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

Understanding name binding and dependent names

The term name binding refers to the process of finding the declaration of each name that is used within a template. There are two kinds of names used within a template: dependent names and non-dependent names. The former are names that depend on the type or value of a template parameter that can be a type, non-type, or template parameter. Names that don’t depend on template parameters are called non-dependent. The name lookup is performed differently for dependent and non-dependent names:

  • For dependent names, it is performed at the point of template instantiation.
  • For non-dependent names, it is performed at the point of the template definition.

We will first look at non-dependent names. As previously mentioned, name lookup happens at the point of the template definition. This is located immediately before the template definition. To understand how this works, let’s consider the following example: