Search⌘ K
Home
Courses
Mastering Modern Perl: Writing Efficient and Maintainable Code

Reflection

Explore the concept of reflection in Perl using Moose's Class::MOP and other Perl idioms to inspect and manipulate running programs. Understand how to verify module loading, package and class existence, check version numbers, functions, and methods, and work with symbol tables for effective object-oriented programming and code management.

We'll cover the following...

Overview

Reflection (or introspection) is the process of asking a program about itself as it runs. By treating code as data, we can manage code in the same way that we manage data. That sounds like a truism, but it’s an important insight into modern programming. It’s also a principle behind code generation.

Moose’s Class::MOPThe bundled Class::MOP library of Moose provides a meta-object protocol—a mechanism for creating and manipulating an object system by manipulating objects. simplifies many reflection tasks for object systems. Several other Perl idioms help us inspect and manipulate running programs.

Checking that a module has loaded

If we know the name of a module, we can check that Perl believes it has loaded that module by looking in the %INC hash. When Perl loads code with use or require, it stores an entry in %INC where the key is the file path of the module to load, and the value is the full path on disk to that module. In ...