Extensie:Variabelen

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This page is a translated version of the page Extension:Variables and the translation is 2% complete.

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MediaWiki uitbreidingshandleiding
OOjs UI icon advanced.svg
Variables
Release status: stabiel
Implementatie Parser function
Beschrijving Introduces parser functions for dealing with page-scoped variables.
Auteur(s)
Maintainer(s) MGChecker
Laatste versie 2.5.1 (2019-03-10)
MediaWiki 1.29+
PHP 5.5+
Database wijzigingen Nee
Licentie ISC License
Download
README
RELEASE-NOTES
Gebruikte hooks
ParserFirstCallInit
ParserClearState
InternalParseBeforeSanitize
Vertaal de Variables extensie indien beschikbaar op translatewiki.net
Bekijk gebruik en versiematrix
Vagrant rol variables
Problemen Open taken · Rapporteer een bug

The Variables extension allows you to define a variable on a page, use it later in that same page or included templates, change its value, possibly to a value given by an expression in terms of the old value, etc.

It is much like a template, only very lightweight and scoped to only a single page, so you can use many variables on a page without slowing down the wiki with huge numbers of templates. Combine this extension with the ParserFunctions extension for best results.

Assigning a value to a variable

#vardefine

  • {{#vardefine:variablename|specifiedvalue}}

Assigns the value specifiedvalue to the (already existing or hereby introduced) variable variablename.

  • Example: {{#vardefine:iconwidth|25}} making iconwidth = 25

#vardefineecho

  • {{#vardefineecho:variablename|specifiedvalue}}

Works exactly as #vardefine, but the affected value is printed.

  • Example: making iconwidth = <code>{{#vardefineecho:iconwidth|25}}</code>

Retrieving the value of a variable

#var

The value of the variable variablename is produced by

  • {{#var:variablename}}

If undefined, this produces an empty string; it does not give an error message.

It is possible to define a value for the case that the variable is undefined or void:

  • {{#var:variablename | defaultvalue }}

This is equivalent to:

  • {{#if: {{#var:variablename}} | {{#var:variablename }} | defaultvalue }}

but it is much shorter and better arranged. Before version 2.0 though, the default value always was expanded. From version 2.0 on the default only gets expanded in case it is actually used.

The value can be used in parser functions, etc.

#varexists

  • {{#varexists:variablename }} returns 1 if the variable is already defined. If the variable is not defined the return value is void.

It supports a second and a third parameter to replace these values.

  • {{#varexists: variablename | if-value | else-value }}

This is equivalent to:

  • {{#if: {{#varexists: variablename }} | if-value | else-value }}

but it is much shorter and better arranged. Before version 2.5 though, both were always expanded. From version 2.5 on the if and else values only get expanded when their cases are actually entered.

#var_final

Experimental new function introduced in Variables 2.0. This function will output the final, last value a variable has at the end of the page rendering. Naturally, the value will be inserted after the parser went over the entire wiki markup, so this function can't be used in other functions, expecting the right value is being used. Example:

  • {{#var_final:variablename | defaultvalue}}

The default value will be used if the variable doesn't exist at the final page rendering stage or if its value is an empty string. The default will be expanded right where the function is used, so the parameter will be expanded, even if it won't be needed.

Examples

The ParserFunctions extension must also be installed to use #expr.

Compute x = 2*a + b:

  • {{#vardefine:x|{{#expr:2*{{#var:a}}+{{#var:b}}}}}}

Add one to n:

  • {{#vardefine:n|{{#expr:{{#var:n}}+1}}}}

Installation

  • Download en plaats de bestanden in een map genaamd Variables in de extensions/ map.
  • Voeg de volgende code onderaan aan LocalSettings.php toe:
    wfLoadExtension( 'Variables' );
    
  • Yes Klaar – Navigeer naar Special:Version op de wiki om te controleren dat de uitbreiding succesvol is geïnstalleerd.

Voor gebruikers van MediaWiki 1.30 of lager:

De instructies hierboven beschrijven de nieuwe manier van het installeren van uitbreidingen, door middel van wfLoadExtension() Indien deze uitbreiding wordt geïnstalleerd op een eerdere versie (MediaWiki 1.30 en eerder), gebruik in plaats van wfLoadExtension( 'Variables' );:

require_once "$IP/extensions/Variables/Variables.php";

Compatibility

The recommended version of the Variables extension for recent MediaWiki releases is listed below. Older versions of the extensions might work as well, but aren't tested for new MediaWiki releases.

Note

This extension will not be enabled for wikis run by the Wikimedia Foundation (WMF). See phab:T9865, phab:T65324, phab:T113859, and phab:T151192.

See also