Perl 객체? Python과 비교하며 감을 잡아보자.

#!/usr/bin/env perl
use strict;
use warnings;
 
package Person;
 
sub new {
    my ($class,$name,$height) = @_;
    my $self = { name=>$name, height=>$height };
    bless $self, $class;
    return $self;
}
 
sub sayGreeting {
    my $self = shift;
    print "Hello!  My name is $self->{name}. ";
    print "I am $self->{height} feet tall!\n";
}
 
# Person을 상속하는 Man 객체
package Man;
our @ISA = qw(Person);    # Person을 상속한다.
 
sub new {
    my $class = shift;
    my $self = $class->SUPER::new( shift, shift );  # 자식객체의 생성자를 호출한다.
    $self->{age} = shift || 0;                        # age 속성을 추가한다. 인자가 없으면 기본으로 0살
    bless $self, $class;
    return $self;
}
 
sub set_age {
    my ( $self, $age ) = @_;
    $self->{age} = $age;
    return $self->{age};
}
 
sub sayGreeting {
    my $self = shift;
    $self->SUPER::sayGreeting();
    print "I am $self->{age} years old.\n";
}
 
package main;
 
my $tom = new Man("Tom",3);
$tom->sayGreeting();
$tom->set_age(1);
$tom->sayGreeting();
 
my $bill = new Man("Bill", 1, 3);
$bill->sayGreeting();

Hello!  My name is Tom. I am 3 feet tall!
I am 0 years old.
Hello!  My name is Tom. I am 3 feet tall!
I am 1 years old.
Hello!  My name is Bill. I am 1 feet tall!
I am 3 years old.

Perl’s objectoriented
features are relatively basic and not compulsory. Perl takes a belt-and-braces approach to
object-oriented programming, espousing no particular object-oriented doctrine (of which there are
many), but permitting a broad range of different object-oriented styles. Despite this, and arguably
because of it, Perl is more powerful as an object-oriented language than it is often given credit for.
Many object-oriented languages take a much stricter line. Being strict is the entire point for
some languages. Java, for instance, requires that everything be an object, even the main application.
Other languages have very precise views about what kind of object model they support, how multiple
inheritance works, how public and private variables and methods are defined, how objects are
created, initialized, and destroyed, and so on. Perl’s disposition inherits much from languages like
Lisp, which combine a deliberately very simple syntax with the ability to extend it in almost any
direction. As such, Perl does not endorse any particular model of object-oriented programming,
which makes it both extremely flexible and highly disconcerting to programmers used to a different
object-oriented style.