如何在 Scala 中定义赋值运算符？

Question

例如，我在下面的包装器 class 中为 Double 定义了一个 +* 加权和运算符：

  class DoubleOps(val double: Double) {
    def +*(other: DoubleOps, weight: Double): DoubleOps =
      new DoubleOps(this.double + other.double * weight)
  }

  object DoubleOps {
    implicit def DoubleToDoubleOps(double: Double) = new DoubleOps(double)
  }

根据这个定义，我可以进行如下计算：

var db: DoubleOps = 1.5
import DoubleOps._
db = db +* (2.0, 0.5)
println(db)

有没有一种方法可以使用赋值运算符计算 db 以获得结果，比如定义一个 +*=，这样我就可以使用：

db +*= (2.0, 0.5)

这可能吗？

Answer 1

import scala.languageFeature.implicitConversions

class DoubleOps(var double: Double) {
  def +*(other: DoubleOps, weight: Double): DoubleOps =
    new DoubleOps(this.double + other.double * weight)

  def +*=(other: DoubleOps, weight: Double): Unit = {
    this.double = this.double + other.double * weight
  }
}

object DoubleOps {
  implicit def DoubleToDoubleOps(double: Double) = new DoubleOps(double)
}

val d: DoubleOps = 1.5

d +*= (2.0, 0.5)

如何在 Scala 中定义赋值运算符？

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