* Finally implemented a simple per-page data storage mechanism for plugins,

[ikiwiki.git] / doc / plugins / write.mdwn

diff --git a/doc/plugins/write.mdwn b/doc/plugins/write.mdwn
index 0e1839c6ca31157ddf0b5edcfd4d78529fbb2327..1cb26a076045ee7b99ac45a16327f4f12143b141 100644 (file)
--- a/doc/plugins/write.mdwn
+++ b/doc/plugins/write.mdwn
@@ -101,8 +101,8 @@ make arbitrary changes. The function is passed named parameters "page",
 
 ### preprocess
 
-Adding a [[PreProcessorDirective]] is probably the most common use of a
-plugin.
+Adding a [[ikiwiki/PreProcessorDirective]] is probably the most common use
+of a plugin.
 
         hook(type => "preprocess", id => "foo", call => \&preprocess);
 
@@ -126,11 +126,11 @@ the hook modifies data in `%links`. Note that doing so will make the hook
 be run twice per page build, so avoid doing it for expensive hooks.
 
 Note that if the [[htmlscrubber]] is enabled, html in
-[[PreProcessorDirective]] output is sanitised, which may limit what your
-plugin can do. Also, the rest of the page content is not in html format at
-preprocessor time. Text output by a preprocessor directive will be
-linkified and passed through markdown (or whatever engine is used to htmlize
-the page) along with the rest of the page.
+[[ikiwiki/PreProcessorDirective]] output is sanitised, which may limit what
+your plugin can do. Also, the rest of the page content is not in html
+format at preprocessor time. Text output by a preprocessor directive will
+be linkified and passed through markdown (or whatever engine is used to
+htmlize the page) along with the rest of the page.
 
 ### htmlize
 
@@ -164,7 +164,7 @@ a new custom parameter to the template.
 
        hook(type => "templatefile", id => "foo", call => \&templatefile);
 
-This hook allows plugins to change the [[template|wikitemplate]] that is
+This hook allows plugins to change the [[template|wikitemplates]] that is
 used for a page in the wiki. The hook is passed a "page" parameter, and
 should return the name of the template file to use, or undef if it doesn't
 want to change the default ("page.tmpl"). Template files are looked for in
@@ -313,6 +313,20 @@ A plugin can access the wiki's configuration via the `%config`
 hash. The best way to understand the contents of the hash is to look at
 [[ikiwiki.setup]], which sets the hash content to configure the wiki.
 
+### %pagestate
+
+The `%pagestate` hash can be used by plugins to save state that they will need
+next time ikiwiki is run. The hash holds per-page state, so to set a value,
+use `%pagestate{$page}{$id}{$key}=$value`, and to retrieve the value,
+use `%pagestate{$page}{$id}{$key}`.
+
+`$key` can be any string you like, but `$id` must be the same as the "id"
+parameter passed to `hook()` when registering the plugin. This is so
+ikiwiki can know when to delete pagestate for plugins that are no longer
+used.
+
+When pages are deleted, ikiwiki automatically deletes their pagestate too.
+
 ### Other variables
 
 If your plugin needs to access data about other pages in the wiki. It can
@@ -351,9 +365,10 @@ cleanup.
 
 Note that while any plugin can use this for a fatal error, plugins should
 try to avoid dying on bad input, as that will halt the entire wiki build
-and make the wiki unusable. So for example, if a [[PreProcessorDirective]]
-is passed bad parameters, it's better to return an error message, which can
-appear on the wiki page, rather than calling error().
+and make the wiki unusable. So for example, if a
+[[ikiwiki/PreProcessorDirective]] is passed bad parameters, it's better to
+return an error message, which can appear on the wiki page, rather than
+calling error().
 
 #### `template($;@)`
 
@@ -368,12 +383,12 @@ page created from it. (Ie, it appends ".html".)
 
 #### `add_depends($$)`
 
-Makes the specified page depend on the specified [[PageSpec]].
+Makes the specified page depend on the specified [[ikiwiki/PageSpec]].
 
 #### `pagespec_match($$;@)`
 
-Passed a page name, and [[PageSpec]], returns true if the [[PageSpec]]
-matches the page.
+Passed a page name, and [[ikiwiki/PageSpec]], returns true if the
+[[ikiwiki/PageSpec]] matches the page.
 
 Additional named parameters can be passed, to further limit the match.
 The most often used is "location", which specifies the location the
@@ -386,7 +401,7 @@ Given a page and the text of a link on the page, determine which
 existing page that link best points to. Prefers pages under a
 subdirectory with the same name as the source page, failing that
 goes down the directory tree to the base looking for matching
-pages, as described in [[SubPage/LinkingRules]].
+pages, as described in [[ikiwiki/SubPage/LinkingRules]].
 
 #### `htmllink($$$;@)`
 
@@ -477,10 +492,13 @@ search for files.
 If the directory name is not absolute, ikiwiki will assume it is in
 the parent directory of the configured underlaydir.
 
-#### `displaytime($)`
+#### `displaytime($;$)`
 
 Given a time, formats it for display.
 
+The optional second parameter is a strftime format to use to format the
+time.
+
 #### `gettext`
 
 This is the standard gettext function, although slightly optimised.
@@ -511,9 +529,9 @@ See [[RCS_details|rcs/details]] for some more info.
 ## PageSpec plugins
 
 It's also possible to write plugins that add new functions to
-[[PageSpecs|PageSpec]]. Such a plugin should add a function to the
+[[PageSpecs|ikiwiki/PageSpec]]. Such a plugin should add a function to the
 IkiWiki::PageSpec package, that is named `match_foo`, where "foo()" is
-how it will be accessed in a [[PageSpec]]. The function will be passed
+how it will be accessed in a [[ikiwiki/PageSpec]]. The function will be passed
 two parameters: The name of the page being matched, and the thing to match
 against. It may also be passed additional, named parameters. It should return
 a IkiWiki::SuccessReason object if the match succeeds, or an