In order to extend another section, a section defines the "_extends" property having a value of the section name from which the extending section inherits values.
Note that the keys in $section will override any keys of the same name in the sections that have been included via "_extends".
  134             #require_once 'Zend/Config/Exception.php';   139         $allowModifications = 
false;
   144                 switch (strtolower($key)) {
   145                     case 'allow_modifications':
   146                     case 'allowmodifications':
   147                         $allowModifications = (bool) 
$value;
   151                         $this->_skipExtends = (bool) 
$value;
   153                     case 'ignore_constants':
   154                     case 'ignoreconstants':
   155                         $ignoreConstants = (bool) 
$value;
   168         set_error_handler(array($this, 
'_loadFileErrorHandler'));
   170         restore_error_handler();
   173         if ($this->_loadFileErrorStr !== 
null) {
   174             #require_once 'Zend/Config/Exception.php';   189             #require_once 'Zend/Config/Exception.php';   193         if (
null === $section) {
   194             $dataArray = array();
   195             foreach (
$config as $sectionName => $sectionData) {
   198             parent::__construct($dataArray, $allowModifications);
   199         } 
elseif (is_array($section)) {
   200             $dataArray = array();
   201             foreach ($section as $sectionName) {
   202                 if (!isset(
$config[$sectionName])) {
   203                     #require_once 'Zend/Config/Exception.php';   205                         'Section "%s" cannot be found',
   206                         implode(
' ', (array)$section)
   212             parent::__construct($dataArray, $allowModifications);
   214             if (!isset(
$config[$section])) {
   215                 #require_once 'Zend/Config/Exception.php';   217                     'Section "%s" cannot be found',
   218                     implode(
' ', (array)$section)
   223             if (!is_array($dataArray)) {
   225                 $dataArray = array($section => $dataArray);
   227             parent::__construct($dataArray, $allowModifications);
   230         $this->_loadedSection = $section;
 setYamlDecoder($yamlDecoder)
 
elseif(isset( $params[ 'redirect_parent']))
 
call_user_func($callable, $param)
 
_processExtends(array $data, $section, array $config=array())
 
static setIgnoreConstants($flag)