Luabind

If you are looking for a free and open source library to create bindings between C++ and Lua, then Luabind is definitely worth checking out. This powerful library is designed to help expose functions and classes written in C++ to Lua. With Luabind, you have the ability to define classes in Lua and let them derive from other Lua classes or even C++ classes. Additionally, Lua classes can easily override virtual functions from their C++ base classes.

It's important to note that Luabind is specifically written for Lua 5.x and will not work with Lua 4. The library is implemented using template meta programming, which means you won't need an extra preprocess pass to compile your project. This is done by the compiler, making it a breeze to use. Plus, you don't always have to worry about the exact signature of each function that you register. The library generates code depending on the compile-time type of the function.

One disadvantage of Luabind's approach is that the compilation time may increase for the file that does the registration. To avoid this issue, it's recommended that you register everything in the same CPP file. It's also important to note that Luabind is licensed and distributed under the terms of the Boost Software License (BSL1.0) and the MIT License, so you know you are working with a reliable and trustworthy piece of software.

All in all, Luabind is a great software option for anyone looking to create bindings between C++ and Lua. It has great functionality, with the added bonus of being free and open source.