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

How to use userdata

From this section onwards, we will transform the Destinations class from the previous chapter and register it to Lua as a type so that Lua code can create objects from it. Before we dive into the details, let’s make some high-level changes to show what we want at the project level.

Preparing the C++ type

In the previous chapter, we passed a name to the constructor for the Destinations class because we created its instances in C++ and needed to set a name to Lua for each instance.

In this chapter, we will export the C++ type to Lua. Lua will create the object and assign it a name. All changes will be in the Destinations class. The mechanism we implemented in the Lua executor to register C++ modules is flexible enough to support the registration of C++ types as well.

To reflect this change and difference, we will change the constructor and how the module name is provided. In Destinations.h, change the constructor, as follows:

class Destinations...