Question

type Entity =
    abstract member newEntity: Entity
    abstract member clearEntity : Entity
    abstract member lastEntity : Entity
    abstract member loadData: Entity
    abstract member saveData: Entity -> unit
    abstract member deleteData: Entity -> unit

有什么办法可以避免重复写实体词？

type Entity =
    type T = Entity
    abstract member newEntity: T
    abstract member clearEntity : T
    abstract member lastEntity : T
    abstract member loadData: T
    abstract member saveData: T -> unit
    abstract member deleteData: T -> unit

我想要这样的实现，Scala应该能够做到

Answer 1

您不能将类型声明放在另一个内部。您可以做的是进行相互递归的类型声明：

type Entity =
    abstract member newEntity: T
    abstract member clearEntity : T
    abstract member lastEntity : T
    abstract member loadData: T
    abstract member saveData: T -> unit
    abstract member deleteData: T -> unit

and T = Entity

如何在f＃构造函数中声明类型别名？

1 个答案: