Extension:PreviewFunctions

What can this extension do?
This extension adds a function   With the intention people could issue warnings about template usage that only appear during preview. Its inspired by how Wikipedians abuse (see discussion on 100610). It also allows as an alias for #onpreview

Additionally it adds a tag hook  warning here  Which adds a warning to top of preview, in the same manner as how people are warned if they go over $wgExpensiveParserFunctionLimit on a page. It can also take a paramter nodiv to prevent the warning being contained inside a div (Aka  warning here ). If one wishes to have template parameters expanded, one must use syntax like  .

Download instructions
If you have an svn client installed, checkout the url http://svn.wikimedia.org/svnroot/mediawiki/trunk/extensions/PreviewFunctions Otherwise you may have to download the files individually by hand from that url.

(Note the version listed for 1.19 also works for version 1.18)

Installation
Download thingy, put it in appropriate place in extensions directory, add line  to bottom of LocalSettings.php

I have tested this extension with MediaWiki 1.18, so it should work on any version of MediaWiki 1.18 or higher. I don't use any particularly new features, so it will also probably work with earlier versions (if they aren't totally ancient), but i haven't tested that at all so ymmv.

Known limitations

 * previewwarning will strip out any strip markers when used in #tag mode. Hence one cannot use code like.