// F# program that uses fractions.dll, which was written in C#
// Please read fractions.cs first and pay attention to details.

// uncomment following line if used in interactive console with .fsx extension
// #r "d:\\files\\fractions.dll";;  // EDIT PATH!

open System;  


// define a list of numbers that can contain integers and fractions

type number = Rat of fraction | Int of int;;

type nlist = Cons of number*nlist | Nil;;


// function that prints every element of an nlist:

let rec printnl = function
| Nil -> Console.WriteLine("");  // carriage return
| Cons(Int(n),t) -> Console.Write(string(n)+" ");
                    printnl t;
| Cons(Rat(r),t) -> Console.Write(r.ToString()+" "); printnl t;;

let half = fraction(1,2);
let quarter = new fraction(1,4);  // "new" is optional

let M = Cons(Int(2),Cons(Rat(half),Cons(Int(4),Cons(Rat(quarter),Nil))));

printnl M;

/////////////////////////////
// Compilation directions:
//   After installing Fsharp, 
//   add path to directory containing the compiler, fsc.exe,
//   to windows system environment variable Path.
//
//   Compile this program with
//
//   fsc numlist.fs -r fractions.dll
//
//   This will produce numlist.exe
//
// 
// Alternatively, rename this file with a .fsx suffix (Fsharp script), then
// uncomment #r directive above and 
// run this program in Fsharp interactive mode by typing
// #load "c:\\path..\\numlist.fsx";;