The ParserFunctions extension provides ten additional parser functions to supplement the "magic words", which are already present in MediaWiki, eg. #if, #ifeq

Why needed:
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I realized I needed this extension when I was working on http://docs.moodle.org/en/Template:Infobox_Project. It is a template inspired by common infoboxes at wikipedia. But at the moment we are unable to do not display those rows from infobox table where the paramerer is missing. #if function provided by the extension is needed. See the attached URL for more information.