FizzBuzzLucky

gistfile1.fs

type Result =
  | Text of string
  | Number of int
  override self.ToString() = match self with | Text s -> s | Number i -> i.ToString()
let (>>=) f1 f2 m = match f1 m with | Text _ as r -> r | Number i -> f2 i
let rule f s = function | i when f i -> Text s | i -> Number i
let fizz = rule (fun i -> i % 3 = 0) "fizz"
let buzz = rule (fun i -> i % 5 = 0) "buzz"
let fizzbuzz = rule (fun i -> i % 3 = 0 && i % 5 = 0) "fizzbuzz"
let lucky = rule (fun i -> i.ToString().Contains "3") "lucky"
let calculate = lucky >>= fizzbuzz >>= fizz >>= buzz >> stdout.WriteLine
seq {1..20} |> Seq.iter calculate