def test_string(prog: String, cname: String) = {
  val tks = tokenise(prog)
  //println(tks)
  val ast = Prog.parse_all(tks).head
  //println(ast)
  val code = fun_compile(ast)
  //println(code)
  os.write.over(os.pwd / (cname ++ ".ll"), code)
  //println(eval(ast))
}