Template:Ifsubst
 | This template is used in system messages, and on approximately 1,020,000 pages, or roughly 2% of all pages. Changes to it can cause immediate changes to the Wikipedia user interface. To avoid major disruption and server load, any changes should be tested in the template's /sandbox or /testcases subpages, or in your own user subpage. The tested changes can be added to this page in a single edit. Please discuss changes on the talk page before implementing them. |
Usage
Meta template that returns the first parameter if evaluated during substitution, and the second parameter if evaluated during transclusion.
Note that this template must be used in safesubst mode to work properly:
{{ safesubst:<noinclude/>ifsubst| yes | no }}
The |demo= parameter can be used for testing the template. Set |demo=yes to always display the yes text, |demo=no to always display the no text, or |demo={{{demo|}}} to pass through the value from the parent template.
List of subst helper templates
- {{require substitution}} – Prints an error unless substituted.
- {{ifsubst}} – if-then-else metatemplate that checks if a template is currently being substituted or transcluded.
- {{always substitute}} – For the doc of the above templates; prints a message asking for it be substituted.
- {{frequently substituted}} – Notice displayed in the documentation of substitution templates notifying the user that the template is widely used.
- {{never substitute}} – The reverse of {{always substitute}}. For the doc of templates which should not be substituted; prints a message asking for it not to be substituted.
- {{can be substituted}} – For the doc of templates whose substitution is optional.
- {{may be substituted}} – Same as the template above, but with the adverb may being used in the notice (instead of can).
- {{substitution}} – Allows free-fill description of whether the template should be substituted and under what conditions.
- {{issubst}} – Returns "yes" if substituted.
- {{HTML comment}} – To sign substitutions with comments that contain wikitext expansions.
- Module:Unsubst – Prevents substitution.
- Module:Unsubst-infobox – Prevents substitution for infoboxes, cleans up parameters.