[Freeswitch-users] how to run Lua commands in freeswitch?

i have created the file named "helloworld.lua" like this: session:answer(); session:streamFile("blah.wav"); session:hangup(); and it working correctly, **now i want to use lua command -not freeswitch command -in lua  for example run: op='+' if op == "+" then r = a + b elseif op == "-" then r = a - b elseif op == "*" then r = a*b elseif op == "/" then r = a/b else error("invalid operation") end but how can do that? thanks alot