请参考对象定义中的对象类型 [英] refer to object type in object definition

问题描述

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注意：第一个例子有效。它显示我想要得到的。第二个例子表明我想在没有样板的情况下声明它，但是没有这样做。

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我只想简单的事情：

pre $ trait SelfTest [T<：SelfTest [T]] {_：T =>
def get：T = this
}
class Test扩展SelfTest [Test]
对象Test扩展测试


但没有样板类定义。例如：

  trait SelfTest [T<：SelfTest [T]] {_：T => 
 def get：T = this 
} 
对象Test extends SelfTest [Test.type] 
  

但这种方式被scala拒绝（涉及对象Test 的非法循环引用）。有没有像＃符号这样的魔术来表示创建的对象？

解决方案

这工作在scala 2.10 console ::

  scala>性状SelfTest [T <：SelfTest [_]] {_：T => def get：T = this} 
 defined trait SelfTest 
 
 scala> class Test扩展SelfTest [测试] 
定义的类测试
 
 scala> case对象t扩展Test 
定义模块t 
 
 scala> t.get 
 res1：Test = t 
  

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note: The first example works. It shows what I want to get. The second example shows that I'd like declare it without boilerplate but have failed to do so.

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I just want to get simple thing:

trait SelfTest[T <: SelfTest[T]] {_ : T =>
  def get : T = this
}
class Test extends SelfTest[Test]
object Test extends Test

but without boilerplate class definition. Something like this:

trait SelfTest[T <: SelfTest[T]] {_ : T =>
  def get : T = this
}
object Test extends SelfTest[Test.type]

But this way is rejected by scala (illegal cyclic reference involving object Test). Is there any magic like # sign to denote created object?

解决方案

This worked in scala 2.10 console::

scala> trait SelfTest[T<:SelfTest[_]] {_: T => def get:T = this }
defined trait SelfTest

scala> class Test extends SelfTest[Test]
defined class Test

scala> case object t extends Test
defined module t

scala> t.get
res1: Test = t

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