PHP：如何将变量从正则表达式替换传递给函数？

Question

I would like to have a regular expression that takes

[QUOTE=3]

and transforms it into

<div class="quoted"><div class="quotation-author">Originally written by <strong>AUTHOR_WITH_ID=3</strong></div>

I got it almost right, but I'm unable to pass a variable to a function that gets author name.

$comment = preg_replace('/\[\s*QUOTE=(\d+)\s*\]/i', '<div class="quoted"><div class="quotation-author">Originally written by <strong>'.get_comment_author((int)'$1').'</strong></div>', $comment);

Answer 1

The replacement:

'<div class="quoted"><div class="quotation-author">Originally written by <strong>'.get_comment_author((int)'$1').'</strong></div>'

does not happen dynamically; it is evaluated, then passed as an argument. Use preg_replace_callback to call a function for each match as follows:

$comment = preg_replace_callback('/\[\s*QUOTE=(\d+)\s*\]/i', function($m) {
    return '<div class="quoted"><div class="quotation-author">Originally written by <strong>'.get_comment_author((int) $m[1]).'</strong></div>';
}, $comment);

Answer 2

You can't use preg_replace for this, as the call to get_comment_author (and the (int) cast) happens before preg_replace is ran.

Try using preg_replace_callback :

$comment = preg_replace_callback('/\[\s*QUOTE=(\d+)\s*\]/i', function($a){
    return '<div class="quoted"><div class="quotation-author">Originally written by <strong>'.get_comment_author($a[1]).'</strong></div>';
}, $comment);

Note: Depending on what get_comment_author does, you shouldn't need the (int) cast.