Editing Template:Error/doc

{{Documentation subpage}}
<!-- Place categories where indicated at the bottom of this page and interwikis at Wikidata (see [[Wikipedia:Wikidata]]) -->
{{high use}}
{{lua|Module:Error}}

This meta template returns a ''state of error'' (recognized as such by a wiki [[Help:Parser function|parser function]]), and optionally an ''error-message text'' in red (visible for the user). It is used by other templates to signal an error, for example invalid input, which can then either be displayed to the editor or caught and handled by other templates.

== Usage ==
* {{tlx|error|An exemplary error}} → {{error|An exemplary error}}
* {{tlx|error|message{{=}}An exemplary error}} → {{error|message=An exemplary error}}
* Compare, used in a Parser Function: <code><nowiki>{{#expr:Foo}}</nowiki></code> → {{#expr:Foo}}
* <code><nowiki>{{#iferror:{{error|Foo}} | {{y}} | {{n}} }}</nowiki></code> → {{#iferror:{{error|Foo}} | {{y}} | {{n}} }}

=== Tag option ===
The tag to contain the error message can be given through the <code>tag</code> parameter, but it will only accept <code>span</code>, <code>div</code>, <code>p</code>, and <code>strong</code>, since those are the only tags recognized by the {{pf|iferror}} parser function. It defaults to <code>strong</code>, the tag generated e.g. by {{pf|expr}}. To prevent <code>strong</code> message, use one of the other tags, e.g. <code>tag=span</code>.

* ABC {{tlx|error|An exemplary error demo no tag (default)}} XYZ → ABC {{error|An exemplary error demo no tag (default)}} XYZ
* ABC {{tlx|error|An exemplary error demo span|tag{{=}}span}} XYZ → ABC {{error|An exemplary error demo span|tag=span}} XYZ
* ABC {{tlx|error|An exemplary error demo div|tag{{=}}div}} XYZ → ABC {{error|An exemplary error demo div|tag=div}} XYZ
* ABC {{tlx|error|An exemplary error demo p|tag{{=}}p}} XYZ → ABC {{error|An exemplary error demo p|tag=p}} XYZ
* ABC {{tlx|error|An exemplary error demo strong|tag{{=}}strong}} XYZ → ABC {{error|An exemplary error demo strong|tag=strong}} XYZ

==TemplateData==
{{TemplateData header}}
<TemplateData>
{
	"description": "The template returns a state of error (recognized as such by a wiki parser function), and optionally an error-message text in red (visible for the user)",
	"params": {
		"1": {
			"label": "Message",
			"description": "Error message text in red",
			"type": "string",
			"required": false,
			"suggested": true,
			"aliases": [
				"message"
			]
		},
		"tag": {
			"label": "Tag",
			"description": "The tag to contain the error message; will only accept span, div, p, and strong, since those are the only tags recognized by the #iferror parser function. It defaults to strong, the tag generated e.g. by #expre",
			"type": "string",
			"default": "strong",
			"required": false,
			"suggestedvalues": [
				"span",
				"div",
				"p",
				"strong"
			]
		}
	}
}
</TemplateData>

==See also==
* {{tl|Error-small}}
* {{tl|Formatting error}}
* [[Help:Magic words#Conditional|#iferror: parser function]]

<includeonly>{{Sandbox other||
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[[Category:Wikipedia metatemplates]]
[[Category:Error-message templates]]
}}</includeonly>