Editing Module:If not given or empty/doc

This module's ''check_parameter'' function checks whether a parameter is given, empty, or nonempty in a template call.
It is intended to be called from template definitions only, as 
<syntaxhighlight lang="wikitext">{{#invoke:If not given or empty|check_parameter|parameter name|before|after|when=NG EM NE|notgiven=|empty=|notempty=}}</syntaxhighlight>
This is similar to {{tlx|If then show|<nowiki>{{{parameter name|}}}</nowiki>|...|before|after}}, but also checks if the parameter is *present* in the template call. This can be useful in the calls from a template to some existing templates, where the output depends on the three states of a parameter, as it does in {{tl|Location map}} for {{param|caption}}.

The values before and after are added only for cases in which {{para|when}} contains the codes NG (for not given), EM (given but empty), NE (given and not empty).

== Examples ==
Template {{tl|Infobox some thing}} has parameter {{param|image}}. When used on a page, the template can be called without the parameter, as in <code><nowiki>{{Infobox some thing|}}</nowiki></code>, or with the parameter, in which case the parameter can have no value (<code><nowiki>{{Infobox some thing|image=}}</nowiki></code>) or some value (<code><nowiki>{{Infobox some thing|image=some value}}</nowiki></code>). This module has different outputs depending on these three cases.

<code><nowiki>{{#invoke:If not given or empty|check_parameter|image|before | after|when=EM|notgiven=[[Image:Red pog.svg|30px]]|empty=EMPTY|notempty=[[File:{{{image}}}|30px]]}}</nowiki></code>

;<code><nowiki>{{Infobox some thing|}}</nowiki></code>: final output is the equivalent of <code><nowiki>[[Image:Red pog.svg|30px]]</nowiki></code>. Text <code><nowiki>before</nowiki></code> and <code><nowiki>after</nowiki></code> is not added because <code><nowiki>when</nowiki></code> does not contain NG (for ''not given'').

;<code><nowiki>{{Infobox some thing|image=}}</nowiki></code>: final output is <code><nowiki>before EMPTY after</nowiki></code>. Text <code><nowiki>before</nowiki></code> and <code><nowiki>after</nowiki></code> is added because <code><nowiki>when</nowiki></code> contains EM (for ''empty'').

;<code><nowiki>{{Infobox some thing|image=Green pog.svg}}</nowiki></code>: final output is the  equivalent of <code><nowiki>[[File:Green pog.svg|30px]]</nowiki></code>. Text <code><nowiki>before</nowiki></code> and <code><nowiki>after</nowiki></code> is not added because <code><nowiki>when</nowiki></code> does not contain NE (for ''not empty'').

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