#!/usr/bin/perl

#
# example.pl
#

use strict;
use warnings;


use Algorithm::Iters qw( NestedIters );


sub returns_an_iter1 {
   my $i = 0;
   sub { $i == 3 ? undef : ++$i }
}

sub returns_an_iter2 {
   my @data = ('y', 'n');
   sub { pop @data }
}

sub returns_an_iter3 {
   my $i = 0;
   sub { $i == 4 ? undef : ++$i * 7 }
}

sub print_values {
   local $, = ", ";
   local $\ = "\n";
   print @_;
}

NestedIters(
   [
      \&returns_an_iter1,
      \&returns_an_iter2,
      \&returns_an_iter3,
   ],
   \&print_values
);

# Also works
# ==========
# 
# print("\n");
# 
# NestedIters(
#    [
#       \&returns_an_iter1,
#       sub { [ 'y', 'n' ] },
#       \&returns_an_iter3,
#    ],
#    \&print_values
# );
# 
# print("\n");
# 
# NestedIters(
#    [
#       \&returns_an_iter1,
#       [ 'y', 'n' ],
#       \&returns_an_iter3,
#    ],
#    \&print_values
# );