1 = A B C
group_2 = 1 2 3 4
group_3 = yellow blue green
group_4 = tiny small medium large gigantic
fixed_size = 2