通过特征覆盖方法时如何调用超级方法 [英] How to call super method when overriding a method through a trait

问题描述

似乎可以在具有如下特征的类上更改方法的实现:

It would appear that it is possible to change the implementation of a method on a class with a trait such as follows:

trait Abstract { self: Result =>
    override def userRepr = "abstract"
}

abstract class Result {
    def userRepr: String = "wtv"
}

case class ValDefResult(name: String) extends Result {
    override def userRepr = name
}

val a = new ValDefResult("asd") with Abstract
a.userRepr

可在此处获得实时代码: http://www.scalakata.com/52534e2fe4b0b1a1c4daa436

Live code is available here: http://www.scalakata.com/52534e2fe4b0b1a1c4daa436

但是现在我想调用该函数的先前或超级实现，如下所示:

But now I would like to call the previous or super implementation of the function such as follows:

trait Abstract { self: Result =>
    override def userRepr = "abstract" + self.userRepr
}

或

trait Abstract { self: Result =>
    override def userRepr = "abstract" + super.userRepr
}

但是，这些选择都不能编译.知道如何实现吗?

However, none of these alternatives compile. Any idea how this could be accomplished?

推荐答案

这是我一直在寻找的答案.谢谢Shadowlands通过Scala的abstract override功能为我指明了正确的方向.

Here is the answer I was looking for. Thank you Shadowlands for pointing me in the right direction with Scala's abstract override feature.

trait Abstract extends Result {
    abstract override def userRepr = "abstract " + super.userRepr
}

abstract class Result {
    def userRepr: String = "wtv"
}

case class ValDefResult(name: String) extends Result {
    override def userRepr = name
}

val a = new ValDefResult("asd") with Abstract
a.userRepr

可在此处获得实时代码: http://www.scalakata.com/52536cc2e4b0b1a1c4daa4a4

Live code is available here: http://www.scalakata.com/52536cc2e4b0b1a1c4daa4a4

对于令人困惑的示例代码很抱歉，我正在编写一个处理Scala AST的库，并且没有足够的灵感来更改名称.

Sorry for the confusing example code, I am writing a library that deals with the Scala AST and was not inspired enough to change the names.

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