// The sports team program in F#, illustrating classes

open System

let rand = Random();;  // random number generator (from .Net API)

type team = 
  val total:int
  val mutable wins:int
  val mutable losses:int
  new(t) = {total=t; wins=0; losses=0;} // this is a record, not piece of code
  member this.win = this.wins <- this.wins+1
  member this.lose = this.losses <- this.losses+1
  member this.wp =    
    let games = float (this.wins+this.losses) in
       if (games=0.0) then 0.0 else (float this.wins)/games
  member this.play (t2:team) =   // the ()'s are necessary
    let r = rand.NextDouble() in
      if r<0.5 then 
        this.win;  t2.lose; 
        printfn "you suck";
      else 
        this.lose; t2.win; 
        printfn("you still suck");;

let jets = team(16);;
let giants = team(16);;
jets.win;;
jets.lose;;
Console.WriteLine(string (jets.wp));;
jets.play(giants);;

let winning = function    // note pattern matching and type hint
  | ({wins=w; losses=l}:team) -> w>l;;

Console.WriteLine(string (winning jets));;