/**
* Adds a child to the class at the given index
*
* @param AbstractPattern $child Child to add
* @param int $index Index
*
* @return AbstractContainer
*/
public function addChildAt(AbstractPattern $child, $index = null)
{
$child->setParent($this);
if ($index === null) {
$this->_children[] = $child;
} elseif (isset($this->_children[$index])) {
array_splice($this->_children, $index, 0, array($child));
} else {
$this->_children[$index] = $child;
ksort($this->_children);
}
return $this;
}
