To follow this chapter and this book, you will require the following:

• A working C++ compiler, preferably the GNU C++ Compiler or Clang/LLVM
• A build automation tool, preferably Make
• The code editor of your choice
• The Lua source code
• The source code for this chapter: https://github.com/PacktPublishing/Integrate-Lua-with-CPP/tree/main/Chapter01

You do not need prior Lua programming knowledge to understand this chapter. If you have any doubts relating to the Lua code examples in this chapter, that is fine; you can read it as C++ code, although there are syntax differences. You will learn Lua as you progress through this book. While it would be beneficial, you do not need to be a Lua expert if your focus is only on the C++ side.

We decided to use open-source compilers and build tools to work with the code examples in this book because they are readily available to everyone and are also the tools of choice in most large-scale projects...

There are many ways to access the Lua language. If you are using Linux, you can install Lua for development with the distribution’s package manager. For Windows, you can also find prebuilt binaries. However, since our goal is to integrate Lua into your C++ project, instead of using it as a standalone interpreter, it’s best to build from the source code yourself. When studying Lua, this will help you learn more about Lua. For example, in a modern code editor, Visual Studio Code included, you can easily check the declaration and implementation of Lua library functions.

In this section, we will focus on compiling Lua from its source code. Unarchive the downloaded Lua source code archive. Most compression tools support this, and the Lua download site also gives instructions. When you have done this, you will see a simple folder structure:

lua-5.4.6 % ls
Makefile README doc src

We will learn what the preceding code block does in the next...

Building your C++ project with the Lua library has the benefit of not having to include the 100+ Lua source files in your project and your source control system. However, it has some disadvantages as well. For example, if your project needs to support multiple platforms, you will need to maintain multiple pre-compiled libraries. In such a case, building from the Lua source code might be easier.

Creating a project to work with the Lua library

In the previous section, we built the Lua library from the source code. Now, let’s extract it to use within our project.

Remember the Makefile in the root of the source code folder? Open it and you will find the two lines shown here:

TO_INC= lua.h luaconf.h lualib.h lauxlib.h lua.hpp
TO_LIB= liblua.a

These are the header files and the static library you need.

Create a folder for your project. Within it, create an empty source file named main.cpp, an empty Makefile, and two empty...

Building your C++ project with the Lua source code has the benefit that it is always compiled as part of your project, and there is no possibility of any surprises arising from compiler incompatibilities.

The major difference from linking with a pre-compiled Lua library is that we will now compile the Lua library from its source code first. It is also better to use the source code package without modifying it or copying only a few selected files into a new folder hierarchy. This will help in the future if you need to use a newer Lua version. In such a case, all you will need to do is to replace the Lua source code folder with the new version.

Creating a project to work with the Lua source code

To create a project using the Lua source code, we need to go back to the Lua source code package:

lua-5.4.6 % ls
Makefile README doc src

You will need the src subfolder.

Create a folder for a new project. Within it, create an empty...

To execute a Lua script, you can choose to use either the Lua library or the Lua source code. For production projects, I personally recommend using the source code. For learning purposes, either way is fine. We will use Lua source code in the rest of this book.

Can you notice this?

Even if you choose to use the Lua source code, in the Makefile, you are first building the Lua source code into the Lua library and then make your project link to the library. Compared to using the Lua library directly, using the Lua source code is just doing one more step in your project. You can focus more on the similarities rather than the differences.

Now, let’s look at a more general project structure.

Creating a project

As said, there will be more complex projects in the following chapters. For now, we will explore a more general project structure. We will build and link to Lua in a shared location instead of making a copy for each project.

The...

If you do not have access to a native POSIX system, there are many other toolchain options. Here we have given two examples. Because your development platform may be different and OS updates and situations change, these only serve as some ideas. You can always research online and experiment to get a comfortable setup for yourself.

Using Visual Studio or Xcode

The Lua source code is written in C and does not need other dependencies. You can copy the src folder from the Lua source code package into Visual Studio or Xcode, either into your project directly or by configuring it as a Lua project that your main project depends on. Tweak the project settings as you need. This is quite doable.

Whatever IDE you choose to use, remember to check its license to see whether you can use the IDE for your purpose.

Using Cygwin

If you use Windows, you can get Cygwin for a POSIX experience:

1. Download the Cygwin installer from https://sourceware.org/cygwin...

In this chapter, we have learned how to compile the Lua source code, how to link to the Lua library, and how to include the Lua source code directly in your project. Finally, we executed a Lua script from C++ code. By following these steps yourself, you should be comfortable and confident in including Lua in your C++ projects and prepared for more complex work.

In the next chapter, we will learn the basics of the Lua programming language. If you are already familiar with the Lua programming language, feel free to skip Chapter 2, Lua Fundamentals. We will come back to the communications between Lua and C++ in Chapter 3, How to Call Lua from C++.