Discuss the principles of encapsulation and data hiding in Perl's OOP.

In Perl's object-oriented programming (OOP), encapsulation and data hiding are important principles that promote code organization, modularity, and data integrity. Let's explore each of these principles in detail:

1. Encapsulation:

* Encapsulation refers to the bundling of data (attributes) and methods (functions) within a class, and restricting direct access to the internal details of an object.
* Encapsulation helps to achieve information hiding, where the internal implementation details of an object are hidden from external entities, ensuring that they can only interact with the object through well-defined interfaces (methods).
* By encapsulating data and methods, the class acts as a protective container, ensuring that the object's state is accessed and modified only in a controlled manner.
* Encapsulation provides several benefits, such as code organization, abstraction, and improved maintainability, as changes to the internal implementation of a class do not affect the external code that uses the class.
* In Perl, encapsulation is typically achieved by declaring attributes as private (not directly accessible from outside the class) and providing public methods to manipulate and access the attribute values.
* Example:
```
perl`package MyClass;

# Private attribute
my $private_attribute;

# Public method to set the attribute value
sub set\_attribute {
my ($self, $value) = @_;
$private_attribute = $value;
}

# Public method to get the attribute value
sub get\_attribute {
my ($self) = @_;
return $private_attribute;
}`
```
2. Data Hiding:

* Data hiding is a specific aspect of encapsulation that focuses on restricting direct access to the internal data (attributes) of an object.
* In Perl, data hiding is achieved by declaring attributes as private using lexical variables (`my` keyword) within the class.
* By making attributes private, their values can only be accessed or modified through public methods provided by the class, ensuring proper encapsulation and control over the data.
* Data hiding provides an additional layer of security and integrity to the object's state, preventing unintended modifications or unauthorized access from external code.
* Example:


```
perl`package MyClass;

# Private attribute
my $private_attribute;

# Public method to set the attribute value
sub set\_attribute {
my ($self, $value) = @_;
$private_attribute = $value;
}

# Public method to get the attribute value
sub get\_attribute {
my ($self) = @_;
return $private_attribute;
}`
```
* In the example above, the `$private_attribute` is declared as a private variable within the class. It cannot be accessed directly from outside the class, ensuring data integrity and encapsulation.

By adhering to the principles of encapsulation and data hiding, Perl's OOP encourages modular and well-structured code. Encapsulation helps to achieve information hiding and abstraction, while data hiding ensures the proper access and modification of object data, promoting data integrity and security. These principles contribute to code maintainability, reusability, and the creation of robust and scalable applications.