IF statements

The %IF% macro gives you the ability to test for macro values, URL parameters, access permissions, topic existence and more.

Syntax

%IF{"CONDITION" then="THEN" else="ELSE"}%

In the example above, if CONDITION evaluates to TRUE, then THEN will be included in the topic; otherwise ELSE will be included.

Note that because of the way Foswiki evaluates, whatever is in the THEN and ELSE parameters will already have been expanded by the time the condition is actually evaluated. The standard FormatTokens can be used in the THEN and ELSE parameters when you need to delay evaluation of (for example) a macro.

The basic syntax of a condition is the same as the syntax used for queries, with the addition of the following special operators:

The %IF% statement is deliberately kept simple. In particular, note that there is no way to conditionally execute a Set statement. If you need more sophisticated control over formatting, then consider using the SpreadSheetPlugin.

Macros

Test if macro is defined

%IF{"defined MACRO" then="THEN" else="ELSE"}%

Example:

%IF{
   "defined WIKINAME"
   then="WIKINAME is defined"
   else="WIKINAME is not defined"
}%

Compare macro definition

%IF{"$MACRO='VALUE'" then="THEN" else="ELSE"}%

Example:

You are %IF{
   "$WIKINAME='WikiGuest' and not defined 'OPEN_DAY'"
   then="not"
}% allowed to
%IF{
   "context view"
   then="view"
   else="edit"
}% this Foswiki today.

URL parameters

Test if URL param is passed

%IF{"defined PARAM" then="THEN" else="ELSE"}%

Example:

%IF{
   "defined search"
   then="Search:%URLPARAM{"search"}%"
   else="No search passed in"
}%

Note that macro URLPARAM is evaluated before the IF macro, therefore the expression does not need to be escaped.

Range test on URL parameter

%IF{"$PARAM < NUMBER" then="THEN" else="ELSE"}%

Example:

URL param t is %IF{
   "0 < $t and $t < 1000"
   then="in"
   else="out of"
}% range.

Text comparison of URL parameter

%IF{"$PARAM='VALUE'" then="THEN" else="ELSE"}%

or

%IF{"$'URLPARAM{PARAM}'='VALUE'" then="THEN" else="ELSE"}%

Example:

%IF{
   "$scope='text'"
   then="Plain text search"
}%

or

%IF{
   "$'URLPARAM{scope}'='text'"
   then="Plain text search"
}%

URL parameter test

Be careful when you test for an empty value: if the URL parameter is not defined (not passed in the URL), the outcome might not be what you expected. Use the parameter test to check your assumptions.

Reset test

INCLUDE parameters

%IF{"$PARAM" then="THEN" else="ELSE"}%

Parameters that are passed to the INCLUDE macro are evaluated the same as URL parameters. Combining those may lead to unexpected results!

Example:

%INCLUDE{"%TOPIC%" section="people" name="Barry"}%
%STARTSECTION{"people"}%
%IF{"$name" then="%name%"}%
%ENDSECTION{"people"}%

INCLUDE parameter test

%INCLUDE{"%TOPIC%" section="includetest" name="Barry"}%

%STARTSECTION{"includetest"}%
| *Test* \
| *IF query param 'name'* \
| *Result param 'name'* \
| *IF query param 'yo'* \
| *Result param 'yo'* |
| is defined \
| =defined name= \
| %IF{"defined name" then='true'}% \
| =defined yo= \
| %IF{"defined yo" else='false'}% |
| is empty \
| =$name=''= \
| %IF{"$name=''" else='false'}% \
| =$yo=''= \
| %IF{"$yo=''" else="false %RED%NOTE: value is undefined, so not empty%ENDCOLOR%"}% |
| is not empty \
| =$name!=''= \
| %IF{"$name!=''" then='true'}% \
| =$yo!=''= \
| %IF{"$yo=''" else="false %RED%NOTE: value is undefined, so not \'not empty\'%ENDCOLOR%"}% |
| has value =Barry= \
| =$name='Barry'= \
| %IF{"$name='Barry'" then='true'}% \
| =$yo='Barry'= \
| %IF{"$yo='Barry'" else='false'}% |
%ENDSECTION{"includetest"}%

Configuration values

Configuration items are defined in configure. You cannot see the value of a configuration item, you can only test if the item is set, or test the value against a string.

Items must be one of {AccessControlACL}{EnableDeprecatedEmptyDeny}, {AccessibleCFG}, {AdminUserLogin}, {AdminUserWikiName}, {AntiSpam}{EmailPadding}, {AntiSpam}{EntityEncode}, {AntiSpam}{HideUserDetails}, {AntiSpam}{RobotsAreWelcome}, {AttachmentNameFilter}, {AuthRealm}, {AuthScripts}, {Cache}{Enabled}, {DefaultDateFormat}, {DefaultUrlHost}, {DenyDotDotInclude}, {DisplayTimeValues}, {EnableEmail}, {EnableHierarchicalWebs}, {FormTypes}, {HomeTopicName}, {LeaseLength}, {LeaseLengthLessForceful}, {LinkProtocolPattern}, {LocalSitePreferences}, {LoginNameFilterIn}, {MaxRevisionsInADiff}, {MinPasswordLength}, {NameFilter}, {NotifyTopicName}, {NumberOfRevisions}, {PluginsOrder}, {Plugins}{WebSearchPath}, {PluralToSingular}, {Register}{AllowLoginName}, {Register}{Approvers}, {Register}{DisablePasswordConfirmation}, {Register}{EnableNewUserRegistration}, {Register}{NeedApproval}, {Register}{NeedVerification}, {Register}{RegistrationAgentWikiName}, {ReplaceIfEditedAgainWithin}, {SandboxWebName}, {ScriptSuffix}, {ScriptUrlPath}, {Site}{Locale}, {SitePrefsTopicName}, {Stats}{TopContrib}, {Stats}{TopicName}, {Stats}{TopViews}, {SuperAdminGroup}, {SystemWebName}, {TemplateLogin}{AllowLoginUsingEmailAddress}, {TemplatePath}, {TrashWebName}, {UploadFilter}, {UseLocale}, {UserInterfaceInternationalisation}, {UsersTopicName}, {UsersWebName}, {Validation}{Method}, {WebMasterEmail}, {WebMasterName}, {WebPrefsTopicName}.

Testing if item is set

%IF{"{CONFIGURATION}" then="THEN" else="ELSE"}%

Example:

User details are %IF{
   "{AntiSpam}{HideUserDetails}"
   then="hidden"
   else="shown"
}%

Testing the value of an item

%IF{"{CONFIGURATION}='VALUE'" then="THEN" else="ELSE"}%

Example:

Validation method is %IF{
   "{Validation}{Method}='strikeone'"
   then="'strikeone'"
   else="no 'strikeone'"
}%

Plugin states

%IF{"context PLUGINEnabled" then="THEN" else="ELSE"}%

Example:

TablePlugin is %IF{
   "context TablePluginEnabled"
   then="enabled"
   else="disabled"
}%.

Access permissions

%IF{"'SOME TOPIC' allows 'ACCESS'" then="THEN" else="ELSE"}%

Example:

You %IF{"'%TOPIC%' allows 'change'" then="can" else="cannot"}% change this topic.
You %IF{"'%SANDBOXWEB%.TestTopic' allows 'change'" then="can" else="cannot"}% change %SANDBOXWEB%.TestTopic.
You %IF{"'Sandbox' allows 'change'" then="can" else="cannot"}% change Sandbox web

Topic existence

%IF{"istopic 'SOME TOPIC'" then="THEN" else="ELSE"}%

Example:

Topic %SANDBOXWEB%.TestTopic %IF{"istopic '%SANDBOXWEB%.TestTopic'" then="exists" else="does not exist"}%.
Web %SANDBOXWEB% %IF{"isweb '%SANDBOXWEB%'" then="exists" else="does not exist"}%.

Group membership

To test if SOMEONE is in the GROUP:

%IF{"'SOMEONE' ingroup 'GROUP'" then="THEN" else="ELSE"}%

Or to test the currently logged in user for AdminGroup membership:

You are %IF{
   "$USERNAME ingroup 'AdminGroup'"
   then="an admin"
   else="a normal user"
}%

Context identifiers

%IF{"context CONTEXT" then="THEN" else="ELSE"}%

Context identifiers are used in Foswiki to label various stages of the rendering process. They are especially useful for skin authors to find out where they are in the rendering process. The following context identifiers are available:

In addition there is a context identifier for each enabled plugin; for example, if GallousBreeksPlugin is installed and enabled, then the context ID GallousBreeksPluginEnabled will be set. JQueryPlugin sets a context for each enabled JQuery plugin, for example: LiveQueryEnabled, UI::DialogEnabled. Other extensions may set additional context identifiers.

Query syntax

%IF{"QUERY" then="THEN" else="ELSE"}%

Examples

Display the value of a form field if the topic has form field "Summary":

%FORMFIELD{
   "%IF{
      "'%TOPIC%'/Summary"
      then="Summary"
   }%"
}%

Note that while a query search can be used to access form fields, there are some contexts in which an IF statement may be used where there is no topic context, or the topic context is not what you want. In these cases you can use the / operator to indicate the name of the topic:

The IF macro is expanded before FORMFIELD. Read more

Test if the topic has attachments:

%IF{
   "'%TOPIC%'/attachments"
   then="has attachments"
}%

Test if the topic has an attachment with 'receipt' or 'Receipt' in the name:

%IF{
   "'%TOPIC%'/attachments[lc(name)~'*receipt*']"
   then="has 'receipt' attachment"
}%

Test if a topic text contains a certain word:

%IF{
   "'%SYSTEMWEB%.%HOMETOPIC%'/lc(text)~'*welcome*'"
   then="contains 'welcome'"
}%