Meetup1

intro.fsx

// Syntax (keine Klammern, Funktionsaufrufe)
// value binding
let firstname : string = "Roman"
open System.Reflection
open System.Windows.Forms
open System.Security.Cryptography

let age : int = 37

// type inference

// reassign not working
age = 38

// mutable
let mutable alter = 27

alter <- 27

// aber das wollen wir ja nicht :D

// funktionen
let add2 x =
  x + 2

// Aufruf
add2 40

let modulo3 x =
  x % 3

modulo3 (add2 42)

// piping
42
|> add2
|> modulo3
|> (fun x -> x * 5)

// function composition
let add2Modulo3 =
  add2 >> modulo3

42 |> add2Modulo3


// expressions

let modulo2Is0 x =
  if x % 2 = 0 then
    "ja"
  else
    "nein"

let add x y =
  x + y

// currying
let add2Curry =
  add 2

// Listen
let liste = [1..10]

liste
|> List.map (fun x -> x + 1)

let greater5 x =
  x > 5

liste
|> List.map (fun x -> x + 1)
|> List.filter greater5

liste
|> List.map (fun x -> x + 1)
|> List.filter (not << greater5)


// Record
type Account =
  {
    Owner : string
    Balance : decimal
  }

let account =
  {
    Owner = "Roman"
    Balance = 10M
  }

let account2 =
  { account with Owner = "Lena" }

account

let withOwner owner account =
  { account with Owner = owner }

let withBalance balance account =
  { account with Balance = balance }

account
|> withBalance 20M
|> withOwner "Lena"

// DU
type Wert =
  | Bube
  | Dame
  | König
  | Ass

type Karte =
  | Karo of Wert
  | Herz of Wert
  | Kreuz of Wert
  | Pik of Wert

let welcheKarte karte =
  match karte with
  | Herz wert -> sprintf "Herz %A" wert
  | Karo wert -> sprintf "Karo %A" wert
  | Kreuz wert -> sprintf "Kreuz %A" wert
  | Pik wert -> sprintf "Pik %A" wert

welcheKarte (Bube |> Karo)