Seven More Languages in Seven Weeks （读书笔记）：Elm

Elm

1. Day 1
   1. > [1, "2"] //强类型，要求数组内元素必须是同一个类型？
   2. Building Algebraic Data Types：> type Color = Black | White //Haskell语法？
      1. type List = Nil | Cons Int List
      2. type List a = Empty | Cons a (List a)
   3. Using Records
      1. > blackQueen = {color=Black, piece=Queen}
      2. > .color blackQueen //这是学习的Clojure？
   4. 函数
      1. > add x y = x + y
      2. > anonymousInc = \x -> x + 1
      3. > 5 |> anonymousInc |> double //这是学习的Elixir？
         1. > double <| anonymousInc <| 5
   5. 模式匹配
      1. 简化函数定义：> first (head::tail) = head
2. Day 2
   1. 信号：A signal represents I/O as a value that varies over time（stream？Rx Observable？）
      1. main = Signal.map show Mouse.position
      2. count signal = Signal.foldp (\_ n -> n + 1) 0 signal
   2. 组合信号
      1. clickPosition = Signal.sampleOn Mouse.clicks Mouse.position //当clicks更新时采样position
3. Day 3
   1. games/skeleton.elm
      1. delta = inSeconds <~ fps n
      2. input = sampleOn delta (...)
      3. main = map display gameState
      4. gameState = foldp stepGame initialGameState input
   1. 略