php正则表达式匹配字符串，如果不在HTML标记中

Question

I'm trying to solve this bug in Drupal's Hashtags module: http://drupal.org/node/1718154

I've got this function that matches every word in my text that is prefixed by "#", like #tag:

function hashtags_get_tags($text) {
    $tags_list = array();
    $pattern = "/#[0-9A-Za-z_]+/";
    preg_match_all($pattern, $text, $tags_list);
    $result = implode(',', $tags_list[0]);
    return $result;
    }

I need to ignore internal links in pages, such as <a href="#reference">link</a>, or, more in general, any word prefixed by # that appears inside an HTML tag (so preceeded by < and followed by >).

Any idea how can I achieve this?

Answer 1

Can you strip the tags first because matching (using the strip_tags function)?

function hashtags_get_tags($text) {

    $text = strip_tags($text);

    $tags_list = array();
    $pattern = "/#[0-9A-Za-z_]+/";
    preg_match_all($pattern, $text, $tags_list);
    $result = implode(',', $tags_list[0]);
    return $result;
}

A regular expression is going to be tricky if you want to only match hashtags that are not inside an HTML tag.