Book Image

Template Metaprogramming with C++

By : Marius Bancila
5 (1)
Book Image

Template Metaprogramming with C++

5 (1)
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)
1
Part 1: Core Template Concepts
5
Part 2: Advanced Template Features
9
Part 3: Applied Templates
Appendix: Closing Notes

Typelists

A type list (also spelled typelist) is a compile-time construct that enables us to manage a sequence of types. A typelist is somehow similar to a tuple but does not store any data. A typelist only carries type information and is used exclusively at compile-time for implementing different metaprogramming algorithms, type switches, or design patterns such as Abstract Factory or Visitor.

Important Note

Although both the type list and typelist spellings are in use, most of the time you will find the term typelist in C++ books and articles. Therefore, this will be the form we will use in this book.

Typelists were popularized by Andrei Alexandrescu in his book, Modern C++ Design, published a decade before the release of C++11 (and variadic templates). Alexandrescu defined a typelist as follows:

template <class T, class U>
struct Typelist
{
  typedef T Head;
  typedef U Tail;
};

In his implementation, a typelist is composed of a head—...