be linkified and passed through markdown (or whatever engine is used to
htmlize the page) along with the rest of the page.
+### linkify
+
+ hook(type => "linkify", id => "foo", call => \&linkify);
+
+This hook is called to convert [[WikiLinks|WikiLink]] on the page into html
+links. The function is passed named parameters "page", "destpage", and
+"content". It should return the linkified content.
+
+Plugins that implement linkify must also implement a scan hook, that scans
+for the links on the page and adds them to `%links`.
+
+### scan
+
+ hook(type => "scan", id => "foo", call => \&scan);
+
+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`.
+
+The function is passed named parameters "page" and "content". Its return
+value is ignored.
+
### htmlize
hook(type => "htmlize", id => "ext", call => \&htmlize);
Given a page name and a destination file name (not including the base
destination directory), register that the page will result in that file
-being rendered. It's important to call this before writing to any file in
-the destination directory.
+being rendered.
+
+It's important to call this before writing to any file in the destination
+directory, and it's important to call it consistently every time, even if
+the file isn't really written this time -- unless you delete any old
+version of the file. In particular, in preview mode, this should still be
+called even if the file isn't going to be written to during the preview.
Ikiwiki uses this information to automatically clean up rendered files when
the page that rendered them goes away or is changes to no longer render