Help:Parser functions

A parser function is a special piece of code in MediaWiki which extends the template functionality to perform logical operations. When rendered, parser functions use the parameters included in the definition to print out a specific result.

Parser functions are written out the same way templates are, surrounded by curly brackets. They are most easily identified by having either a colon or a hash sign (#) in the function name (or both, as is in the case of the  function).

A list of all parser functions for use on a wiki is visible at Special:Version.

Step-by-step use
Below this step-by-step is extra information with links to help direct you to full-fledged documentation of each parser function. In this step-by-step guide, we will be using the  (if expression) parser function, which is enabled on each Community by default. Its syntax is:     In the example above, we filled in the mathematical expression (1 > 0), set the function to say "yes" if 1 > 0 is mathematically correct and say "no" if 1 > 0 is mathematically incorrect.   → . Note what would have happened if we had tweaked the expression but kept the returned values the same. The equation proves false because 0 is not greater than 1 and "no" is returned.   → .
 * 1) Identify the parser function that is appropriate for the task you are trying to do. There is a wide variety of parser functions, so be sure to do your research.
 * 1) Identify the proper syntax for the parser function you wish to use.
 * 1) Fill in the syntax.
 * 1) Save the page and verify that the function seems to be returning the expected value. In our example, "yes" should be returned because 1 is indeed greater than 0.

While the above example might seem silly, because one should always know 1 > 0, the power of the parser function is revealed when it is passed a parameter. Let's say you are designing an infobox for a wiki about a TV show. You want to include a character's age and determine if they are an adult or not.

If within the infobox you have, the code would say "This character is an adult" if the given age of the character is at or above 18. If the given age was less than 18, the code would instead say "This character is not an adult."

Built-in MediaWiki parser functions
The MediaWiki software itself includes multiple parser functions at the core. A full list of these are available here on MediaWiki.org. This page will illustrate the most useful.


 * Returns the full URL of a given page.
 * Returns the full URL of a given page.


 * Converts a language code to the language name.
 * Converts a language code to the language name.


 * Makes a string lowercase (opposite of ).
 * → case
 * → case


 * Takes a namespace number and tells you what the namespace is.
 * Takes a namespace number and tells you what the namespace is.


 * If a given expression equals one, returns the singular value given. If a given expression equals two, returns the plural value given.
 * → 1 is
 * → 2 iss
 * → 2 iss

ParserFunctions extension
The ParserFunctions extension is a popular MediaWiki extension that adds a number of useful parser functions on top of the MediaWiki ones listed above. This extension is enabled by default across all of Fandom, so you don't need to ask for it.

Parser functions can perform mathematical operations, evaluate if/else statements, and even manipulate time itself! (Well, the expression of time, anyway!)

To view a complete list of these functions and extremely useful documentation on how to use them, please visit the extension's official help page.

String functions
String functions are now a part of the ParserFunctions extension. But they used to be a part of their own, separate extension. So don't get confused when you read about it. Only the StringFunctions extension is deprecated. String functions themselves are alive and well!

String functions are a series of specialised parser functions that work on text strings. They allow you to do things like: On their own, string functions may seem arcane, but they're vital when you're trying to do something like turn Ant-Man (Earth-616) into just Ant-Man. They allow you to detect the parenthetical (Earth-616) and chop it off!
 * determine the length of a string
 * figure out which position in the string a particular character occupies
 * find a whole word in a string

Other extensions
Some other extensions that are popular on Fandom add their own parser functions. Two of the more common are Arrays and Variables.

To find out more about these, please consult that extension's page on MediaWiki.org.

Further help and feedback
de:Hilfe:ParserFunctions es:Ayuda:Funciones parser fr:Aide:Fonctions parseur it:Aiuto:Funzioni parser ja:ヘルプ:パーサー関数 ko:도움말:파서 함수 pl:Pomoc:Funkcje parsera pt:Ajuda:Funções parser ru:Справка:Синтаксический анализатор uk:Довідка:Синтаксичний аналізатор vi:Trợ giúp:Hàm phân tích cú pháp zh:Help:解析器函數