Extension:Subpage Fun

What can this extension do?
This extension provides your wiki with seven new parser functions/variables to get information about subpages which you can't get with MediaWikis existing magic Words. Also, this extension has a slightly different concept about what is considered a subpage than MediaWikis existing functions.

You can read almost everything you need to know about MediaWiki subpages here. This extension goes one step further and says a subpage is not simply the part behind a slash. A page only is a subpage in case a parent page exists. This means Subpage Fun wouldn't consider the page AC/DC a subpage as long as the page AC doesn't exist. Assuming the page AC/DC/Discography exists, the page AC/DC/Discography/1975/1976 would have the  1975/1976. The MediaWiki  variable would only output 1976 in this case which is nonsense since this page doesn't even exist.

For developers, this extension provides the php class  which can be helpful to gather information about subpages within other extensions.

Usage
Subpage Fun defines,  ,  ,  ,   and. You can use them either like that as variables for the current page or you can use them with a parameter like  to use them for any page you want.


 * SUBPAGETITLE: The real name of a subpage, not only the part behind the last slash like MediaWiki's SUBPAGENAME outputs it.
 * SUBPAGELEVEL: The subpage level of a page. A normal page which is no subpage at all would return.
 * NUMBEROFSUBPAGES: How many subpages does a page have. Also works with subpages to see how many subpages they have. Counts all descendant pages, not only direct child pages.
 * TOPLEVELPAGE: The top level page which is the page with subpage level  within the same subpage tree.
 * SUBPAGES: Outputs all Subpages as a comma separated list. This means all descendant pages, not only direct child pages. The output has no specific order.
 * PARENTPAGES: Outputs all ancestor pages as a comma separated list. The output begins with the top level page and ends with the direct parent page.
 * SIBLINGPAGES: Outputs all sibling pages of the same subpage level and tree as a comma separated list. The output has no specific order.

,,   have a list output. You can use this output for further use with Extension:Arrays for example.

If one function is used with parameter 1 on a page with invalid characters, the output value will be an empty string.

Advanced formatting
There are several more parameters for some functions beside 1 which is available for all functions and allows to define the page to get the information from.


 * linked: If this parameter has any value at all the pages in the list of list generating functions become links
 * sep: Allows to define a different list separator than the default separator
 * depth: Works with,   and  . It allows to define the relative depth to the most distant page. If the depth is set to a value smaller than 0 or not set, the functions will output everything, for   a negative value will return that many elements starting from the top-level page.
 * filter: Works with,  ,   and  . This parameter allows to define a regular expression (allowed delimiters  , allowed modifiers  ) which will filter all elements out of the list who don't match the expression. Alternatively, it is possible to define a simple word which must be part of a list entry or the entry won't be outputted. It is possible to define several words separated by an escaped   for example with help of a template like Template:! using.

 Examples: 


 * will output the currents page direct parent page as link.
 * will give the same result as  with the only difference that if   is the top-level page already, an empty string is returned.
 * will output all direct subpages below somepage seperated by a simple space.

Developers support
Developers can use some static php functions from the SubpageInfo class which delivers information about subpages which the MediaWiki Title class doesn't provide.

Download instructions
You can take the code from here. Create a new directory SubpageFun in your MediaWiki's extension directory and put the code in a new file SubpageFun.php there.

Installation
Once you have downloaded the code, place the SubpageFun directory within your MediaWiki extensions directory. Then add the following code near the bottom of your LocalSettings.php file:

Change Log
The full version history can be found within the RELEASE-NOTES.