Book Image

Integrate Lua with C++

By : Wenhuan Li
Book Image

Integrate Lua with C++

By: Wenhuan Li

Overview of this book

C++ is a popular choice in the developer community for building complex and large-scale performant applications and systems. Often a need arises to extend the system at runtime, without recompiling the whole C++ program. Using a scripting language like Lua can help achieve this goal efficiently. Integrate Lua to C++ is a comprehensive guide to integrating Lua to C++ and will enable you to achieve the goal of extending C++ programs at runtime. You’ll learn, in sequence, how to get and compile the Lua library, the Lua programming language, calling Lua code from C++, and calling C++ code from Lua. In each topic, you’ll practice with code examples, and learn the in-depth mechanisms for smooth working. Throughout the book, the latter examples build on the earlier ones while also acting as a standalone. You’ll learn to implement Lua executor and Lua binding generator, which you can use in your projects directly with further customizations. By the end of this book, you’ll have mastered integrating Lua into C++ and using Lua in your C++ project efficiently, gained the skills to extend your applications at runtime, and achieved dynamic and adaptable C++ development.
Table of Contents (18 chapters)
Free Chapter
1
Part 1 – Lua Basics
4
Part 2 – Calling Lua from C++
8
Part 3 – Calling C++ from Lua
12
Part 4 – Advanced Topics

Implementing a Lua executor

We will implement a reusable C++ Lua executor class step by step. Let us call it LuaExecutor. We will continue to improve this executor by adding new functions to it.

How to include the Lua library in C++ code

To work with the Lua library, you only need three header files:

  • lua.h for core functions. Everything here has a lua_ prefix.
  • lauxlib.h for the auxiliary library (auxlib). The auxiliary library provides more helper functions built on top of the core functions in lua.h. Everything here has a luaL_ prefix.
  • lualib.h for loading and building Lua libraries. For example, the luaL_openlibs function opens all standard libraries.

Lua is implemented in C and those three header files are C header files. To work with C++, Lua provides a convenient wrapper, lua.hpp, whose content is as follows:

extern "C" {
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
}

In your C++ code, lua...