#!/usr/local/bin/perl

use strict;
use warnings;

use Want 'howmany';

sub multi_iterator {
    my ($iterator)=@_;

    return sub{
        my $context=wantarray();

        return unless defined $context;
        return $iterator->() unless $context;
        return map { $iterator->() } 1 .. howmany();
    };
}

sub counter {
    my ($from, $to, $step)= @_;
    $step ||= 1;

    return sub {
        return if $from > $to;
        my $value=$from;
        $value +=$step;
        return $value;
    };
}

#main
my $counter=counter(1, 10, 3);
my $iterator= multi_iterator($counter);

my ($un, $deux)=$iterator->();
my $trois=$iterator->();

#should print 1, 4, 7
print "Hack-27 ",  $un, ",", $deux, ",", $trois, "\n";