[pmwiki-users] Re: Dynamic wiki trails - passing along the name of the trail page

[Patrick R. Michaud]

On Mon, Mar 14, 2005 at 09:37:34AM +0100, chr at home.se wrote:
> On 14 Mar 2005, John Rankin wrote:
> > Or, pmwiki contains SDV($TrailPage,TrailPage); and an
> > if (PageExists(FmtPageName("\$Group.$TrailPage",$pagename)))
> > add ?trail=Group.TrailPage to all urls. An administrator can
> > override the default $TrailPage at the group, wiki or farm level.
> > 
> > Er, but what happens if a page is on more than one trail??
> 
> Quite... which is why something is needed to indicate which trail the user 
> is currently traversing.
> [...]

No, I think there are other much cleaner ways to do this.  First, we can 
generalize the $TrailPage variable to be an array.  But since we're 
talking about automatically finding and placing pages on trails, let's 
call it $AutoTrailsFmt:

    $AutoTrailsFmt = array('$Group.TrailPage', 'Main.TrailPage',
      'PmWiki.DocumentationIndex');

This says that we want to automatically check to see if the current page
is on any of the listed trails.  Then, instead of trying to fix <<||>> 
and friends, or introduce a (:trailpage:) markup that has to be placed 
on trail pages, just define a (:trails:) markup that checks the pages
given by $AutoTrailsFmt and generates the appropriate <<||>> entries
for each trail that matches.  If none of the AutoTrails match, nothing
is generated.

(:trails:) can then be placed in a GroupHeader, GroupFooter, on  
individual pages, or in the skin template as appropriate.

We could possibly generalize this a bit further, by allowing the
list of pages in $AutoTrailsFmt to be read from a trail, but I'm not
sure how to do per-group trails in this case.

Or, if we now slap our hands to our collective foreheads, we find
that we can eliminate $AutoTrailsFmt entirely by defining the markup as

   (:trails {$Group}.TrailPage Main.TrailPage PmWiki.DocumentationIndex:)

which says to generate <<|trail|>> links for any of the listed trails 
that the current page happens to be a member of.  Now we've eliminated
?trail= from uris entirely, and made it fairly easy to do large-scale trail
manipulations at page, group, site, and skin levels.

A site-wide trail list could be maintained by the administrator and 
specified with something like

   (:trails {$SiteTrails}:)

and someday in the future we might envision things like

   (:trails category=TrailPages:)
   (:trails trail=Main.MasterTrailList:)

Pm