Swift中基于协议的通用树结构-Generic,Protocol-basedTreeStructureinSwift

So a Tree is either a Leaf with a content of a generic type, or a Branch with a left & right Tree.

因此,Tree可以是具有泛型类型内容的Leaf,也可以是具有左右树的分支。

I'm bumping up against the type system in Swift, so I'm not sure what the appropriate form should be. I have:

我碰到了Swift中的类型系统,所以我不确定应该采用什么样的形式。我有:

protocol Tree {
    associatedtype Element: CustomStringConvertible
}

struct Leaf: Tree {
    typealias Element = LeafElement
    let content: Element
}

struct Branch: Tree {
    typealias Element = BranchElement
    let left: Tree
    let right: Tree
}

At this point, the above is many iterations of banging my head against the wall, so it's probably way off at this point. Leaf seems to be fine, but Branch fails with

在这一点上,上面是我的头撞墙的许多次迭代,所以在这一点上它可能已经过时了。 Leaf看起来很好,但Branch失败了

Protocol 'Tree' can only be used as a generic constraint because it has Self or associated type requirements

And recommendations would be appreciated.

建议将不胜感激。

1 个解决方案