context |
True if the current context is set (see below) |
allows |
'X' allows 'Y' is true if web/topic 'X' exists and allows access mode 'Y' for the current user. Web access rights are only checked if there is no topic called 'X'. |
istopic |
istopic 'X' is true if topic 'X' exists |
isweb |
isweb 'X' is true if web 'X' exists |
ingroup |
'X' ingroup 'Y' is true if user 'X' is in group 'Y'. 'X' can be a login name or a wikiname. |
defined |
True if a preference variable or url parameter of this name is defined. |
$ |
expands a URL parameter or [[Main/TWikiVariables]] name. Plugin handlers are not called. Built-in variables and user-defined preferences are supported. You can pass a limited subset of parameters to TWiki variables by enclosing the variable name in single quotes; for example, $ 'VARIABLE{value}' . The 'VARIABLE{value}' string may not contain quotes (' or "). |
{X} |
expands to the value of the configuration variable {X} - for example, {ScriptUrlPath} |
**_Examples:_**
1. TWiki variable defined or not
%IF{"defined 'WIKINAME'" then="WIKINAME is defined" else="WIKINAME is not defined"}%
2. Compare TWiki variable
You are %IF{ "$ WIKINAME='TWikiGuest' and not defined 'OPEN_DAY'" then="not" }% allowed to
%IF{ "context view" then="view" else="edit"}% this TWiki today.
3. URL parameter
%IF{ "defined 'search'" then="Search: $percntURLPARAM{search}$percnt" else="No search passed in"}%
4. Range test on URL parameter
url param t is %IF{ "0 < $ t and $ t < 1000" then="in" else="out of"}% range.
5. Text comparison of URL parameter
%IF{ "$'URLPARAM{scope}'='text'" then="Plain text search" }%
6. Configuration item set or not
%IF{ "{AntiSpam}{HideUserDetails}" then="User details are hidden" }%
7. Plugin enabled test
TablePlugin is %IF{ "context TablePluginEnabled" then="enabled" else="disabled" }%.
expands to: %BR% [[TablePlugin]] is enabled.
8. Check access permissions
You %IF{"'%TOPIC%' allows 'change'" then="can" else="cannot"}% change this topic.
You %IF{"'Sandbox.TestTopic' allows 'change'" then="can" else="cannot"}% change Sandbox.TestTopic.
You %IF{"'Sandbox' allows 'change'" then="can" else="cannot"}% change Sandbox web
expands to: %BR% You can change this topic. You can change [[TestTopic]]. You can change Sandbox web
9. Check topic existance
Topic Sandbox.TestTopic %IF{"istopic 'Sandbox.TestTopic'" then="exists" else="does not exist"}%
Web Sandbox.TestTopic %IF{"isweb 'Sandbox'" then="exists" else="does not exist"}%
expands to: %BR% Topic [[TestTopic]] exists Web [[TestTopic]] exists
10. Group membership
You %IF{"'%USERNAME%' ingroup 'TWikiAdminGroup'" then="are an admin" else="are a normal user"}%
expands to: %BR% You are an admin
**Configuration items** are defined in [configure](http://www.dementia.org/twiki/configure). You cannot see the value of a configuration item, you can only see if the item is set or not.
**Context identifiers** are used in TWiki to label various stages of the rendering process. They are especially useful for [[skin|Main/TWikiSkins]] authors to find out where they are in the rendering process. The following context identifiers are available:
id |
context |
absolute_urls |
Set if absolute URLs are required |
attach |
in attach script (see [[Main/TWikiScripts]]) |
authenticated |
a user is authenticated |
body_text |
when the body text is being processed in a view (useful in plugin handlers) |
can_login |
current environment supports login |
changes |
in changes script (see [[Main/TWikiScripts]]) |
command_line |
the running script was run from the command line, and not from CGI |
diff |
in rdiff script (see [[Main/TWikiScripts]]) |
edit |
in edit script (see [[Main/TWikiScripts]]) |
footer_text |
when the footer text is being processed in a view (useful in plugin handlers) |
header_text |
when the header text is being processed in a view (useful in plugin handlers) |
i18n_enabled |
when user interface I18N support is enabled (i.e., user can choose the language for UI) |
inactive |
if active links such as 'edit' and 'attach' should be disabled |
login & logon |
in login / logon script (see [[Main/TWikiScripts]]) |
manage |
in manage script (see [[Main/TWikiScripts]]) |
mirror |
if this is a mirror |
new_topic |
if the topic doesn't already exist |
oops |
in oops script (see [[Main/TWikiScripts]]) |
preview |
in preview script (see [[Main/TWikiScripts]]) |
register |
in register script (see [[Main/TWikiScripts]]) |
rename |
in rename script (see [[Main/TWikiScripts]]) |
resetpasswd |
in resetpasswd script (see [[Main/TWikiScripts]]) |
rss |
if this is an RSS skin rendering |
save |
in save script (see [[Main/TWikiScripts]]) |
search |
in search script (see [[Main/TWikiScripts]]) |
statistics |
in statistics script (see [[Main/TWikiScripts]]) |
textareas_hijacked |
provided for use by editors that highjack textareas, and want to signal this fact. This is used by skins, for example, so they can suppress extra controls when textareas have been hijacked. |
upload |
in upload script (see [[Main/TWikiScripts]]) |
view |
in view script (see [[Main/TWikiScripts]]) |
viewfile |
in viewfile script (see [[Main/TWikiScripts]]) |
rest |
in rest script (see [[Main/TWikiScripts]]) |
registration_supported |
registration is supported by the current [[Main/UserMapper]] |
registration_enabled |
set if {Register}{EnableNewUserRegistration} is on, and registrationis supported |
passwords_modifyable |
set if the password manager support changing the password / email |
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. Other extensions may set additional context identifiers.
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]].
Note also that while the [[query syntax|Main/QuerySearch]] 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 expected.