很简单,有没有办法结合构造函数参数和抽象类型?例如,我想做的事情
class A(t: Seq[T]) { type T }
解决方法
该类的成员不在构造函数的参数声明中.
这是尽可能接近:
scala> trait T { type T; val a: T } defined trait T scala> def A[X](x: X) = new T { type T = X; val a = x } A: [X](x: X)Object with T{type T = X} scala> A[Int](0) res0: Object with T{type T = Int} = $anon$1@3bd29ee4 scala> A[String](0) <console>:10: error: type mismatch; found : Int(0) required: String A[String](0) ^ scala> class AA[X](val a: X) extends T { type T = X } defined class AA scala> new AA[Int](0) res5: AA[Int] = AA@1b3d4787 scala> new AA[String](0) <console>:10: error: type mismatch; found : Int(0) required: String new AA[String](0) ^