Template:If

The template {{If|subst=subst:}}

Based on http://meta.wikimedia.org/wiki/Template:If

[edit] Usage

• 4 parameters:
  • {{if||x| p | q }} gives " p "
  • {{if||| p | q }} gives " q "
  • {{if|expr|2<3| p | q }} gives " p "
  • {{if|expr|2>3| p | q }} gives " q "
  • {{if|expr|2{{=}}3| p | q }} gives " q "
  • {{if|expr||2=2=3| p | q }} gives " q "
  • {{if|exist| Template:If | p | q }} gives " p "
  • {{if|exist| No Such:If | p | q }} gives " q "
  • {{if|error|<span class{{=}}"error">x</span>| p | q }} gives " p "
  • {{if|error| 7 | p | q }} gives " q "
  • {{if|error| 7 | p | }} gives " "
  • {{if|error| 7 | p |}} gives ""
  • {{if|error| 7 | p }} gives " 7 "
• 5 parameters:
  • {{if|eq| u |u| p | q }} gives " p "
  • {{if|eq| u |v| p | q }} gives " q "

Compare:

• 3 parameters:
  • {{#if:x| p | q }} gives "p"
  • {{#ifexpr:2<3| p | q }} gives "p"
  • {{#ifexist: Help:Link | p | q }} gives "q"
  • {{#iferror:<span class="error">x</span>| p | q }} gives "p"
  • {{#iferror: 7 | p | q }} gives "q"
  • {{#iferror: 7 | p | }} gives ""
  • {{#iferror: 7 | p |}} gives ""
  • {{#iferror: 7 | p }} gives "7"
• 4 parameters:
  • {{#ifeq: u |u| p | q }} gives "p"

Note that, unlike parser functions, templates require writing equals signs in values of unnamed parameters as {{=}}

For full substitution, simply use Template:Cnw or Template:Cnw. If the condition contains a parser function, template, or variable, that should be substituted too. Optionally the "then" or "else" part can also be substituted.

Error messages (examples):

• {{if|expr|1234>e3|1|0}} gives Template:If: "#ifexpr:1234>e3" should give Expression error: Unexpected number but may not be evaluated due to the expansion depth limit.
• {{#ifexpr:1234>e3|1|0}} gives Expression error: Unexpected number