Extension:CategoryHook.php

<?

1. CategoryHook Extension
2. - Adds a hook allowing articles to be added to additional categories based on wikitext content
3. - Version 0.1 (2007-04-18)
4. - See http://www.mediawiki.org/wiki/Extension:CategoryHook for installation and usage details
5. - Licenced under LGPL (http://www.gnu.org/copyleft/lesser.html)
6. - Author: http://www.organicdesign.co.nz/nad
7. {{#security:*|dev}}{{#security:view|*}}Template:Php

$wgExtensionCredits['parserhook'][] = array(

       'name'   => 'CategoryHook',
       'author' => 'User:Nad',
       'url'    => 'http://www.mediawiki.org/Extension:CategoryHook',
       );

1. Only process if action is submit, no changes to categories otherwise

if ($_REQUEST['action'] == 'submit') {

       $wgCategoryHookCatList = array();
       $wgHooks['ParserBeforeStrip'][] = 'wfCategoryHookProcess';
       $wgHooks['ParserAfterTidy'][]   = 'wfCategoryHookAdd';
       }

1. Determine the additional categories from the article's raw wikitext
2. - each item in the CatList is: catname => [ add(true) | del(false) , sortkey ]

function wfCategoryHookProcess(&$parser,&$text) {

       global $wgCategoryHookCatList,$wgTitle;
       $defaultSortKey = $wgTitle->getDBkey();

       # Articles containing trees
       $wgCategoryHookCatList['Articles_containing_trees']
               = array(preg_match('/\\{\\{#tree:/i',$text),$defaultSortKey);

       return true;
       }

1. Add the categories

function wfCategoryHookAdd(&$parser,&$text) {

       global $wgCategoryHookCatList;
       foreach ($wgCategoryHookCatList as $dbkey => $item) {
               list($add,$sortkey) = $item;
               if ($add) $parser->mOutput->addCategory($dbkey,$sortkey);
               else unset($parser->mOutput->mCategories[$dbkey]);
               }
       return true;
       }

?>