scala學習----柯里化

1、鴨子類型，走起來像鴨子，叫起來像鴨子，就是鴨子。函數中使用{ def close(): Unit }作為參數類型，因此任何含有此函數的類都可以作為參數傳遞。好處是不必使用繼承特性。

 1 def withClose(closeAble: { def close(): Unit }, 
 2     op: { def close(): Unit } => Unit) {
 3     try {
 4         op(closeAble)
 5     } finally {
 6         closeAble.close()
 7     }
 8 }
 9 
10 class Connection {
11     def close() = println("close Connection")
12 }
13 
14 val conn: Connection = new Connection()
15 withClose(conn, conn =>
16     println("do something with Connection"))

2、柯里化技術（currying）def add(x: Int, y: Int) = x + y 是普通函數 def add(x: Int) = (y:Int) => x + y 柯里化後的結果。相當於返回一個匿名函數。def add(x: Int)  (y:Int) => x + y 是簡寫。這就是柯里化。柯里化讓我們構造出更像原生語言提供的功能的代碼。

 1 def withClose(closeAble: { def close(): Unit })
 2     (op: { def close(): Unit } => Unit) {
 3     try {
 4         op(closeAble)
 5     } finally {
 6         closeAble.close()
 7     }
 8 }
 9 
10 class Connection {
11     def close() = println("close Connection")
12 }
13 
14 val conn: Connection = new Connection()
15 withClose(conn)(conn =>
16     println("do something with Connection"))