...Although it is possible to interact with the library directly in C (that is what the adg-demo program is doing), the canvas is expected to be used from higher level languages, much in the same way as what done in the GNOME stack.
Lua bindings based on LGI are already provided out of the box. The adg-lua project, downloadable from the "Files" section, provides Lua programs and demos that leverages these bindings.