Transclusion

Transclusion is generally the inclusion of the content of a document into another document by reference. In a wiki context, it is the use of the template functionality of MediaWiki to include the same content in multiple documents without having to edit those documents separately.

Etymology
Ted Nelson coined the term "transclusion", as well as "hypertext" and "hypermedia", in his 1982 book Literary Machines.

Partial transclusion
By using " noinclude ", " onlyinclude " and " includeonly " markup, it is possible to transclude part of a page rather than all of it. Such partial transclusions can also be achieved by transcluding from other pages such as subpages. It is often desirable not to transclude some information, such as template documentation and categories.

Examples of when to use full versus partial transclusion
Use full transclusion when you want to include the full content of a source page in a target page. For example, you could include the full content of a page about apples in a page about tree fruits. Use partial transclusion when you only want to include part of a source page in a target page. For example, you could include only information about Granny Smith apples from a page about apples in a page about ingredients commonly used in baking.

Partial transclusion markup

 * noinclude - The markup  means that the text between the tags is visible exclusively on the source page and cannot be transcluded onto another page. This is useful for template documentation and categories.
 * includeonly - The markup  means that the text between the tags will be hidden on the source page and visible only when transcluded onto a different page. This can be useful, for example, for adding categories to pages transcluding a template, without adding the template itself to these categories.
 * onlyinclude - The markup  means that the text between the tags will be visible on the source page and visible when transcluded onto a different page. This is the most subtle of the partial transclusion tags because it often overrules the others.  If there is at least one pair of " onlyinclude " tags on a page, then whenever this page is transcluded, it is only the material within the " onlyinclude " tags that is transcluded.  There can be several such " onlyinclude " sections on a page.    This can be useful, for example, to repeat a small part of one page on a second one: just surround the small part by onlyinclude tags, and transclude it onto the second page.

You can nest all three transclusion types within each other, which enables you to refine exactly what content is displayed on the current page and is visible on transcluded pages.

Special pages

 * See also:w:Wikipedia:Transclusion and 

Some pages on Special:Specialpages can be transcluded, such as Special:AllPages, Special:PrefixIndex, Special:NewFiles, Special:NewPages, Special:RecentChanges and Special:RecentChangesLinked.

Sample: gives 3 new pages.

URL parameters can be given like template parameters, e. g..

Alternatives to transclusion by template
Occasionally you may want to use a template, but for one reason or another may not want to use transclusion. The automatic one-time copying of a template's code/text to the location of a template tag is called Template substitution or subclusion (substitution + transclusion). To subclude a template's code/text, the template tag is modified from the standard transclusion tag to a substitution tag, simply by adding subst:, creating a tag with the form:.

Labeled Section Transclusion
An extension called Labeled Section Transclusion enables marked sections of text to be transcluded. An extension with a somewhat similar function is PageVariableExtension.

Semantic MediaWiki
The Semantic MediaWiki extension uses inline queries to query and display semantic data. There are currently two ways to perform transclusion or something similar: See inline queries for further information.
 * 1) Transclusion proper. The display format "embedded" ensures that selected pages (mainspace articles, templates, etc.) are transcluded. As with templates, sections placed between noinclude tags will be omitted.
 * 2) Selected passages in a page can be assigned a property of type 'Text'. These selections can be requested by running an inline query for this type of property.

Pages related to MediaWiki transclusion

 * w:Wikipedia:MediaWiki namespace
 * m:Help:MediaWiki namespace
 * m:Help:Variable
 * w:Wikipedia talk:Template namespace

Templates



 * w:Wikipedia:Template namespace
 * w:Wikipedia:Template limits