First, swig does support Lua ! (Swig and Lua
Since I really want the lua language to be supported by either Crystal Space and CEL, I think I can do it or at least, help doing it but because I know very few about Crystal Space and Jam(files) which are used to compile at least CEL, I think I would need some help.
I have nothing against Python which is a great language but there is no way to have restricted environments to execute untrusted code. Maybe it is possible with PyPy but ... I prefer a lightweight language like lua anyways.
So if someone could help me to start ... I tried directly with CEL but I think I will need to create bindings for CS first which is from my point of view far more complicated.