使用正则表达式的深度（无限）嵌套拆分词

Question

重要编辑： 由于许多人说应该避免这种情况，并且几乎无法使用 RegEx，所以我将允许您使用其他一些解决方案。从现在开始，任何解决方案都可以用作答案，最终成为解决方案。谢谢！

假设我有：

$line = "{ It is { raining { and streets are wet } | snowing { and streets are { slippy | white }}}. Tomorrow will be nice { weather | walk }. }" 

期望的输出：

It is raining and streets are wet. Tomorrow will be nice weather.
It is raining and streets are wet. Tomorrow will be nice walk.
It is snowing and streets are slippy. Tomorrow will be nice weather.
It is snowing and streets are slippy. Tomorrow will be nice walk.
It is snowing and streets are white. Tomorrow will be nice weather.
It is snowing and streets are white. Tomorrow will be nice walk. 

使用this answer 到我上一个问题的代码，我目前能够拆分单词但无法找出嵌套值。有人可以帮我解决我下面的问题。我很确定我应该在某处实现for 循环以使其工作，但我不明白在哪里。

$line = "{This is my {sentence|statement} I {wrote|typed} on a {hot|cold} {day|night}.}";
 $matches = getMatches($line);
 printWords([], $matches, $line);


function getMatches(&$line) {
    $line = trim($line, '{}'); 
    $matches = null;
    $pattern = '/\{[^}]+\}/';

    preg_match_all($pattern, $line, $matches);

    $matches = $matches[0];

    $line = preg_replace($pattern, '%s', $line);

    foreach ($matches as $index => $match) {
        $matches[$index] = explode('|', trim($match, '{}'));
    }

    return $matches;
}


function printWords(array $args, array $matches, $line) {
    $current = array_shift($matches);
    $currentArgIndex = count($args);

    foreach ($current as $word) {
        $args[$currentArgIndex] = $word;

        if (!empty($matches)) {
                printWords($args, $matches, $line);
        } else {
                echo vsprintf($line, $args) . '<br />';
        }
    }
}

我想到的一种方法是使用lexer 技术，如逐字符读取，创建适当的字节码，然后循环遍历它。这不是正则表达式，但它应该可以工作。

Answer 1

这个类完成了工作，尽管不确定它的效率如何：

class Randomizer {

    public function process($text) {
        return preg_replace_callback('/\{(((?>[^\{\}]+)|(?R))*)\}/x', array($this, 'replace'), $text);
    }

    public function replace($text) {
        $text = $this->process($text[1]);
        $parts = explode('|', $text);
        $part = $parts[array_rand($parts)];
        return $part;
    }
}

要使用它，您只需这样做：

$line = "{This is my {sentence|statement} I {wrote|typed} on a {hot|cold} {day|night}.}";
$randomizer = new Randomizer( );
echo   $randomizer->process($line);

在正则表达式方面我不是最好的，所以我无法真正解释为什么那个特定的正则表达式有效，很抱歉。

顺便说一下，它返回随机字符串而不是所有可能的字符串。如果您需要所有字符串而不是随机字符串，请告诉我。我会更新答案..