parameters: `cgi`, `session`, and `form`. These are, respectively, the
`CGI` object, the user's `CGI::Session`, and a `CGI::FormBuilder`.
-Each time a form is set up, the formbuilder_setup hook is called.
-Typically the formbuilder_setup hook will check the form's title, and if
+Each time a form is set up, the `formbuilder_setup` hook is called.
+Typically the `formbuilder_setup` hook will check the form's title, and if
it's a form that it needs to modify, will call various methods to
add/remove/change fields, tweak the validation code for the fields, etc. It
will not validate or display the form.
This is the standard gettext function, although slightly optimised.
+#### `urlto($$)`
+
+Construct a relative url to the first parameter from the second.
+
+#### `targetpage($$)`
+
+Passed a page and an extension, returns the filename that page will be
+rendered to.
+
## RCS plugins
ikiwiki's support for revision control systems also uses pluggable perl