use strict;

my $quote_ref  = {
  phrase   => "Foo",
  author   => "Bar",
  approved => 1,
};

set_phrase($quote_ref, "Bee");
print STDOUT get_phrase($quote_ref) . "\n";
print STDOUT get_author($quote_ref) . "\n";
print STDOUT (is_approved($quote_ref) ? "Is approved\n" : "Is not approved\n");

exit 0;

sub get_phrase {
  my $hash_ref = shift;
  return $hash_ref->{phrase};
}

sub set_phrase {
  my $hash_ref = shift;
  $hash_ref->{phrase} = shift;
}

sub get_author {
  my $hash_ref = shift;
  return $hash_ref->{author};
}

sub set_author {
  my $hash_ref = shift;
  $hash_ref->{author} = shift;
}

sub is_approved {
  my $hash_ref = shift;
  return $hash_ref->{approved};
}

##</code><code>##

package Quote;

use strict;

my $quote_ref = {
  phrase   => "Foo",
  author   => "Bar",
  approved => 1,
};

sub get_phrase {
  return $quote_ref->{phrase};
}

sub set_phrase {
  $quote_ref->{phrase} = shift;
}

sub get_author {
  return $quote_ref->{author};
}

sub set_author {
  $quote_ref->{author} = shift;
}

sub is_approved {
  return $quote_ref->{approved};
}

1;

##</code><code>##

use strict;
use Quote;

print STDOUT Quote::get_phrase(), "\n";
print STDOUT Quote::get_author(), "\n";
print STDOUT (Quote::is_approved() ? "Is approved" : "Is not approved"), "\n";

exit 0;

##</code><code>##

Foo
Bar
Is approved

##</code><code>##

package Quote;

use strict;

sub new {

  my $class = shift;
  my $self = {};
  return bless $self, $class;
}

sub set_phrase {
  my $self = shift;
  my $phrase = shift;
  $self->{phrase} = $phrase;
}

sub get_phrase {
  my $self = shift;
  return $self->{phrase};
}

sub set_author {
  my $self = shift;
  my $author = shift;
  $self->{author} = $author;
}

sub get_author {
  my $self = shift;
  return $self->{author};
}

sub is_approved {
  my $self = shift;
  @_ ? $self->{_approved} = shift : $self->{_approved};
}

1;

##</code><code>##

use strict;
use Quote;

my $phrase = "Baz";
my $author = "Foo";

my $quote = Quote->new();
$quote->set_phrase($phrase);
$quote->set_author($author);

print STDOUT $quote->get_phrase(), "\n";
print STDOUT $quote->get_author(), "\n";
print STDOUT ($quote->is_approved() ? "Is approved" : "Is not approved"), "\n";

exit 0;

##</code><code>##

Baz
Foo
Is not approved

##</code><code>##

sub new {
        my $class = shift;
        my $self = {};
        print STDOUT ref($self), "\n";
        bless $self, $class;
        print STDOUT "Object ", $self, " is of class ", ref($self), "\n";
        return $self;
}

##</code><code>##

HASH
Object Quote=HASH(0x804b514) is of class Quote
Baz
Foo
Is not approved

##</code><code>##

sub set_phrase {
        my $self = shift;
        print STDOUT "Object ", $self, " is of class ", ref($self), "\n";
        my $phrase = shift;
        $self->{phrase} = $phrase;
}

##</code><code>##

Object Quote=HASH(0x804b514) is of class Quote

##</code><code>##

use strict;
use Quote;

my $phrase = "Baz";
my $author = "Foo";

my $quote1 = Quote->new();
my $quote2 = Quote->new();

$quote1->set_phrase($phrase);
$quote1->set_author($author);
$quote2->set_phrase($phrase);
$quote2->set_author($author);

$quote2->set_phrase("Some other phrase");
$quote1->set_author("Some other author");

print STDOUT $quote1->get_author(), " wrote ", $quote1->get_phrase(), "\n";
print STDOUT $quote2->get_author(), " wrote ", $quote2->get_phrase(), "\n";

exit 0;

##</code><code>##

Some other author wrote Baz
Foo wrote Some other phrase

##</code><code>##

sub set_phrase {
        my $self = shift;
        my $phrase = shift;
        if (length($phrase) > 155) {
                $self->{invalid} = 1;

                $self->{invalid_message} = "Quote is more than 155 characters";
        }
        $self->{phrase} = $phrase;
}

sub set_author {
        my $self = shift;
        my $author = shift;
        unless ($author) {
                $self->{invalid} = 1;
                $self->{invalid_message} = "You must specify an author";
        }
        $self->{author} = $author;
}

sub is_valid {
        my $self = shift;
        return ! $self->{invalid};
}

sub get_invalid_message {
        my $self = shift;
        return $self->{invalid_message};
}

##</code><code>##

sub set_phrase {
        my $self = shift;
        my $phrase = shift;
        if (length($phrase) > 255) {
                $self->{invalid} = 1;
                $self->{invalid_message} = "Quote is more than 255 characters";
        }
        $self->{phrase} = $phrase;
}

sub set_author {
        my $self = shift;
        my $author = shift;
        unless ($author) {
                $author = "Anonymous";
        }
        $self->{author} = $author;
}

##</code><code>##

package Saver;

use strict;

sub save {
        my $self = shift;
        return;
}

package Saver::File;

use strict;
use IO::Handle;

@Saver::File::ISA = qw(Saver);

sub new {
        my $class = shift;
        my $file  = shift;
        my $self  = {
                file    => $file,
        };
        return bless $self, $class;
}

sub _open {
        my $self = shift;
        open (OUT, ">" . $self->{file}) or die ("Unable to open file: " . $self->{file});
        $self->{fh} = \*OUT;
}

sub save {
        my $self = shift;

        my $line = shift;
        unless ($self->{fh}) {
                &_open($self);
        }
        print {$self->{fh}} $line . "\n";
}

sub DESTROY {
        my $self = shift;
        print STDOUT "Closing file\n";
        &_close($self);
        return;
}

1;


##</code><code>##

use strict;
use Quote;
use Saver;

my $file   = "temp_file.txt";
my $phrase = "Baz";
my $author = "Foo";

my $saver  = Saver::File->new($file);
my $quote1 = Quote->new();
my $quote2 = Quote->new();

$quote1->set_phrase($phrase);
$quote1->set_author($author);
$quote2->set_phrase($phrase);
$quote2->set_author($author);

$quote2->set_phrase("Some other phrase");
$quote1->set_author("Some other author");

$saver->save($quote2->get_author() . " wrote " . $quote2->get_phrase());
$saver->save($quote1->get_author() . " wrote " . $quote1->get_phrase());

print STDOUT "Exiting\n";
exit 0;

##</code><code>##

Exiting
Closing file

##</code><code>##

sub serialize {
  my $self = shift;
  my $quote = shift;
  my $text = '';
  $text .= $quote->get_author();
  $text .= " wrote ";
  $text .= $quote->get_phrase();
  return $text;
}

##</code><code>##

sub save {
        my $self = shift;
        my $quote = shift;

        unless ($self->{fh}) {
                $self->_open();
        }
        print {$self->{fh}} $self->serialize($quote) . "\n";
}

##</code><code>##

$saver->save($quote2);
$saver->save($quote1);

##</code><code>##

package Saver::Database;

use strict;
use DBI;

@Saver::Database::ISA = qw(Saver);

our $sql = "INSERT INTO quotes VALUES (0, ?)";

sub new {
        my $class = shift;
        my $db    = shift;
        my $user  = shift;
        my $pass  = shift;
        my $self  = {
                db      => $db,
                user    => $user,
                pass    => $pass,
        };
        return bless $self, $class;
}

sub _open {
        my $self = shift;
        my $dbh = DBI->connect("DBI:mysql:" . $self->{db} . ";host=localhost", $self->{user}, $self->{pass}) or die ("Couldn't connect to database: " . $DBI::errstr);
        $self->{dbh} = $dbh;
}

sub _close {
        my $self = shift;
        $self->{dbh}->disconnect() or die ("Couldn't disconnect from database: " . $self->{dbh}->errstr);
}

sub save {
        my $self = shift;
        my $quote = shift;
        unless ($self->{dbh}) {
                &_open();
        }
        my $sth = $self->{dbh}->prepare($Saver::Database::sql);
        $sth->execute($self->serialize($quote));
        $sth->finish();
}

sub DESTROY {
        my $self = shift;
        &_close();
        return;
}

##</code><code>##

my $saver  = Saver::File->new($file);

##</code><code>##

my $saver  = Saver::Database->new($db, $user, $pass);

##</code><code>##

sub phrase {
  my $self = shift;
  @_ ? $self->{phrase} = shift : $self->{phrase};
}

##</code><code>##

$quote->Set(phrase=>$phrase,author=>$author);

##</code><code>##

eval {
  $object->method($foo)
}

if (@$) {
  ... handle error ...
}