training fsharp 1

training1.fsx

printfn "hello world"
open System.Runtime.InteropServices

let mutable name = "toto"
name <- "tata"

let display text =
  printfn "%s" text

let add a b =
  a + b

add 1 1

let addOne = add 1
let addTwo = add 2
let addTree = addOne >> addTwo

addTree 2

// comparaison

2 = 4
2 = 2
// types

type Hotel =
  { Name : string
    Stars : int }

let hotel1 = { Name="Paris Hotel" ; Stars = 3 }
let hotel2 = { Name="Ladef Hotel" ; Stars = 4 }
let hotel1bis = { Name="Paris Hotel" ; Stars = 3 }
hotel1 = hotel2
hotel1 = hotel1bis

match hotel1 with
| { Name="Paris Hotel" }  -> printfn "popo"
| { Name=n } when n.Contains "hotel" -> printfn "tutu" 
| _ -> printfn "toto"


let addStars n hotel =
  { hotel with Stars=hotel.Stars+n }

let hotel1Bigger = hotel1 |> addStars 2
let ``hotel1 bigger`` = addStars 2 hotel1

printfn "%b" (hotel1Bigger = hotel1)

// tuples

let t1 = (1, 2, "toto")
let t2 = (1, (true, 4), "toto")

let (a,b,c) = t1

match t1 with
| (1,_,_) -> printfn "perdu"
| (a,b,c) when a > 3 -> printfn "gagné"
| _ -> printfn "encore un coup"

let n = 5
match n with 
| _ when n % 2 = 0 -> printfn "even"
| _ -> printfn "odd" 

let (|Even|Odd|) n =
  if n % 2 = 0
  then Even
  else Odd

match 4 with
| Even -> printfn "pair"
| Odd -> printfn "impair"

let n2 = Some "toto"
let n3 : string option = None

match n2 with
| Some n -> printfn "name: %s" n
| None -> printfn "Unknown"

let (|MultipleOf|_|) n x =
  if n % x = 0
  then Some ()
  else None

//(|MultipleOf|_|) 2 3

let multipleOf n x = x % n = 0

let (|Fizz|Buzz|FizzBuzz|Other|) x =
  if multipleOf 15 x
  then FizzBuzz
  elif multipleOf 5 x
  then Buzz 
  elif multipleOf 3 x
  then Fizz
  else Other

let fizzBuzz x =
  match x with
  | Fizz -> printfn "fizz"
  | Buzz -> printfn "buzz"
  | FizzBuzz -> printfn "fizzbuzz"
  | Other -> printfn "%d" x

fizzBuzz 3


[1 .. 20] |> List.iter fizzBuzz


let (|Fizz|_|) x = if multipleOf 3 x then Some x else None
let (|Buzz|_|) x = if multipleOf 5 x then Some x else None

let fizzBuzz' = function
  | Fizz (Buzz _) -> printfn "fizzbuzz"
  | Fizz _ -> printfn "fizz"
  | Buzz _ -> printfn "buzz"
  | x -> printfn "%d" x
  

[1 .. 20] |> List.iter fizzBuzz'