When should you prefer roles and composition, and when should you avoid it?

In Perl, choosing between roles and composition often depends on the specific requirements of your application, the complexity of the system, and the desired level of flexibility. Here’s when to prefer and avoid roles and composition:

When to Prefer Roles:

Dynamic Behavior: Use roles when you need to dynamically add behavior to objects at runtime.
Multiple Inheritance: When your classes need to share common functionality without a strict inheritance hierarchy.
Code Reusability: Roles promote reusability by allowing you to compose new classes with existing roles, minimizing code duplication.
Readable Design: Roles can make your design more understandable as they encapsulate specific behaviors that can be easily shared.

When to Avoid Roles:

Performance Concerns: Adding roles can introduce overhead; consider composition for performance-critical applications.
Simple Applications: In straightforward cases, traditional inheritance may suffice and be less complex.
Over-Engineering: If roles complicate the design unnecessarily, it's better to use simpler approaches.

When to Prefer Composition:

Explicit Relationships: Use composition when class relationships need to be clear and explicit.
Encapsulation: Composition enhances encapsulation by keeping a clear separation of concerns between components.
Easier Testing: Compositional designs often result in more testable code, as components can be tested independently.

When to Avoid Composition:

Complexity: For applications where the number of components is too high, leading to potential management overhead.
Interdependent Components: If components are highly dependent on one another, roles may provide better flexibility.

Example:


        # Example of roles and composition in Perl
        package Role::Logger {
            use Moose::Role;
            sub log {
                my ($self, $message) = @_;
                print "[$self->{name}] $message\n";
            }
        }

        package MyClass {
            use Moose;
            with 'Role::Logger';

            has 'name' => (is => 'ro', default => 'MyClass');

            sub do_something {
                my $self = shift;
                $self->log("Doing something.");
            }
        }

        my $obj = MyClass->new();
        $obj->do_something();

When should you prefer roles and composition, and when should you avoid it?

When to Prefer Roles:

When to Avoid Roles:

When to Prefer Composition:

When to Avoid Composition:

Example:

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When should you prefer roles and composition, and when should you avoid it?

When to Prefer Roles:

When to Avoid Roles:

When to Prefer Composition:

When to Avoid Composition:

Example:

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