package chapter2.demo5

object DemoCurrying {
  def main(args: Array[String]): Unit = {

    def add(x: Int, y: Int): Int = x + y

    println(add(2, 3))

    def addTaowa(x: Int): Int => Int = {
      def add(y: Int): Int = x + y

      add
    }

    println(addTaowa(2)(3))

    def addTaowa2(x: Int): Int => Int = {
      (y: Int) => x + y
    }

    println(addTaowa2(2)(3))
    //  def add(x: Int, y: Int): Int = x + y
    def addCurrying(x: Int)(y: Int): Int = {
      x + y
    }


    val addLambda = (x:Int,y:Int) => x+y
    // add是普通函数，可以通过scala自带的curried方法转成一个柯里化函数
    val curriedAdd = addLambda.curried
    addLambda(1,2)
    curriedAdd(1)(2)

    println(addCurrying(2)(3))
    val add2 = addCurrying(2) _

    add2(3)
    add2(4)

    // 柯里化的使用场景
    // 柯里化可以部分记住参数的固定值
    // debug info warn error
    def log(level: String)(message: String): Unit = {
      println(s"[$level] - $message")
    }
    log("info")("这是一条info级别的日志")
    log("warn")("这是一条warn级别的日志")
    log("error")("这是一条error级别的日志")

    val infoLog = log("info") _
    val warnLog = log("warn") _
    val errorLog = log("error") _

    // 闭包
    infoLog("普通日志")
    warnLog("告警日志")
    errorLog("错误日志")


  }
}