link to alternative implementation

doc/todo/wikitrails.mdwn

@@ -1,17 +1,23 @@
 ## summary
 at times it is useful to have a guided tour or trail through a subset of the pages of a wiki; in pmwiki, this is implemented as [wikitrails](http://www.pmwiki.org/wiki/PmWiki/WikiTrails).
 
+### smcv's implementation
+
+... is the out-of-tree [[plugins/contrib/trail]] plugin, see there for details.
+
+### chrysn's implementation
+
 i'm working on a python xmlrpc plugin for ikiwiki to support wikitrails, both as a navigation feature (have "forward" and "back" links based on a sequence) and a modified inline that includes all pages in the trail with appropriate modifications (suitable for printing if necessary).
 
 the current status is published on `git://github.com/github076986099/ikiwiki-plugins.git`; as of now, i don't have a public demo of it.
 
 feedback on both the concept and the code is very much appreciated by [[discussion]] or [email](mailto:chrysn@fsfe.org).
 
-## usage
+#### usage
 
 two preprocessor commands are provided:
 
-### \[[!trail index="my_indexpage"]]
+##### \[[!trail index="my_indexpage"]]
 
 embeds a navigation object with forward and back links as well as an indicator of the current position in the trail.
 
@@ -19,15 +25,15 @@ if index is not specified, a suitable page up the path is used.
 
 this works very well together with the [[sidebar|plugins/sidebar]] plugin if the pages in a directory are roughly the same as the pages in the trail and the `index` is directory index page; just put the \[[!trail]] in the sidebar.
 
-### \[[!trailinclude index="my_indexpage"]]
+##### \[[!trailinclude index="my_indexpage"]]
 
 all pages linked from the index page are included in the same way as \[[!inline]] does, but in the proper sequence, with headings according to the indent in the source page and adoptions for the headings inside the page (a level 2 heading in a page that is a sub-sub-chapter in the whole trail will become a level 5 heading when trailincluded).
 
-## the index page
+#### the index page
 
 the index page is parsed as markdown; numbered lists and "`*`" bulleted lists are discovered.
 
-## current issues
+#### current issues
 
  * rebuilding --- currently, there is no propper rebuilding of pages (will use `will_render` and `add_depends`). care has to be taken of how not yet created pages play into this.
  * inline recursion --- there is simply no guard yet