from WikkaWiki: 
http://wikkawiki.org/.
it works in WackoWiki in my site: http://www.openstory.ru
{{category}}
/actions/category.php
<?php
if ($cattag = $_REQUEST["wakka"])
{
$str ="";
if (!isset($col)) $col=1;
if (!isset($compact)) $compact=0;
if (!isset($page)) $page=$this->getPageTag();
if ($page=="/") $page="CategoryCategory";
// $page= preg_replace( "/(\w+)\s(\w+)/", "$1$2",$page);
if (isset($class)) {
$class="class=\"$class\"";
} else {
$class="";
}
if (!$page) {$page=$cattag;}
if ($this->CheckMySQLVersion(4,0,1))
{
$results = $this->FullCategoryTextSearch($page);
}
else
{
$results = $this->FullTextSearch($page);
}
if ($results)
{
if (!$compact) $str .= ' pages belong to ' . $page . ': <br /><br /><table '.$class.' width="100%"><tr>';
else $str .= '<div '.$class.'><ul>';
$count = 0;
$pagecount = 0;
$list = array();
foreach ($results as $i => $cpage) if($cpage['tag'] != $page) { array_push($list,$cpage['tag']);}
sort($list);
while (list($key, $val) = each($list)) {
if ($count == $col & !$compact) { $str .= "</tr><tr>"; $count=0; }
if (!$compact) $str .= '<td>'.$this->Format('[['.$val.']]').'</td>';
else $str .= '<li>'.$this->Format('[['.$val.' '.preg_replace( "/Category/", "",$val).']]').'</li>';
$count++;
$pagecount++;
}
$str = 'The following '.$pagecount.$str;
if (!$compact) $str .= '</tr></table>'; else $str .= '</ul></div>';
}
else $str .= 'Sorry, no items found for ' . $page .'.';
print($str);
}
?>
include this to classes/wacko.php
<?php
function CheckMySQLVersion($major, $minor, $subminor)
{
$result = @mysql_query('SELECT VERSION() AS version');
if ($result != FALSE && @mysql_num_rows($result) > 0)
{
$row = mysql_fetch_array($result);
$match = explode('.', $row['version']);
}
else
{
$result = @mysql_query('SHOW VARIABLES LIKE \'version\'');
if ($result != FALSE && @mysql_num_rows($result) > 0) {
$row = mysql_fetch_row($result);
$match = explode('.', $row[1]);
} else {
return 0;
}
}
$mysql_major = $match[0];
$mysql_minor = $match[1];
$mysql_subminor = $match[2][0].$match[2][1];
if ($mysql_major > $major) {
return 1;
} else {
if (($mysql_major == $major) && ($mysql_minor >= $minor) && ($mysql_subminor >= $subminor)) {
return 1;
} else {
return 0;
}
}
}
function ExistsPage($page)
{
$count = 0;
$query = "SELECT COUNT(tag)
FROM ".$this->config['table_prefix']."pages
WHERE tag='".mysql_real_escape_string($page)."'";
if ($r = $this->Query($query))
{
$count = mysql_result($r,0);
mysql_free_result($r);
}
return ($count > 0) ? TRUE : FALSE;
}
function getCatMembers($category)
{
if ($this->CheckMySQLVersion(4,0,1))
{
return $this->FullCategoryTextSearch($category);
}
else
{
return $this->FullTextSearch($category); # @@@ could be more efficient by returning only 'tag'
}
}
function FullCategoryTextSearch($phrase) { return $this->LoadAll("select * from ".$this->config["table_prefix"]."pages where latest = 'Y' and match(body) against('".mysql_real_escape_string($phrase)."' IN BOOLEAN MODE)"); }
?>
to use it you mast create page CategoryCaregory – it will be Main Category – Index of Categories and include there {{category}}
All next categories must be named like CategorySomeName and have action {{category}} and link to ((CategoryCategory List of all Categories)).
If you want to insert you page to some Category, you mast put there link CategoryName_of_Category
