/**
  * Creates a map of $sourceId => array of sections to use.
  * Each section resides in a file named docs/abbrev/<section>.conf (these are loaded lazily).
  */
 static function loadAbbreviationsIndex()
 {
     if (!self::$ABBREV_INDEX) {
         self::$ABBREV_INDEX = array();
         $raw = parse_ini_file(util_getRootPath() . "docs/abbrev/abbrev.conf", true);
         foreach ($raw['sources'] as $sourceId => $sectionList) {
             self::$ABBREV_INDEX[$sourceId] = preg_split('/, */', $sectionList);
         }
     }
     return self::$ABBREV_INDEX;
 }