[PHP-NOTES] note 130291 added to recursiveiteratoriterator.getsubiterator

$testArray = [
    'a' => [
        'b' => [
            'c' => 1
        ],
        'd' => [
            'e' => [
                'f' => 2
            ]
        ]
    ]
];

$modes = [
    'LEAVES_ONLY' => \RecursiveIteratorIterator::LEAVES_ONLY,
    'SELF_FIRST' => \RecursiveIteratorIterator::SELF_FIRST,
    'CHILD_FIRST' => \RecursiveIteratorIterator::CHILD_FIRST
];

function logIteratorTraversal(\RecursiveIteratorIterator $iterator, string $modeName)
{
    $maxDepth = 0;
    $log = [];

    foreach ($iterator as $key => $value) {
        $currentDepth = $iterator->getDepth();
        $maxDepth = max($maxDepth, $currentDepth);

        // 构建路径
        $path = [];
        for ($i = 0; $i <= $currentDepth; $i++) {
            $sub = $iterator->getSubIterator($i);
            $path[] = $sub->key();
        }

        $log[] = sprintf(
            "模式: %-11s | 当前深度: %d | 路径: %-16s | 类型: %s",
            $modeName,
            $currentDepth,
            implode('→', $path),
            is_array($value) ? '非叶子节点' : '叶子节点'
        );
    }

    echo "=== {$modeName} 模式遍历日志 ===\n";
    echo implode("\n", $log);
    echo "\n最大实际深度：" . ($maxDepth + 1) . "\n\n";
}

foreach ($modes as $name => $mode) {
    $iterator = new \RecursiveIteratorIterator(
        new \RecursiveArrayIterator($testArray),
        $mode,
        \RecursiveIteratorIterator::CATCH_GET_CHILD
    );
    logIteratorTraversal($iterator, $name);
}

=== LEAVES_ONLY 模式遍历日志 ===
模式: LEAVES_ONLY | 当前深度: 2 | 路径: a→b→c        | 类型: 叶子节点
模式: LEAVES_ONLY | 当前深度: 3 | 路径: a→d→e→f    | 类型: 叶子节点
最大实际深度：4

=== SELF_FIRST 模式遍历日志 ===
模式: SELF_FIRST  | 当前深度: 0 | 路径: a                | 类型: 非叶子节点
模式: SELF_FIRST  | 当前深度: 1 | 路径: a→b            | 类型: 非叶子节点
模式: SELF_FIRST  | 当前深度: 2 | 路径: a→b→c        | 类型: 叶子节点
模式: SELF_FIRST  | 当前深度: 1 | 路径: a→d            | 类型: 非叶子节点
模式: SELF_FIRST  | 当前深度: 2 | 路径: a→d→e        | 类型: 非叶子节点
模式: SELF_FIRST  | 当前深度: 3 | 路径: a→d→e→f    | 类型: 叶子节点
最大实际深度：4

=== CHILD_FIRST 模式遍历日志 ===
模式: CHILD_FIRST | 当前深度: 2 | 路径: a→b→c        | 类型: 叶子节点
模式: CHILD_FIRST | 当前深度: 1 | 路径: a→b            | 类型: 非叶子节点
模式: CHILD_FIRST | 当前深度: 3 | 路径: a→d→e→f    | 类型: 叶子节点
模式: CHILD_FIRST | 当前深度: 2 | 路径: a→d→e        | 类型: 非叶子节点
模式: CHILD_FIRST | 当前深度: 1 | 路径: a→d            | 类型: 非叶子节点
模式: CHILD_FIRST | 当前深度: 0 | 路径: a                | 类型: 非叶子节点
最大实际深度：4
----
Server IP: 45.112.84.4
Probable Submitter: 80.90.5.137 (proxied: 39.166.18.151)
----
Manual Page -- https://php.net/manual/en/recursiveiteratoriterator.getsubiterator.php
Edit        -- https://main.php.net/note/edit/130291
Del: integrated  -- https://main.php.net/note/delete/130291/integrated
Del: useless     -- https://main.php.net/note/delete/130291/useless
Del: bad code    -- https://main.php.net/note/delete/130291/bad+code
Del: spam        -- https://main.php.net/note/delete/130291/spam
Del: non-english -- https://main.php.net/note/delete/130291/non-english
Del: in docs     -- https://main.php.net/note/delete/130291/in+docs
Del: other reasons-- https://main.php.net/note/delete/130291
Reject      -- https://main.php.net/note/reject/130291
Search      -- https://main.php.net/manage/user-notes.php