Play with the created objects

Perl
Object Oriented
Object contents

Let's play with the created object.

1. Play with objects

First, let's create a $book object like this. Where it says to play around here, write various things and play.

use strict;
use warnings;

my $book = Book->new;

#
# Play around here.
#

package Book;
sub new {
    my $class = shift;
    my $self = {};
    return bless $self, $class;
}

2. Objects are data!

Let's make sure that the object is data .

$book->{title} = 'Good news';
$book->{author} = 'Takeshi';

You can see that you can set the value in the same way as a normal hash reference .

print $book->{title};

Then, the set contents will be output.

3. Objects are tied to a class!

Let's make sure that the object is tied to a class. To see the class association

ref

Use a function.

print ref $book;

Let's try.

Book

You can see that it is output. Yes, you can use the ref function to find out which class the object is associated with.

Perl ABC