Re: DOCBOOK: Re: Linking in DocBook V5.0

[Bob Stayton <bobs@caldera.com>]

As we consider which elements will permit simple xlinks,
we also have to keep processing expectations in mind.
DocBook is in wide use because it is a practical tool to
produce content rendered in HTML and print.  We need to
understand what happens to rendering when we extend the
currently limited linking to other elements.

For example, even if we establish just simple xlinks for
inline elements, we will be permitting the case of an xlink
element as a child of another xlink element.  This is
certainly permitted by the XLink Rec.  As an
example, put a <replacable> inside a <classname>.  You want
the classname link to point to doc on the syntax for the
classname, and you want the replacable to point to an
explanation of what the options are for the replacable
text.  Semantically, the replacable is part of the
classname, so it is part of its xlink.  But HTML doesn't
permit <A> inside <A>, so it can't be expressed that way in
HTML.  In HTML, a stylesheet would have to close the
classname <A>, open the replacable <A>, close the
replacable <A>, and open a new classname <A> to finish the
rest of the classname.  What fun for stylesheet
writers!

This is why I think it is not yet practical to let 
<para> or other higher constructs be simple xlinks.  The
current delivery mechanisms can't express that very well.
And if it can't be expressed, I doubt it will be used much.

bobs
Bob Stayton                                 400 Encinal Street
Publications Architect                      Santa Cruz, CA  95060
Technical Publications                      voice: (831) 427-7796
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                                            email: bobs@caldera.com