C#实现递归调用的Lambda表达式

    int i = 1;
    RecursiveRun(self =>
        {
            Console.WriteLine("hello world " + i++);
            self();
        });

    static void RecursiveRun(Action<Action> action)
    {
        action(() => RecursiveRun(action));
    }

    static void RecursiveRun<T>(T obj, Action<T, Action<T>> action)
    {
        action(obj, o => RecursiveRun(o, action));
    }

    class BinTree
    {
        public int Value { get; set; }
        public BinTree Left { get; set; }
        public BinTree Right { get; set; }

        public BinTree(int value)
        {
            this.Value = value;
        }

        public void Accept(Action<BinTree> visitor)
        {
            visitor(this);
        }

        public void Accept(Action<BinTree, Action<BinTree>> visitor)
        {
            visitor(this, node => node.Accept(visitor));
        }

        public override string ToString()
        {
            return Value.ToString();
        }
    }

    var nodes = Enumerable.Range(0, 5).Select(i => new BinTree(i)).ToArray();

    nodes[0].Left = nodes[1];
    nodes[0].Right = nodes[2];
    nodes[1].Left = nodes[3];
    nodes[1].Right = nodes[4];

    nodes[0].Accept((node, visitor) =>
        {
            Console.WriteLine(node.Value);
            if (node.Left != null)
                visitor(node.Left);
            if (node.Right != null)
                visitor(node.Right);
        });