X-Git-Url: http://git.vanrenterghem.biz/git.ikiwiki.info.git/blobdiff_plain/82eac2d04eb9a3a2e52972a0219606ac292ee3b9..e75818572fff5256d16221a2b065b214d8cb9f5d:/doc/plugins/write.mdwn

diff --git a/doc/plugins/write.mdwn b/doc/plugins/write.mdwn
index 1b78f5900..2e11e6234 100644
--- a/doc/plugins/write.mdwn
+++ b/doc/plugins/write.mdwn
@@ -196,7 +196,6 @@ generating the page.
 
 	hook(type => "pagetemplate", id => "foo", call => \&pagetemplate);
 
-
 [[Templates|wikitemplates]] are filled out for many different things in
 ikiwiki, like generating a page, or part of a blog page, or an rss feed, or
 a cgi. This hook allows modifying the variables available on those
@@ -361,6 +360,13 @@ 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.
 
+### displaytime
+
+	hook(type => "displaytime", id => "foo", call => \&display);
+
+This hook can be registered to override the regular `displaytime` function.
+Only the last displaytime hook will be used.
+
 ### renamepage
 
 	hook(type => "renamepage", id => "foo", call => \&renamepage);
@@ -847,3 +853,82 @@ to a hash containing all the config items. They should also implement a
 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.
+
+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)`
+
+Runs the hooks with the specified name.