Integration with RealName module

If you have RealName installed you will get access to the [realame] token.

in my case on /admin/settings/filters/[id]/configure
Output:
Prefix = ""
Content = [realname]
Suffix = ""

I made a small modification to Mentions to integrate it with RealName, and to support RealNames with spaces when no end delimiter is given.
I am quite new to drupal so I would not recommend it to produlction use and would be very happy if more experienced ones reviewed my code...

first add a small helper class as wordcountheap.php to the module root for real name sorting:

<?php

class WordCountHeap extends SplMaxHeap {
  public function compare($value1, $value2) {
    if ( $value1["word_count"] != $value2["word_count"] ) {
      return ( $value1["word_count"] - $value2["word_count"] );
    }
    else {
      return ( strlen($value1["name"]->realname) - strlen($value2["name"]->realname) );
    }
  }
}

?>

Then replace mentions_find_users with this funtion:

<?php 
function mentions_find_users($text) {
  $users = array();

  // If RealName module is installed and we have no delimiter characters
  // we apply a different method to extract mentions based on names starting with the word

  if ( module_exists("realname") && ( variable_get('mentions_input_suffix',']') == '' ) ) {
    $mentions = array();
    $mention_start_position = 0;

  // We get the words starting with the mention prefix ('@' by default)
    while ($mention_start_position !== false) {
      $mention_start_position = strpos($text, variable_get('mentions_input_prefix','@'), $mention_start_position);
      if ($mention_start_position !== false)  {
        if ( preg_match( '/' . variable_get('mentions_input_prefix','@') . '(\w+)[ :,\.<&\?!]*/',$text,$match ) ) {
          $word = $match[1];
          array_push($mentions,$word);
          $mention_start_position += strlen($word);
        }
      }
    }
    // We set up a heap to sort our names by word count
    include_once "wordcountheap.php";
    $similar_names = new WordCountHeap;

    // We search for user real names which begin with the mentioned word, then we put them into the heap 
    // with the key "name", together with an auxiliary value "word_count". The heap sorts itself by "word_count" or length when equal.
    // This is necessary to get the longest names go first. (To prevent "John Smith" come before and overrde "John Smith jr.")
    foreach ($mentions as $mention) {

      // We search for real names that begin with the prefixed word then put them into the heap
      $query = db_query("SELECT realname, uid FROM {realname} WHERE realname LIKE '%s%'", $mention );
      while ( $name = db_fetch_object($query) ) {
        $similar_names->insert( array("name" => $name, "word_count" => str_word_count($name->realname) ) );
      }

      // If there are real names beginning with the word
      if (!$similar_names->isEmpty()) {
        // And if we find any of them in the text, we add them to the mentioned users list
        foreach ($similar_names as $name_object) {
          if (preg_match('/'.variable_get('mentions_input_prefix','@').($name_object["name"]->realname).'/',$text,$match) ) {
            $user = user_load(array('uid' => $name_object["name"]->uid));
            if (is_object($user)) {
              $users[] = array(
                'text' => $match[0],
                'user' => $user
              );
              break;
            }
          }
        }
      }
      // If we have no similar real names we try to interpret the word as a username 
      else {
        $user = user_load( array('name' => $mention) );
        if (is_object($user)) {
          $users[] = array(
            'text' => variable_get('mentions_input_prefix','@').$mention,
            'user' => $user
          );
        }
      }
    }
  }
  else {
// This is the the original function except for the module_exists("realname") branch of course.

    $pattern = variable_get('mentions_input_suffix', ']') != ''
      ? '/\B('. preg_quote(variable_get('mentions_input_prefix', '[@')) .'|'. preg_quote(check_plain(variable_get('mentions_input_prefix', '[@'))) .')(\#?.*?)('. preg_quote(variable_get('mentions_input_suffix', ']')) .'|'. preg_quote(check_plain(variable_get('mentions_input_suffix', ']'))) .')/'
      : '/\B('. preg_quote(variable_get('mentions_input_prefix', '[@')) .'|'. preg_quote(check_plain(variable_get('mentions_input_prefix', '[@'))) .')(\#?\w*)/';

    if (preg_match_all($pattern, $text, $matches, PREG_SET_ORDER)) {
      foreach ($matches as $match) {
        if ( drupal_substr($match[2], 0, 1) == '#') {
          $user = user_load( array('uid' => drupal_substr($match[2], 1)) );
        }
        else {
          // If RealName module is installed we try to interpret name as a realname.
          if ( module_exists("realname") ) {
            $query = db_query("SELECT uid FROM {realname} WHERE realname = '%s'", $match[2] );
            if ($uid = db_fetch_object($query)->uid) {
              $user = user_load(array('uid' => $uid));
            }
            else {
            $user = user_load(array('name' => $match[2]));
            }
          }
          else {
            $user = user_load(array('name' => $match[2]));
          }
        }

        if (is_object($user)) {
          $users[] = array(
            'text' => $match[0],
            'user' => $user
          );
        }
      }
    }
  }
  return $users;
}

?>

Works with D7 with nothing needed to be done, may work in D6 as well as you can change the output value token.