Lua interpreter embedded into an Excel XLL
LuaXLL is a lightweight Lua interpreter built into a Excel XLL. The XLL has extensions built into it which allow new Excel functions to be defined in a Lua script and exposed to the main application with the XLL marshalling data across the environments. Its primary use is for rapid modelling and development. And it could also serve as an interface to more advanced models built in C. It has built-in support for ODBC databases (via LuaSQL) and some generic modeling functions (added as I need them). The entire XLL is currently less than 600KB.