F#: 프로그래밍의 즐거움

// F#
let intList = [1; 2; 3]
let charArray = [|'a'; 'b'|]
let two = 2

let add sequence intValue =
    let length = Seq.length sequence // F#의 Seq는 IEnumerable
    length + intValue

let answer = add intList two // 5
let answer2 = add charArray two // 4

// Dotty(Scala 3)
val intList = List(1, 2, 3)
val charArray = Array('a', 'b')
val two = 2
def add[A](sequence: Seq[A], intValue: Int) = // Scala의 Seq는 모든 Collection의 인터페이스
    val length = sequence.length
    length + intValue

val answer = add(intList, two) // 5
val answer2 = add(charArray, two) // 4

// F#, 카운터 예제
// https://github.com/fable-compiler/fable2-samples/blob/master/minimal/src/App.fs
module App

(**
 The famous Increment/Decrement ported from Elm.
 You can find more info about Elmish architecture and samples at https://elmish.github.io/
*)

open Elmish
open Elmish.React
open Fable.React
open Fable.React.Props

// MODEL

type Model = int

type Msg =
| Increment
| Decrement

let init() : Model = 0

// UPDATE

let update (msg:Msg) (model:Model) =
    match msg with
    | Increment -> model + 1
    | Decrement -> model - 1

// VIEW (rendered with React)

let view (model:Model) dispatch =

  div []
      [ button [ OnClick (fun _ -> dispatch Increment) ] [ str "+" ]
        div [] [ str (string model) ]
        button [ OnClick (fun _ -> dispatch Decrement) ] [ str "-" ] ]

// App
Program.mkSimple init update view
|> Program.withReactSynchronous "elmish-app"
|> Program.withConsoleTrace
|> Program.run