component call_a_function
  export Executable
  (* Declaring test functions that allow the various ways to call functions in Fortress to be demonstrated. *)
  addition(i:ZZ32, j:ZZ32): ZZ32 = i+j
  addition(i:ZZ32): ZZ32 = i+1

  (* Strings are concatenated by using a space as an infix operator. *)
  addition(i:String, j:String): String = i j

  printAString(s:String): () = println(s)

  (* Functions can be passed to other functions as arguments. When passing a function as an argument, the argument's type should be
  represented as follows: "typeOfArgument(s)->returnType," which, in this case, is "String->()." You could also technically use the
  "Any" type, but that isn't type-safe. *)
  printAString(s:String, f:String->()) = f(s)

  (* Defined functions can then be called as follows. *)
  var x:ZZ32 = addition(1, 2)
  var str:String = addition("This is ", "another string.")

  run() = do
    (* You can call built-in functions the same way that you call functions that you define. *)
    println("x at start: " x)

    x := addition(x, 2)

    println("x at middle: " x)

    printAString("This " "is " "a " "string.")
    printAString(str)
    printAString("\nThis is a string that is being printed by a function of the same name \nthat takes a function as an argument.\n",
      printAString)

    x := addition(4)

    println("x at end: " x)
  end
end