Question

我有很多方法如下

def functionOne(param1: String, param2: Int): ReturnTypeOne = {
  doSomethingWith(param1, param2, new ReturnTypeOne)
}

def functionTwo(param1: String, param2: Int): ReturnTypeTwo = {
  doSomethingWith(param1, param2, new ReturnTypeTwo)
}
.....
def functionN(param1: String, param2: Int): ReturnTypeN = {
  doSomethingWith(param1, param2, new ReturnTypeN) 
}

有没有办法在Scala中推广这些方法？有什么建议吗？

Answer 1

不太确定“概括”是什么意思。这样的事可能吗？

trait F[A] {
  def f(x: String, y: Int): A
}

object F {
  def f[A](x: String, y: Int)(implicit ev: F[A]) = ev.f(x, y)

  implicit object FInt extends F[Int] {
    def f(x: String, y: Int) = y
  }

  implicit object FString extends F[String] {
    def f(x: String, y: Int) = x
  }
}

import F._

f[Int]("123", 1) //> 1
f[String]("123", 1) //> "123"

Answer 2

也许将它们分组：

def functions (param1: String, param2: Int) = new {
  def one: ReturnTypeOne = ???
  def two: ReturnTypeTwo = ???
  def n: ReturnTypeN = ???
}

...
functions("a", 4).one

functions("b", 7).two

使用共同签名来概括方法

2 个答案: