Book Image

Template Metaprogramming with C++

By : Marius Bancila
Book Image

Template Metaprogramming with C++

By: Marius Bancila

Overview of this book

Learn how the metaprogramming technique enables you to create data structures and functions that allow computation to happen at compile time. With this book, you'll realize how templates help you avoid writing duplicate code and are key to creating generic libraries, such as the standard library or Boost, that can be used in a multitude of programs. The introductory chapters of this book will give you insights into the fundamentals of templates and metaprogramming. You'll then move on to practice writing complex templates and exploring advanced concepts such as template recursion, template argument deduction, forwarding references, type traits, and conditional compilation. Along the way, you'll learn how to write variadic templates and how to provide requirements to the template arguments with C++20 constraints and concepts. Finally, you'll apply your knowledge of C++ metaprogramming templates to implement various metaprogramming patterns and techniques. By the end of this book, you'll have learned how to write effective templates and implement metaprogramming in your everyday programming journey.
Table of Contents (16 chapters)
Part 1: Core Template Concepts
Part 2: Advanced Template Features
Part 3: Applied Templates
Appendix: Closing Notes


Mixins are small classes that are designed to add functionality to other classes. If you read about mixins, you will often find that the curiously recurring template pattern is used to implement mixins in C++. This is an incorrect statement. The CRTP helps achieve a similar goal to mixins, but they are different techniques. The point of mixins is that they are supposed to add functionality to classes without being a base class to them, which is the key to the CRTP pattern. Instead, mixins are supposed to inherit from the classes they add functionality to, which is the CRTP upside down.

Remember the earlier example with knights and mages that could move forth and back with the step_forth and step_back member functions? The knight and mage classes were derived from the movable_unit class template that added the functions advance and retreat, which enabled units to move several steps forth or back. The same example can be implemented using mixins in a reverse order. Here is...