Scala 任何数字类型的隐式转换

Question

我目前正在学习 Scala 编程语言(顺便说一句，我很喜欢它)并且最近发现了隐式转换。所以我有我的类 Complex 及其伴随对象。在我的伴侣对象中，我想要这些隐式转换:

    implicit def convertToComplex(x: Double) = new Complex(x, 0);
    implicit def convertToComplex(x: Int) = new Complex(x, 0);
    implicit def convertToComplex(x: Float) = new Complex(x, 0);
    implicit def convertToComplex(x: Short) = new Complex(x, 0);
    implicit def convertToComplex(x: Long) = new Complex(x, 0);

为了不让我的 Complex number 类因加号类型的 +、-、* 和/重载而膨胀。

所以我的问题是:

有没有更短的方法来使用某种语法糖来编写隐式转换？ (我的意思是没有所有的重载...)

提前致谢。

Answer 1

你可以这样做

object ConvertComplex {
  case class Complex[T: Numeric](x: T, y: Int) {

    val nX = implicitly[Numeric[T]]

    def doSomething = nX.toInt(x) * y
    def doSomethingElse = nX.plus(x, nX.fromInt(y))
  }

  object Complex {
    implicit def convertToComplect[T: Numeric](x: T) = Complex(x, 0)
  }

}

以及测试结果:

def doSomething[T: Numeric](x: Complex[T]) = x.doSomething
def doSomethingElse[T: Numeric](x: Complex[T]) = x.doSomething

val double = 1: Double    //> double  : Double = 1.0
val int = 1: Int          //> int  : Int = 1
val float = 1: Float      //> float  : Float = 1.0
val short = 1: Short      //> short  : Short = 1
val long = 1: Long        //> long  : Long = 1

doSomething(double)       //> res0: Int = 0
doSomething(int)          //> res1: Int = 0
doSomething(float)        //> res2: Int = 0
doSomething(short)        //> res3: Int = 0
doSomething(long)         //> res4: Int = 0

doSomethingElse(double)   //> res5: Double = 1.0
doSomethingElse(int)      //> res6: Int = 1
doSomethingElse(float)    //> res7: Float = 1.0
doSomethingElse(short)    //> res8: Short = 1
doSomethingElse(long)     //> res9: Long = 1