preg_replace with replacement function

Question

How do you use preg_replace with a function as the replacement parameter? I'm getting an error with this code.

function getInfo($id,$slot){
  if(!$id){ return '<b>Error</b> Id Not Returned. Please contact [e-mail] for more information.'; }
  $mm = mysql_query("SELECT * FROM `users` WHERE `id`='".$id."'");
  $mma = mysql_fetch_assoc($mm);
  $p = $mma[$slot];
  return $p;
  //return $id; <- Debug (Returns ID given)
}
$post = preg_replace(
  "/\[CallName]([^]]+)\[\/CallName\]/", 
  getInfo('\\1',"fullname"), 
  $post
);

Answer 1

I think you forgot e modifier (PREG_REPLACE_EVAL) in preg_replace function, this modifier is needed to evaluate replacement string as PHP code. It should be like this:

$post = preg_replace('~\[CallName\]([^]]+)\[/CallName\]~e', 'getInfo("$1", "fullname")', $post);

See this manual for for details.

Answer 2

The e modifer is now deprecated in favor of preg_replace_callback.

Sample usage:

$x = 'abcd-efg-hijk-lmnop';

$x = preg_replace_callback(
  '/-(.)/', //pattern
  function($matches) { //callback
    return strtoupper($matches[1]);
  }, 
  $x //subject
);

echo $x; //abcdEfgHijkLmnop