Unnecessary restriction on span property

Dear XSL Editors,

The specification of the span property has a note on page 285 saying the following"

"This only has effect on areas returned by a flow; e.g. block-areas generated by
fo:block children of an fo:flow. Children and further descendants of these areas
take on the spanning characteristic of their parent."

If I understand this correctly, the span attribute is only allowed on direct
children of fo:flow and are ignored on any other flow object.

Isn't this very implementation-oriented? This looks like making a direct mapping
to span-reference-areas easier. It is also very unlike XML, which is always
tree-structured. Imagine using DocBook for writing a two-column article. The
title would typically span the two columns. In DocBook this would be a "title"
element inside a "section" element, for example.

Writing a style sheet for such a situation is difficult and unnatural. At some
point you reach an element that should span the columns. You might be several
levels inside a tree not knowing exactly where (on purpose by good design).
All those levels would have to be "closed" and "reopened" artificially. This
situation is very common. Another simple example is a figure in the middle of
a sequence of paragraphs. Such an element is rarely going to be high in the XML
tree.

There are products that seem to ignore the restriction and produce good results.
I therefore don't see why we should keep it. The complexity of cutting through
hierarchies should be in the XSL-FO processor, not in the style sheets.

Regards,

Werner.
-- 
Werner Donné  --  Re BVBA
Engelbeekstraat 8
B-3300 Tienen
tel: (+32) 486 425803	e-mail: [email protected]