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

Supporting different argument types

In the last chapter, we implemented our C++ function to call a Lua function as follows:

std::string call(const std::string &function,
                 const std::string &param);

Our goal in this step is to make it more general and we want the following instead:

LuaValue call(const std::string &function,
              const LuaValue &param);

In fact, go ahead and change this in LuaExecutor.h. To make it work, we will implement helper functions to push onto and pop from the Lua stack, with our LuaValue C++ type instead of std::string. Let us work on pushing onto the stack first.

Pushing onto the stack

In the previous call function, we pushed the param argument of the std::string type onto the Lua stack with the following:

lua_pushstring(L, param.c_str());

To...