PHP递归不停止

Question

不确定我在这个递归函数上做错了什么。我有一个带有网站树的数组，我正在寻找的页面可以无限​​深。该函数遍历所有可能性，但有时在找到正确的“页面”时不会停止。

数组

$haystack = array(
    array("id" => 1,"parent" => 0,"route" => "home","children" => array()),
    array("id" => 2,"parent" => 0,"route" => "news","children" => array()),
    array("id" => 3,"parent" => 0,"route" => "photography","children" => array(
                array("id" => 6,"parent" => 3,"route" => "photography/portraits","children" => array()),
                array("id" => 7,"parent" => 3,"route" => "photography/countries","children" => array()),
                array("id" => 8,"parent" => 3,"route" => "photography/landscapes","children" => array(
                                array("id" => 9,"parent" => 8,"route" => "photography/landscapes/city","children" => array()),
                                array("id" => 10,"parent" => 8,"route" => "photography/landscapes/wilderness","children" => array())
                            )
                )
        )
    ),
    array("id" => 4,"parent" => 0,"route" => "about","children" => array()),
    array("id" => 5,"parent" => 0,"route" => "contact","children" => array()),
);

递归函数

function recurse($needle = -1, $haystack = NULL){
    $_tmp = array();

    foreach($haystack as $key => $item)
    {
        echo $needle ." === ". $item["id"] . "<br/>";

        if((string)$item["id"] === (string)$needle){
            echo "Found: " . $needle . "<br/><br/>";
            $_tmp = $item;
            break;
            //return $item;   <-- this doesn't work either
        } else {
            $_tmp = recurse($needle, $item["children"]);
        }
    }
    return $_tmp;
}

测试用例:

$test = recurse(3);
print_r($test);

$test = recurse(7);
print_r($test);

$test = recurse(9);
print_r($test);

最后的测试输出:

9 === 1
9 === 2
9 === 4
9 === 7
9 === 8
9 === 11
9 === 12
9 === 13
9 === 14
9 === 15
9 === 3
9 === 9
Found: 9  <-- should stop here, but continues

9 === 5
9 === 6
Array
(
)

Answer 1

它返回但在其他递归框架中继续。例如，调用:1 -> 2 -> 3 -> 4。从 4 返回但 3 (1 -> 2 -> 3) 继续执行循环。