title_natural patch merged

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

diff --git a/doc/plugins/write.mdwn b/doc/plugins/write.mdwn
index 7c28088ded55f9fce9b9012e9c31f9e72814145e..696bc6bc37bb910af72e256b90d2250159965c7e 100644 (file)
--- a/doc/plugins/write.mdwn
+++ b/doc/plugins/write.mdwn
@@ -19,7 +19,7 @@ that can be fleshed out to make a useful plugin.
 `IkiWiki::Plugin::pagecount` is another simple example. All perl plugins
 should `use IkiWiki` to import the ikiwiki plugin interface. It's a good
 idea to include the version number of the plugin interface that your plugin
 `IkiWiki::Plugin::pagecount` is another simple example. All perl plugins
 should `use IkiWiki` to import the ikiwiki plugin interface. It's a good
 idea to include the version number of the plugin interface that your plugin

-expects: `use IkiWiki 2.00`.
+expects: `use IkiWiki 3.00`.

 
 An external plugin is an executable program. It can be written in any
 language. Its interface to ikiwiki is via XML RPC, which it reads from
 
 An external plugin is an executable program. It can be written in any
 language. Its interface to ikiwiki is via XML RPC, which it reads from


@@ -55,8 +55,8 @@ plugin, and a "call" parameter, which tells what function to call for the
 hook.
 
 An optional "last" parameter, if set to a true value, makes the hook run
 hook.
 
 An optional "last" parameter, if set to a true value, makes the hook run

-after all other hooks of its type. Useful if the hook depends on some other
-hook being run first.
+after all other hooks of its type, and an optional "first" parameter makes
+it run first. Useful if the hook depends on some other hook being run first.

 
 ## Types of hooks
 
 
 ## Types of hooks
 


@@ -107,7 +107,7 @@ adding or removing files from it.
 
 This hook is called early in the process of building the wiki, and is used
 as a first pass scan of the page, to collect metadata about the page. It's
 
 This hook is called early in the process of building the wiki, and is used
 as a first pass scan of the page, to collect metadata about the page. It's

-mostly used to scan the page for WikiLinks, and add them to `%links`.
+mostly used to scan the page for [[WikiLinks|ikiwiki/WikiLink]], and add them to `%links`.

 Present in IkiWiki 2.40 and later.
 
 The function is passed named parameters "page" and "content". Its return
 Present in IkiWiki 2.40 and later.
 
 The function is passed named parameters "page" and "content". Its return


@@ -123,34 +123,42 @@ make arbitrary changes. The function is passed named parameters "page",
 
 ### preprocess
 
 
 ### preprocess
 

-Adding a [[ikiwiki/PreProcessorDirective]] is probably the most common use
+Adding a preprocessor [[ikiwiki/directive]] is probably the most common use

 of a plugin.
 
         hook(type => "preprocess", id => "foo", call => \&preprocess);
 
 of a plugin.
 
         hook(type => "preprocess", id => "foo", call => \&preprocess);
 

-Replace "foo" with the command name that will be used inside brackets for
-the preprocessor directive.
-
-Each time the directive is processed, the referenced function (`preprocess`
-in the example above) is called, and is passed named parameters. A "page"
-parameter gives the name of the page that embedded the preprocessor
-directive, while a "destpage" parameter gives the name of the page the
-content is going to (different for inlined pages), and a "preview"
-parameter is set to a true value if the page is being previewed. All
-parameters included in the directive are included as named parameters as
-well. Whatever the function returns goes onto the page in place of the
+Replace "foo" with the command name that will be used for the preprocessor

 directive.
 
 directive.
 

-An optional "scan" parameter, if set to a true value, makes the hook be
-called during the preliminary scan that ikiwiki makes of updated pages,
-before begining to render pages. This parameter should be set to true if
-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. (As an
-optimisation, if your preprocessor hook is called in a void contets, you
-can assume it's being run in scan mode.)
+Each time the directive is processed, the referenced function (`preprocess`
+in the example above) is called. Whatever the function returns goes onto
+the page in place of the directive. Or, if the function aborts using
+`error()`, the directive will be replaced with the error message.
+
+The function is passed named parameters. First come the parameters set
+in the preprocessor directive. These are passed in the same order as
+they're in the directive, and if the preprocessor directive contains a bare
+parameter (example: `\[[!foo param]]`), that parameter will be passed with
+an empty value.
+
+After the parameters from the preprocessor directive some additional ones
+are passed: A "page" parameter gives the name of the page that embedded the
+preprocessor directive, while a "destpage" parameter gives the name of the
+page the content is going to (different for inlined pages), and a "preview"
+parameter is set to a true value if the page is being previewed.
+
+If `hook` is passed an optional "scan" parameter, set to a true value, this
+makes the hook be called during the preliminary scan that ikiwiki makes of
+updated pages, before begining to render pages. This should be done if 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. (As an
+optimisation, if your preprocessor hook is called in a void context, you
+can assume it's being run in scan mode, and avoid doing expensive things at
+that point.)

 
 Note that if the [[htmlscrubber]] is enabled, html in
 
 Note that if the [[htmlscrubber]] is enabled, html in

-[[ikiwiki/PreProcessorDirective]] output is sanitised, which may limit what
+preprocessor [[ikiwiki/directive]] 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
 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


@@ -160,7 +168,7 @@ htmlize the page) along with the rest of the page.
 
        hook(type => "linkify", id => "foo", call => \&linkify);
 
 
        hook(type => "linkify", id => "foo", call => \&linkify);
 

-This hook is called to convert [[WikiLinks|WikiLink]] on the page into html
+This hook is called to convert [[WikiLinks|ikiwiki/WikiLink]] on the page into html

 links. The function is passed named parameters "page", "destpage", and
 "content". It should return the linkified content.  Present in IkiWiki 2.40
 and later.
 links. The function is passed named parameters "page", "destpage", and
 "content". It should return the linkified content.  Present in IkiWiki 2.40
 and later.


@@ -180,6 +188,15 @@ languages to ikiwiki.
 The function is passed named parameters: "page" and "content" and should
 return the htmlized content.
 
 The function is passed named parameters: "page" and "content" and should
 return the htmlized content.
 

+If `hook` is passed an optional "keepextension" parameter, set to a true
+value, then the extension will not be stripped from the source filename when
+generating the page.
+
+If `hook` is passed an optional "noextension" parameter, set to a true
+value, then the id parameter specifies not a filename extension, but
+a whole filename that can be htmlized. This is useful for files
+like `Makefile` that have no extension.
+

 ### pagetemplate
 
        hook(type => "pagetemplate", id => "foo", call => \&pagetemplate);
 ### pagetemplate
 
        hook(type => "pagetemplate", id => "foo", call => \&pagetemplate);


@@ -291,7 +308,7 @@ can check if the session object has a "name" parameter set.
 
 ### canedit
 
 
 ### canedit
 

-       hook(type => "canedit", id => "foo", call => \&pagelocked);
+       hook(type => "canedit", id => "foo", call => \&canedit);

 
 This hook can be used to implement arbitrary access methods to control when
 a page can be edited using the web interface (commits from revision control
 
 This hook can be used to implement arbitrary access methods to control when
 a page can be edited using the web interface (commits from revision control


@@ -309,6 +326,26 @@ This hook should avoid directly redirecting the user to a signin page,
 since it's sometimes used to test to see which pages in a set of pages a
 user can edit.
 
 since it's sometimes used to test to see which pages in a set of pages a
 user can edit.
 

+### checkcontent
+       
+       hook(type => "checkcontent", id => "foo", call => \&checkcontent);
+
+This hook is called to check the content a user has entered on a page,
+before it is saved, and decide if it should be allowed.
+
+It is passed named parameters: `content`, `page`, `cgi`, and `session`. If
+the content the user has entered is a comment, it may also be passed some
+additional parameters: `author`, `url`, and `subject`. The `subject`
+parameter may also be filled with the user's comment about the change.
+
+Note: When the user edits an existing wiki page, the passed `content` will
+include only the lines that they added to the page, or modified.
+
+The hook should return `undef` on success. If the content is disallowed, it
+should return a message stating what the problem is, or a function
+that can be run to perform whatever action is necessary to allow the user
+to post the content.
+

 ### editcontent
 
        hook(type => "editcontent", id => "foo", call => \&editcontent);
 ### editcontent
 
        hook(type => "editcontent", id => "foo", call => \&editcontent);


@@ -348,7 +385,7 @@ This hook is called whenever ikiwiki normally saves its state, just before
 the state is saved. The function can save other state, modify values before
 they're saved, etc.
 
 the state is saved. The function can save other state, modify values before
 they're saved, etc.
 

-## renamepage
+### renamepage

 
        hook(type => "renamepage", id => "foo", call => \&renamepage);
 
 
        hook(type => "renamepage", id => "foo", call => \&renamepage);
 


@@ -357,11 +394,69 @@ something. The hook is passed named parameters: `page`, `oldpage`,
 `newpage`, and `content`, and should try to modify the content to reflect
 the name change. For example, by converting links to point to the new page.
 
 `newpage`, and `content`, and should try to modify the content to reflect
 the name change. For example, by converting links to point to the new page.
 

+### getsetup
+
+       hook(type => "getsetup", id => "foo", call => \&getsetup);
+
+This hooks is not called during normal operation, but only when setting up 
+the wiki, or generating a setup file. Plugins can use this hook to add
+configuration options.
+
+The hook is passed no parameters. It returns data about the configuration
+options added by the plugin. It can also check if the plugin is usable, and
+die if not, which will cause the plugin to not be offered in the configuration
+interface.
+
+The data returned is a list of `%config` options, followed by a hash
+describing the option. There can also be an item named "plugin", which
+describes the plugin as a whole. For example:
+
+                return
+                       option_foo => {
+                               type => "boolean",
+                               description => "enable foo?",
+                               advanced => 1,
+                               safe => 1,
+                               rebuild => 1,
+                       },
+                       option_bar => {
+                               type => "string",
+                               example => "hello",
+                               description => "option bar",
+                               safe => 1,
+                               rebuild => 0,
+                       },
+                       plugin => {
+                               description => "description of this plugin",
+                               safe => 1,
+                               rebuild => 1,
+                       },
+
+* `type` can be "boolean", "string", "integer", "pagespec",
+  or "internal" (used for values that are not user-visible). The type is
+  the type of the leaf values;  the `%config` option may be an array or
+  hash of these.
+* `example` can be set to an example value.
+* `description` is a short description of the option.
+* `link` is a link to further information about the option. This can either
+  be a [[ikiwiki/WikiLink]], or an url.
+* `advanced` can be set to true if the option is more suitable for advanced
+  users.
+* `safe` should be false if the option should not be displayed in unsafe
+  configuration methods, such as the web interface. Anything that specifies
+  a command to run, a path on disk, or a regexp should be marked as unsafe.
+  If a plugin is marked as unsafe, that prevents it from being
+  enabled/disabled.
+* `rebuild` should be true if changing the option (or enabling/disabling
+  the plugin) will require a wiki rebuild, false if no rebuild is needed,
+  and undef if a rebuild could be needed in some circumstances, but is not
+  strictly required.
+

 ## Plugin interface
 
 To import the ikiwiki plugin interface:
 
 ## Plugin interface
 
 To import the ikiwiki plugin interface:
 

-       use IkiWiki '2.00';
+       use IkiWiki '3.00';

 
 This will import several variables and functions into your plugin's
 namespace. These variables and functions are the ones most plugins need,
 
 This will import several variables and functions into your plugin's
 namespace. These variables and functions are the ones most plugins need,


@@ -376,14 +471,14 @@ it's not exported, the wise choice is to not use it.
 
 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
 
 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.
+your ikiwiki setup file, 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,
 
 ### %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}{$key}`.
+use `$pagestate{$page}{$id}{$key}=$value`, and to retrieve the value,
+use `$pagestate{$page}{$id}{$key}`.

 
 The `$value` can be anything that perl's Storable module is capable of
 serializing. `$key` can be any string you like, but `$id` must be the same
 
 The `$value` can be anything that perl's Storable module is capable of
 serializing. `$key` can be any string you like, but `$id` must be the same


@@ -396,6 +491,15 @@ When pages are deleted, ikiwiki automatically deletes their pagestate too.
 Note that page state does not persist across wiki rebuilds, only across
 wiki updates.
 
 Note that page state does not persist across wiki rebuilds, only across
 wiki updates.
 

+### %wikistate
+
+The `%wikistate` hash can be used by a plugin to store persistant state
+that is not bound to any one page. To set a value, use
+`$wikistate{$id}{$key}=$value, where `$value` is anything Storable can
+serialize, `$key` is any string you like, and `$id` must be the same as the
+"id" parameter passed to `hook()` when registering the plugin, so that the
+state can be dropped if the plugin is no longer used.
+

 ### Other variables
 
 If your plugin needs to access data about other pages in the wiki. It can
 ### Other variables
 
 If your plugin needs to access data about other pages in the wiki. It can


@@ -407,7 +511,7 @@ use the following hashes, using a page name as the key:
   destination file.
 * `%pagesources` contains the name of the source file for each page.
 
   destination file.
 * `%pagesources` contains the name of the source file for each page.
 

-Also, the %IkiWiki::version variable contains the version number for the
+Also, the `%IkiWiki::version` variable contains the version number for the

 ikiwiki program.
 
 ### Library functions
 ikiwiki program.
 
 ### Library functions


@@ -433,7 +537,7 @@ function that is called after the error message is printed, to do any final
 cleanup.
 
 If called inside a preprocess hook, error() does not abort the entire
 cleanup.
 
 If called inside a preprocess hook, error() does not abort the entire

-wiki build, but instead replaces the [[ikiwiki/PreProcessorDirective]] with
+wiki build, but instead replaces the preprocessor [[ikiwiki/directive]] with

 a version containing the error message.
 
 In other hooks, error() is a fatal error, so use with care. Try to avoid
 a version containing the error message.
 
 In other hooks, error() is a fatal error, so use with care. Try to avoid


@@ -451,6 +555,9 @@ parameters are passed to `HTML::Template->new`.
 Passed a page name, returns the base name that will be used for a the html
 page created from it. (Ie, it appends ".html".)
 
 Passed a page name, returns the base name that will be used for a the html
 page created from it. (Ie, it appends ".html".)
 

+Use this when constructing the filename of a html file. Use `urlto` when
+generating a link to a page.
+

 #### `add_depends($$)`
 
 Makes the specified page depend on the specified [[ikiwiki/PageSpec]].
 #### `add_depends($$)`
 
 Makes the specified page depend on the specified [[ikiwiki/PageSpec]].


@@ -527,6 +634,16 @@ A failure to write the file will result in it dying with an error.
 
 If the destination directory doesn't exist, it will first be created.
 
 
 If the destination directory doesn't exist, it will first be created.
 

+The filename and directory are separate parameters because of
+some security checks done to avoid symlink attacks. Before writing a file,
+it checks to make sure there's not a symlink with its name, to avoid
+following the symlink. If the filename parameter includes a subdirectory
+to put the file in, it also checks if that subdirectory is a symlink, etc.
+The directory parameter, however, is not checked for symlinks. So,
+generally the directory parameter is a trusted toplevel directory like
+the srcdir or destdir, and any subdirectories of this are included in the
+filename parameter.
+

 #### `will_render($$)`
 
 Given a page name and a destination file name (not including the base
 #### `will_render($$)`
 
 Given a page name and a destination file name (not including the base


@@ -553,6 +670,23 @@ a type that ikiwiki knowns how to htmlize. Otherwise, returns undef.
 Given the name of a source file, returns the name of the wiki page
 that corresponds to that file.
 
 Given the name of a source file, returns the name of the wiki page
 that corresponds to that file.
 

+#### `pagetitle($)`
+
+Give the name of a wiki page, returns a version suitable to be displayed as
+the page's title. This is accomplished by de-escaping escaped characters in
+the page name. "_" is replaced with a space, and '__NN__' is replaced by 
+the UTF character with code NN.
+
+#### `titlepage($)`
+
+This performs the inverse of `pagetitle`, ie, it converts a page title into
+a wiki page name.
+
+#### `linkpage($)`
+
+This converts text that could have been entered by the user as a
+[[ikiwiki/WikiLink]] into a wiki page name.
+

 #### `srcfile($;$)`
 
 Given the name of a source file in the wiki, searches for the file in
 #### `srcfile($;$)`
 
 Given the name of a source file in the wiki, searches for the file in


@@ -591,11 +725,21 @@ destination file, as registered by `will_render`.
 If the third parameter is passed and is true, an absolute url will be
 constructed instead of the default relative url.
 
 If the third parameter is passed and is true, an absolute url will be
 constructed instead of the default relative url.
 

-#### `targetpage($$)`
+#### `newpagefile($$)`
+
+This can be called when creating a new page, to determine what filename
+to save the page to. It's passed a page name, and its type, and returns
+the name of the file to create, relative to the srcdir.
+
+#### `targetpage($$;$)`

 
 Passed a page and an extension, returns the filename that page will be
 rendered to.
 
 
 Passed a page and an extension, returns the filename that page will be
 rendered to.
 

+Optionally, a third parameter can be passed, to specify the preferred
+filename of the page. For example, `targetpage("foo", "rss", "feed")`
+will yield something like `foo/feed.rss`.
+

 ## Miscellaneous
 
 ### Internal use pages
 ## Miscellaneous
 
 ### Internal use pages


@@ -606,22 +750,138 @@ are collected together to form the RecentChanges page, for example.
 
 To make an internal use page, register a filename extension that starts
 with "_". Internal use pages cannot be edited with the web interface,
 
 To make an internal use page, register a filename extension that starts
 with "_". Internal use pages cannot be edited with the web interface,

-generally shouldn't contain wikilinks or preprocessor directives (use
+generally shouldn't contain [[WikiLinks|ikiwiki/WikiLink]] or preprocessor directives (use

 either on them with extreme caution), and are not matched by regular
 PageSpecs glob patterns, but instead only by a special `internal()`
 [[ikiwiki/PageSpec]].
 
 ### RCS plugins
 
 either on them with extreme caution), and are not matched by regular
 PageSpecs glob patterns, but instead only by a special `internal()`
 [[ikiwiki/PageSpec]].
 
 ### RCS plugins
 

-ikiwiki's support for [[revision_control_systems|rcs]] also uses pluggable
-perl modules. These are in the `IkiWiki::RCS` namespace, for example
-`IkiWiki::RCS::svn`. 
+ikiwiki's support for [[revision_control_systems|rcs]] is also done via
+plugins. See [[RCS_details|rcs/details]] for some more info.
+
+RCS plugins must register a number of hooks. Each hook has type 'rcs', 
+and the 'id' field is set to the name of the hook. For example:
+       
+       hook(type => "rcs", id => "rcs_update", call => \&rcs_update);
+       hook(type => "rcs", id => "rcs_prepedit", call => \&rcs_prepedit);
+
+#### `rcs_update()`
+
+Updates the working directory with any remote changes.
+
+#### `rcs_prepedit($)`
+
+Is passed a file to prepare to edit. It can generate and return an arbitrary
+token, that will be passed into `rcs_commit` when committing. For example,
+it might return the current revision ID of the file, and use that
+information later when merging changes.
+
+#### `rcs_commit($$$;$$)`
+
+Passed a file, message, token (from `rcs_prepedit`), user, and ip address.
+Should try to commit the file. Returns `undef` on *success* and a version
+of the page with the rcs's conflict markers on failure.
+
+#### `rcs_commit_staged($$$)`
+
+Passed a message, user, and ip address. Should commit all staged changes.
+Returns undef on success, and an error message on failure.
+
+Changes can be staged by calls to `rcs_add, `rcs_remove`, and
+`rcs_rename`.
+
+#### `rcs_add($)`
+
+Adds the passed file to the archive. The filename is relative to the root
+of the srcdir.
+
+Note that this should not commit the new file, it should only
+prepare for it to be committed when rcs_commit (or `rcs_commit_staged`) is
+called. Note that the file may be in a new subdir that is not yet in
+to version control; the subdir can be added if so.
+
+#### `rcs_remove($)`
+
+Remove a file. The filename is relative to the root of the srcdir.

 
 

-Each RCS plugin must support all the `IkiWiki::rcs_*` functions.
-See IkiWiki::RCS::Stub for the full list of functions. It's ok if
-`rcs_getctime` does nothing except for throwing an error.
+Note that this should not commit the removal, it should only prepare for it
+to be committed when `rcs_commit` (or `rcs_commit_staged`) is called. Note
+that the new file may be in a new subdir that is not yet in version
+control; the subdir can be added if so.

 
 

-See [[RCS_details|rcs/details]] for some more info.
+#### `rcs_rename($$)`
+
+Rename a file. The filenames are relative to the root of the srcdir.
+
+Note that this should not commit the rename, it should only
+prepare it for when `rcs_commit` (or `rcs_commit_staged`) is called.
+The new filename may be in a new subdir, that is not yet added to
+version control. If so, the subdir will exist already, and should
+be added to revision control.
+
+#### `rcs_recentchanges($)`
+
+Examine the RCS history and generate a list of recent changes.
+The parameter is how many changes to return.
+
+The data structure returned for each change is:
+
+       {
+               rev => # the RCSs id for this commit
+               user => # name of user who made the change,
+               committype => # either "web" or the name of the rcs,
+               when => # time when the change was made,
+               message => [
+                       { line => "commit message line 1" },
+                       { line => "commit message line 2" },
+                       # etc,
+               ],
+               pages => [
+                       {
+                               page => # name of page changed,
+                               diffurl => # optional url to a diff of changes
+                       },
+                       # repeat for each page changed in this commit,
+               ],
+       }
+
+#### `rcs_diff($)`
+
+The parameter is the rev from `rcs_recentchanges`.
+Should return a list of lines of the diff (including \n) in list
+context, and the whole diff in scalar context.
+
+#### `rcs_getctime($)`
+
+This is used to get the page creation time for a file from the RCS, by looking
+it up in the history.
+
+It's ok if this is not implemented, and throws an error.
+
+#### `rcs_receive()`
+
+This is called when ikiwiki is running as a pre-receive hook (or
+equivalent), and is testing if changes pushed into the RCS from an
+untrusted user should be accepted. This is optional, and doesn't make
+sense to implement for all RCSs.
+
+It should examine the incoming changes, and do any sanity 
+checks that are appropriate for the RCS to limit changes to safe file adds,
+removes, and changes. If something bad is found, it should exit
+nonzero, to abort the push. Otherwise, it should return a list of
+files that were changed, in the form:
+
+       {
+               file => # name of file that was changed
+               action => # either "add", "change", or "remove"
+               path => # temp file containing the new file content, only
+                       # needed for "add"/"change", and only if the file
+                       # is an attachment, not a page
+       }
+
+The list will then be checked to make sure that each change is one that
+is allowed to be made via the web interface.

 
 ### PageSpec plugins
 
 
 ### PageSpec plugins
 


@@ -636,16 +896,95 @@ IkiWiki::FailReason object if the match fails.
 
 ### Setup plugins
 
 
 ### Setup plugins
 

-The ikiwiki setup file is loaded using a pluggable mechanism. If you
-look at the top of [[ikiwiki.setup]], it starts with 
-'use IkiWiki::Setup::Standard', and the rest of the file is passed to
-that module's import method.
+The ikiwiki setup file is loaded using a pluggable mechanism. If you look
+at the top of a setup file, it starts with 'use IkiWiki::Setup::Standard',
+and the rest of the file is passed to that module's import method.

 
 It's possible to write other modules in the `IkiWiki::Setup::` namespace that
 can be used to configure ikiwiki in different ways. These modules should,
 when imported, populate `$IkiWiki::Setup::raw_setup` with a reference
 
 It's possible to write other modules in the `IkiWiki::Setup::` namespace that
 can be used to configure ikiwiki in different ways. These modules should,
 when imported, populate `$IkiWiki::Setup::raw_setup` with a reference

-to a hash containing all the config items.
+to a hash containing all the config items. They should also implement a
+`gendump` function.
+
+By the way, to parse a ikiwiki setup file and populate `%config`, a
+program just needs to do something like:
+`use IkiWiki::Setup; IkiWiki::Setup::load($filename)`
+
+### Function overriding
+
+Sometimes using ikiwiki's pre-defined hooks is not enough. Your plugin
+may need to replace one of ikiwiki's own functions with a modified version,
+or wrap one of the functions.
+
+For example, your plugin might want to override `displaytime`, to change
+the html markup used when displaying a date. Or it might want to override
+`IkiWiki::formattime`, to change how a date is formatted. Or perhaps you
+want to override `bestlink` and change how ikiwiki deals with [[WikiLinks|ikiwiki/WikiLink]].
+
+By venturing into this territory, your plugin is becoming tightly tied to
+ikiwiki's internals. And it might break if those internals change. But
+don't let that stop you, if you're brave.
+
+Ikiwiki provides an `inject()` function, that is a powerful way to replace
+any function with one of your own. This even allows you to inject a
+replacement for an exported function, like `bestlink`. Everything that
+imports that function will get your version instead. Pass it the name of
+the function to replace, and a new function to call. 
+
+For example, here's how to replace `displaytime` with a version using HTML 5
+markup:
+
+       inject(name => 'IkiWiki::displaytime', call => sub {
+               return "<time>".formattime(@_)."</time>";
+       });
+
+Here's how to wrap `bestlink` with a version that tries to handle
+plural words:
+
+       my $origbestlink=\&bestlink;
+       inject(name => 'IkiWiki::bestlink', call => \&mybestlink);
+
+       sub deplural ($) {
+               my $word=shift;
+               $word =~ s/e?s$//; # just an example :-)
+               return $word;
+       }
+
+       sub mybestlink ($$) {
+               my $page=shift;
+               my $link=shift;
+               my $ret=$origbestlink->($page, $link);
+               if (! length $ret) {
+                       $ret=$origbestlink->($page, deplural($link));
+               }
+               return $ret;
+       }
+
+### Javascript
+
+Some plugins use javascript to make ikiwiki look a bit more web-2.0-ish.
+
+All javascript code should be put in `.js` files in the `javascript`
+underlay, and plugins using those files can enable use of the underlay by
+calling `add_underlay("javascript");` in their `import` function.
+
+You'll have to arrange for `<script>` tags to be added to the pages that
+use your javascript. This can be done using a `format` hook.
+
+Ikiwiki provides some utility functions in `ikiwiki.js`, for use by other
+javascript code. These include:
+
+#### `getElementsByClass(cls, node, tag)` 
+
+Returns an array of elements with the given class. The node and tag are
+optional and define what document node and element names to search.
+
+#### `hook(name, call)`
+
+The function `call` will be run as part of the hook named `name`.
+
+Note that to hook into `window.onload`, you can use the `onload' hook.
+
+#### `run_hooks(name)`

 
 

-By the way, to parse a ikiwiki setup file, a program just needs to
-do something like:
-`use IkiWiki::Setup; my %setup=IkiWiki::Setup::load($filename)`
+Runs the hooks with the specified name.