function book_export_traverse book_export_traverse($tree, $visit_func) Traverses the book tree to build printable or exportable output. During the traversal, the $visit_func() callback is applied to each node and is called recursively for each child of the node (in weight, title order). Parameters  $tree: A subtree of the book menu hierarchy, rooted at the current page. $visit_func: A function callback to be called upon visiting a node in the tree. Return value  The output generated in visiting each node. File
 modules/book/book.module, line 1240 Allows users to create and organize related content in an outline.  Code function book_export_traverse($tree, $visit_func) {
  $output = '';

  foreach ($tree as $data) {
    // Note- access checking is already performed when building the tree.
    if ($node = node_load($data['link']['nid'], FALSE)) {
      $children = '';

      if ($data['below']) {
        $children = book_export_traverse($data['below'], $visit_func);
      }

      if (function_exists($visit_func)) {
        $output .= call_user_func($visit_func, $node, $children);
      }
      else {
        // Use the default function.
        $output .= book_node_export($node, $children);
      }
    }
  }

  return $output;
}


    
{'path': 'public/docs/drupal~7/modules-book-book.module/function/book_export_traverse/7.x.html', 'source': 'DevDocs.IO'}