group-node-term-links-by-vocab.php

<?php

/**
 * Screenshot: http://imagebin.org/101526
 */

/**
 * Implements hook_link_alter().
 */
function hook_link_alter(&$links, $node, $comment = NULL) {
  $links2 = array();
  $vocabs = array();
  foreach (array_keys($links) as $k) {
    if (strpos($k, 'taxonomy_term_') === 0) {
      $tid = str_replace('taxonomy_term_', '', $k);
      $term = $node->taxonomy[$tid];
      
      if (!isset($links2[$term->vid])) {
        $vocabs[$term->vid] = taxonomy_vocabulary_load($term->vid);
        $links2[$term->vid] = array(
          'title' => $vocabs[$term->vid]->name,
        );
      }
      
      $links2[$term->vid]['#children'][] = $links[$k];
    }
  }

  if (!empty($links2)) {
    foreach (array_keys($links2) as $k) {
      $links2[$k] = array(
        'title' => 
          "<span class=\"vocabulary-name\">{$links2[$k]['title']}:</span>" 
            . theme('links', $links2[$k]['#children']),
        'html' => TRUE,
      );
    }
    
    $links = $links2;
  }
}