[Petal] Multiple conditions?

[Ronald Hayden]

On Sunday, March 9, 2003, at 02:19  AM, jhiver at mkdoc.com wrote:

> It used to be documented somewhere, but I rewrote the docs (I'm still
> not satisfied with them...) and apparently it disapeared in the 
> process :)

Along these lines, what I would enjoy most in the docs are more 
examples.  I find myself having to guess a lot at how/where to use an 
item.  It would be great if each feature came with a snippet showing 
the feature in use.

Perhaps the website has more?  I've seen several mentions of it on this 
list, but I've only looked at the docs on CPAN.  Come to think of it, 
where is the website?  I've never noticed it in many Google searches.  
(Hmm, trying to find a Petal homepage is currently crashing Google!)

> Note that there is currently no trivial way of doing ORs...

Oops, and that's actually what I turned out to need!  Well consider it 
a feature request.  In general I don't like putting much logic (beyond 
condition and repeat) in the templates, but I'm finding that without an 
OR, I have to have the code be more involved than I'd like.  In this 
case, we're generating a "Figures, Listings, and Tables" TOC, and the 
template only wants to list a chapter if the chapter contains one of a 
set of elements.  The template has the ability to ask for a list of a 
type of element in a chapter, so what I'd like do to is something like:

<section petal:repeat="chapter $book/chapters">
	<chapter_section petal:condition="true:$chapter/descendants 'Figure' 
OR true:$chapter/descendants 'CodeListing' OR true:$chapter/descendants 
'Table'>
		...
	</chapter_section>
</section>

This way the template designers would be free to check for other kinds 
of elements in the document later, with no need for change to the code. 
   They could create entirely new kinds of sections without needing the 
code touched.  As it is now, I added a $book/lofat_chapters function to 
return only chapters that contain the elements in question.  This means 
that function has to stay in sync with what the template designers 
need, requiring both a template designer and a programmer for basic 
changes to be made.

If anyone has suggestions for a (simple!) solution, I'd love to hear 
them!

Hmm, perhaps it would work to do something like this:

<section petal:repeat="chapter $book/chapters_with_elements 'Figure' 
'CodeListing' 'Table'">

I'll go play with that now...

  -- Ron