隐式转换以实例化密封类

发布于 2024-09-15 12:14:26 字数 545 浏览 7 评论 0原文

我有这个继承权

sealed abstract class MyValue
case class MyString(s:String) extends MyValue
case class MyBoolean(b:Boolean) extends MyValue
case class MyR(m1:MyValue, m2:MyValue) extends MyValue
case class MyU(m1:MyValue, m2:MyValue) extends MyValue
/* ... */

，

implicit def string2myString(s:String) = MyString(s)
implicit def boolean2myBoolean(b:Boolean) = MyBoolean(b)

但是，我想这样做：

"hello" MyR true // R(MyString("hello"), MyValue(true))

我该怎么做？

原文

I have this inheritance

sealed abstract class MyValue
case class MyString(s:String) extends MyValue
case class MyBoolean(b:Boolean) extends MyValue
case class MyR(m1:MyValue, m2:MyValue) extends MyValue
case class MyU(m1:MyValue, m2:MyValue) extends MyValue
/* ... */

and

implicit def string2myString(s:String) = MyString(s)
implicit def boolean2myBoolean(b:Boolean) = MyBoolean(b)

But, I want to do this:

"hello" MyR true // R(MyString("hello"), MyValue(true))

How I can do it?

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请叫√我孤独 2024-09-22 12:14:26

怎么样：

class MyRBuilder(mv1: MyValue) { 
  def this(s:String) = this(MyString(s))
  def this(b:Boolean) = this(MyBoolean(b))  
  def R(mv2:MyValue) = MyR(mv1, mv2)
}

implicit def stringToMyRBuilder(s:String) = new MyRBuilder(s)
implicit def boolToMyRBuilder(b:Boolean) = new MyRBuilder(b)

"hello" MyR true
//res2: MyR = MyR(MyString(hello),MyBoolean(true))

[编辑]我认为关于你的第二个问题兰德尔是对的。如果您只想要干净 DSL 的“光学效果”，您可以考虑使用符号而不是字符串，例如 'hello 而不是 "hello"

How about this:

class MyRBuilder(mv1: MyValue) { 
  def this(s:String) = this(MyString(s))
  def this(b:Boolean) = this(MyBoolean(b))  
  def R(mv2:MyValue) = MyR(mv1, mv2)
}

implicit def stringToMyRBuilder(s:String) = new MyRBuilder(s)
implicit def boolToMyRBuilder(b:Boolean) = new MyRBuilder(b)

"hello" MyR true
//res2: MyR = MyR(MyString(hello),MyBoolean(true))

[Edit] I think regarding your second question Randall is right. If you just want the "optical effect" of a clean DSL, you might consider to use Symbols instead of Strings, e.g. 'hello instead of "hello"

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