private int messageBox (LuaCallFrame callFrame, int nArguments) {
        LuaTable lt = (LuaTable)callFrame.get(0);
        Engine.message(lt);
        return 0;
    }
Distance object's fake GetValue or __call method

Called from Lua code: dist:GetValue("metres") or dist("ft"),
where 'dist' is double, converts the number to specified units
and returns as double.
main/src/main/java/cgeo/geocaching/wherigo/openwig/WherigoLib.java