use strict;
use warnings;
use Data::Dumper;

my $pt = { value => "D", next => undef }; 
my $pt2 = {value => "C", next => $pt};
$pt = {value => "B", next => $pt2};
my $L = { value => "A", next => $pt};

sub solution {
    my $list = shift;
    my $length = 0;
    while (1) {
	    return $length unless defined $list->{value}; # added for the case of an empty list
	    print $list->{value};
	    $length++;
	    return $length unless defined $list->{next};
	    $list = $list->{next};
    }
}
    
my $len = solution($L);
print "\n$len \n";

print Dumper $L;

##</code><code>##

ABCD
4
$VAR1 = {
          'next' => {
                      'next' => {
                                  'next' => {
                                              'next' => undef,
                                              'value' => 'D'
                                            },
                                  'value' => 'C'
                                },
                      'value' => 'B'
                    },
          'value' => 'A'
        };


##</code><code>##

my $L = {
	value => "A", next => {
		value => "B", next => {
			value => "C", next => {
				value => "D", next => undef,
			}
		}
	}
};


##</code><code>##

my $L;
for ( reverse qw / A B C D E F G/) {
	my $pt = { value => $_, next => $L };
	$L = $pt;
}

##</code><code>##

$ perl linked_list.pl
ABCDEFG
7
$VAR1 = {
          'next' => {
                      'next' => {
                                  'next' => {
                                              'next' => {
                                                          'next' => {
                                                                      'next' => {
                                                                                  'next' => undef,
                                                                                  'value' => 'G'
                                                                                },
                                                                      'value' => 'F'
                                                                    },
                                                          'value' => 'E'
                                                        },
                                              'value' => 'D'
                                            },
                                  'value' => 'C'
                                },
                      'value' => 'B'
                    },
          'value' => 'A'
        };