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

[chr at home.se]

On Wed, 9 Mar 2005, Patrick R. Michaud wrote:

> > 	http://www.pmwiki.org/wiki/Test/SomePage?trail=Test/TrailPage

> > It doesn't feel so good to force where the trail links are shown, so 
> > unless you modify the template to allocate space for the trail, I think 
> > we'll need a special markup which will then be replaced with the "dynamic" 
> > trail. 
> 
> I propose <<||>>, or perhaps even <<|{$Trail}|>>.  

Works for me. Hmm... what about generalizing this idea of extracting the
an argument from the URI? We could then in principle write the markup like
this:

	<<|(:URI-arg trail:)|>>

where (:URI-arg trail:) would extract the trail=... from the URI -- if it 
exists. You could imagine using (:URI-arg trail default=Main.TrailPage:) 
to set a default value for the variable. Maybe you'd prefer using

	{$URI-arg trail}

to extract an argument, and consequently

	<<|{$URI-arg trail}|>>

A slight problem is then what <<||>> should result in.. I'd probably vote
for it to show nothing at all.

> But this still feels like a halfway measure to me -- if we're going this far, 
> there ought to be some way to have the trail automatically appear 
> even w/o the markup.  But so far the mechanisms I can imagine for doing this
> aren't very pleasing.

Well... what are the options:
* Always allocate trail(s) their own space on the page template (this 
  could be good or bad depending on what your template looks like).
* Allow a directive to manually insert the "current" trail, if it exists
  (this includes using GroupHeader and/or GroupFooter)
* Others?

I think using GroupHeader/GroupFooter could work well for me... 
especially if there was someway to only insert this special markup 
if the argument is there... This means we'd need something like:

	(:if URI-arg-exists=trail:)
	Current trail: <<|{$URI-arg trail}|>>
	(:ifend:)

Anyway... I suspect that if we implement something like the above and 
people start using it, we'll soon get requests for this to be 
automatically inserted... then we can ask them where/how they'd like it 
inserted...

Btw, I think it would be nice if "directives" were always possible to
write in the "standard" way, i.e. using (:directive:)... that would be
easier for me to explain to newbies, then I could tell them:

	All PmWiki directives and commands can be written as (:...:).
	To see a list of available directives, go to this page...

I suspect it can be a bit overwhelming for a newbie to see all the various 
markup alternatives, especially "short forms" of them... at least it is 
easy to recognize (:...:) as some kind of directive (and then look in the 
documentation to see what it does).

An advantage with (:trail TrailPage:)  is that it's relatively easy to
understand from when looking at the wiki source, whereas <<|TrailPage|>>
is easy because it's sort of similar to the rendered result.

Anyway, I'm definitely not suggesting discarding <<|Trail|>>, rather that
we allow something like (:trail ...:) to be used as a synonym. And in
extension, that we always try to have a (:...:)-form of directives as a
backup.

/Christian

-- 
Christian Ridderström, +46-8-768 39 44               http://www.md.kth.se/~chr