小编Jac*_*uls的帖子

当注册一个新的基本节点类型与registerNodeClass:它看起来像如果我重新使用创建的元素的变量名,然后自定义属性恢复到默认值.我实际上是想在一个循环中这样做,但这里有一个例子,我认为清楚地表明了我的意思:

<?php

class myDOMElement extends DOMElement
{
    public $myProp = 'Some default';
}

$doc = new DOMDocument();
$doc->registerNodeClass('DOMElement', 'myDOMElement');

$node = $doc->createElement('a');
$node->myProp = 'A';
$doc->appendChild($node);

# This seems to alter node A in $doc, not what I expected:
$node = $doc->createElement('b');
$node->myProp = 'B';
$doc->appendChild($node);

# Note: $nodeC instead of $node, this works fine. 
$nodeC = $doc->createElement('c');
$nodeC->myProp = 'C';
$doc->appendChild($nodeC);

foreach ($doc->childNodes as $n) {
    echo 'Tag ', $n->tagName, ' myProp:', PHP_EOL;
    var_dump($n->myProp);
}

为什么我得到"Some …

我正在尝试编写一个函数,给定树结构,返回该树的副本,但在特定索引处更改节点.这是我到目前为止:

#[derive(Clone)]
pub enum Node {
    Value(u32),
    Branch(u32, Box<Node>, Box<Node>),
}

fn main() {
    let root = Node::Branch(1, Box::new(Node::Value(2)), Box::new(Node::Value(3)));
    zero_node(&root, 2);
}

pub fn zero_node (tree: &Node, node_index: u8) -> Node {

    let mut new_tree = tree.clone();

    fn zero_rec (node : &mut Node, node_count : u8, node_index : u8) -> u8 {
        if (node_index == node_count) {
            match node {
                &mut Node::Value(_) => { *node = Node::Value(0); },
                &mut Node::Branch(_, ref mut left, ref mut right) => { *node …