Category Traversal
==================

The CategoryTraverser class is used to start at one Category page in a wiki's category hierarchy
and descend through that category's children, grandchildren, and so on.
The basic output of this is a Pages object containing all the pages in the category tree.
It is also possible to register callbacks that will be called
for every subcategory or other page (i.e. anything not a category).

Basic usage
-----------

To get all pages in a category or any of its subcategories.

.. code-block:: php
   :linenos:

   // Construct the API.
   $api = new \Mediawiki\Api\MediawikiApi( 'http://localhost/w/api.php' );
   $services = new \Mediawiki\Api\MediawikiFactory( $api );
   $categoryTraverser = $services->newCategoryTraverser();

   // Get the root category.
   $rootCatIdent = new PageIdentifier( new Title( 'Category:Categories' ) );
   $rootCat = $this->factory->newPageGetter()->getFromPageIdentifier( $pageIdentifier );

   // Get all pages.
   $allPages = $categoryTraverser->descend( $rootCat );