Constraints and CSS

Dear all,

During the F2F in Abingdon, I took away the action item to come up with
some text about "external" constraint information.

Looking forward to your feedback.

Best regards,
Christian
---

A look at vocabularies which can work with Cascading Stylesheets (e.g.
XHTML
and XML) reveals that they already have a means for capturing at least
some
of the constraints we have been discussing. To be specific, the CSS
property
"max-width" constrains box widths to a certain range.

Accordingly, with CSS we have the case were we may not want to
enforce an ITS-specific representation of max-width but rather use
what is already part of the native XML application (in the sense of
the combination of  XHTML instance and CSS). Of course, we need
to make sure that the semantics and domain (in the sense of allowed
values) of the ITS data category for constraints, and the are
compatible.

Once we principally have come to the conclusion that the CSS
"max-width" covers the ITS data category, we need to take care that
the CSS representation makes sense to ITS aware applications. This
may require:

1. a mapping declaration (see our discussion at
http://esw.w3.org/topic/its0504ReqPurposeSpecMap)
2. possibly special locator processing

With 'locator processing' I refer to the situation in which a linking
mechanism is
used in order to associate a vocabulary with a stylesheet. Examples:

A. Via special element: <LINK REL=StyleSheet HREF="style.css"
TYPE="text/css">
B. Via processing instruction: <?xml-stylesheet type="text/css"
href="style.css" media="all"?>

Obviously, in these case, processing expectations related to the mapping
declaration are
different from the ones where "internal" styling (ie. either with the
"style" element or the "style"
attribute) is used: Actual values are not related in the XML instance
but rather externally.