AST Protocol

gistfile1.txt

protocol AST {
    associatedtype NodeType = Self
    var children: [NodeType] { get }
}

extension AST where NodeType: AST, NodeType.NodeType == NodeType {
    func traverse(check: (Self.NodeType) -> Bool) {
        for child in children {
            if check(child) {
                child.traverse(check: check)
            }
        }
    }
}

class Node: AST {
    var children: [Node] = []
}

let n = Node()
n.children = [Node(), Node()]
n.traverse() { node in
    return false
}