PHP 和正则表达式 : Split a string by commas that are not inside brackets (and also nested brackets)

Question

两天前，我开始研究代码解析器，但遇到了困难。

如何用不在括号内的逗号分隔字符串，让我告诉你我的意思:

我要解析这个字符串:

one, two, three, (four, (five, six), (ten)), seven

我想得到这个结果:

array(
 "one"; 
 "two"; 
 "three"; 
 "(four, (five, six), (ten))"; 
 "seven"
)

但我得到的是:

array(
  "one"; 
  "two"; 
  "three"; 
  "(four"; 
  "(five"; 
  "six)"; 
  "(ten))";
  "seven"
)

我如何在 PHP RegEx 中执行此操作。

提前致谢!

Answer 1

您可以更轻松地做到这一点:

preg_match_all('/[^(,\s]+|\([^)]+\)/', $str, $matches)

但是如果你使用真正的解析器会更好。也许是这样的:

$str = 'one, two, three, (four, (five, six), (ten)), seven';
$buffer = '';
$stack = array();
$depth = 0;
$len = strlen($str);
for ($i=0; $i<$len; $i++) {
    $char = $str[$i];
    switch ($char) {
    case '(':
        $depth++;
        break;
    case ',':
        if (!$depth) {
            if ($buffer !== '') {
                $stack[] = $buffer;
                $buffer = '';
            }
            continue 2;
        }
        break;
    case ' ':
        if (!$depth) {
            continue 2;
        }
        break;
    case ')':
        if ($depth) {
            $depth--;
        } else {
            $stack[] = $buffer.$char;
            $buffer = '';
            continue 2;
        }
        break;
    }
    $buffer .= $char;
}
if ($buffer !== '') {
    $stack[] = $buffer;
}
var_dump($stack);