View source for Template:Ifdef/doc

{{Documentation subpage}}
This template provides branching without [[mw:Help:Extension:ParserFunctions|Extension:ParserFunctions]] for simple 
"'''if''' ''defined'' '''then''' ''do''" statements
without '''else''' part. It is the opposite of [[Template:Ifndef]].

See [[Template:Ifwpc]] for an overview of results, and comparisons.

== Usage ==

<code>{&#123;ifdef|value|result&#125;}</code>
yields ''result''&#160; if ''value''&#160; isn't blank.

It uses the code <code><nowiki>{{{1{{{1</nowiki>'''|'''}}}'''|'''<nowiki>{{{2|}}}}}}</nowiki></code>.

== Examples ==
<!-- for the documentation don't subst the result -->
{| class="wikitable"
! Code
! Result
|-
| <code><nowiki>{{ifdef|x|y}}</nowiki></code>
| {{ifdef|x|y}}
|-
| <code><nowiki>{{ifdef||y}}</nowiki></code>
| {{ifdef||y}}
|-
| <code><nowiki>{{ifdef|2=y}}</nowiki></code>
| {{ifdef|2=y}}
|-
| <code><nowiki>{{ifdef|x}}</nowiki></code>
| {{ifdef|x}}
|-
| <code><nowiki>{{ifdef|}}</nowiki></code>
| {{ifdef|}}
|-
| <code><nowiki>{{ifdef}}</nowiki></code>
| {{ifdef}}
|}

== Substitution ==
Convenient of the parameter default mechanism is that substitution works also, without any extra code.