The new Lua scripting API discussed in my previous post is making good progress!
I have written the full documentation. The goal of the Solarus engine is to be a generic Zelda-like 2D game engine, so it needs a powerful scripting API, as well as good documentation to make it usable.
This brand new Lua API allows to customize everything, including the menus and the head-up display. The documentation fully specifies every data type accessible from Lua with their methods and callbacks: map entities, menus, sprites, movements, savegame, etc.
If you are making a game with the Solarus engine, this Lua API reference will become your favorite website 
The API is still experimental, but most of the work is done. As it is getting more and more stable every day, I now keep the online documentation always up-to-date with the git branch solarus-1.0.0 of the engine.