Editing Module:Unsubst/doc

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Maintenance templates, such as {{tl|Citation needed}} or {{tl|Refimprove}}, should never be substituted. A trick to avoid that is to make a template substitute to its transcluded form. This module implements that trick.

Infoboxes should use [[Module:Unsubst-infobox]], as should any other templates with parameters listed in block format by default.

=== Usage ===
To turn a template into a self-substituting template, wrap the existing template code with:
<pre>
{{safesubst:<noinclude />#invoke: Unsubst||$B=

 [ ... existing template code ... ]

}}
</pre>

The wikitext to display when not substed must be given as "$B". All other parameters passed to the #invoke will be copied to the generated template invocation as default values. If the value of any of these default parameters is <code>__DATE__</code>, that value in the generated template invocation will be the current month and year.

Some templates have a {{tag|noinclude|o}} but no matching {{tag|noinclude|c}} at the end of the template. In such cases the missing {{tag|noinclude|c}} must be added before the ending <code>{{))}}</code>.

==== Advanced ====

<pre>
{{safesubst:<noinclude />#invoke: Unsubst||$params=[ parameters ]|$aliases=[ aliases ]|$flags=[ flags ]|$B=

 [ ... existing template code ... ]

}}
</pre>

Due to Lua limitations, parameters are normally ordered randomly when the template is substituted. {{para|$params}} can be used in #invoke:Unsubst to list template parameters in order, comma-separated (e.g. <code>egg,bacon,sausage,cheese,spam</code>). Numbered parameters should be before others in the list. Any remaining parameters are tacked onto the end of the generated invocation.

Parameter aliases can be listed in {{para|$aliases}} (and shouldn't be listed in {{para|$params}}), and will be replaced automatically. Each alias and its replacement should be formatted as <code>alias>replacement</code>, and each of those pairs should be comma-separated (e.g. <code>œuf>egg,melt>cheese</code>). Note that this parameter can function with or without {{para|$params}}.

Parameter {{para|$flags}} can be used to modify other facets of the module's behaviour; entries are comma-separated. Valid flags are <code>override</code> (allows parameters in the #invoke: to take precedence over parameters in the original template invocation); <code>keep-whitespace</code> (prevents whitespace from being trimmed from unnamed parameters); and <code>remove-empty</code> (removes empty parameters).

These parameters can be manipulated using parser functions to provide more complicated options (note that in the parameters any parser function, or template or module invocation, should also have <code><nowiki>SAFESUBST:<noinclude /></nowiki></code>).

Parameter {{para|$template-name}} will override the subst'd template's name with the template name assigned to this parameter.

=== Example ===
Consider a template Template:Example containing the following code:
<pre>
{{safesubst:<noinclude />#invoke: Unsubst||foo=bar |date=__DATE__ |$B=

 [ ... Template code goes here ... ]

}}
</pre>

{| class="wikitable"
|-
! Original !! Result
|-
| {{tlsc|example}} || {{tlc|Example|date{{=}}{{#time:F Y}}|foo{{=}}bar}}
|-
| {{tlsc|example|foo{{=}}X}} || {{tlc|Example|date{{=}}{{#time:F Y}}|foo{{=}}X}}
|-
| {{tlsc|example|baz{{=}}X}} || {{tlc|Example|baz{{=}}X|date{{=}}{{#time:F Y}}|foo{{=}}bar}}
|-
| {{tlsc|example|date{{=}}January 2001}} || {{tlc|Example|date{{=}}January 2001|foo{{=}}bar}}
|}

<includeonly>{{sandbox other||
| <!-- Categories below this line, please; interwikis at Wikidata -->
[[Category:Wikipedia metatemplates]]
[[Category:Modules that add a tracking category]]
}}</includeonly>