On Fri, 8 Mar 2002, Carl Lagoze wrote:
> Andy, is there any reason in your mind why we should NOT allow xHTML
> in the values of the simple schema. My first reaction is that it
> opens the door sufficiently to allow things like MathML but does not
> push it wide open into unrestricted land.
I'm not really sure... but my feeling is that 'simple DC' means simple
literal string values and *nothing* else.
Here's my thinking...
We need to have a shared understanding of what we mean by a 'simple DC'
application.
Currently, that understanding has to work across applications that are not
based on XML. I'm thinking here about applications that carry metadata
using non-XML encodings such as HTML4/meta, Z39.50/GRS-1, Z39.50/MARC, ...
Any two 'simple DC' applications should be able to exchange all their
metadata. Anything encoded in one 'simple DC' application, should be able
to be encoded in another with no loss of data.
'Simple DC' is our most dumbed-down form of metadata. It provides our
base level of interoperability between different services. (Simple DC is
the equivalent of the plain text rendered by, say, lynx - not the (X)HTML
page on which that rendering is based).
XHTML carried in DC element values does *not* feel like 'simple DC' to me.
I completely agree that it would be a useful thing to be able to do (and
at least one of the services I'm involved in would like to be able to do
it!) - but I wouldn't call it 'simple DC' and I don't think support for it
should appear in a 'simple DC' XML schema.
Finally, as an aside...
It seems to me that the problems associated with trying to embed
structured content within DC element values is the aspect of DC that we
understand least currently. I think we now have a good understanding of
qualified DC in terms of element refinement and encoding schemes. But we
still don't know how to handle structured content very well. For example,
we have the rather messy situation in which it is not clear if the DCMI
Box encoding scheme is a 'formatted string' or an 'XML application' or
both. I think this stems from an acknowledgement that we can do some
things in XML-based applications that we can't do in text-based
applications but without being quite sure how to handle that properly in
practice.
Andy.
> > -----Original Message-----
> > From: Roland Schwaenzl
> > [mailto:[log in to unmask]]
> > Sent: Friday, March 08, 2002 1:17 PM
> > To: [log in to unmask]
> > Subject: Re: Public Comment on DC-simple XML Schema declaration within
> > OAI
> >
> >
> > > From [log in to unmask] Fri Mar 8 16:30 MET 2002
> > > content-class: urn:content-classes:message
> > > MIME-Version: 1.0
> > > X-MimeOLE: Produced By Microsoft Exchange V6.0.5762.3
> > > Thread-Topic: Re: Public Comment on DC-simple XML
> > Schema declaration
> > > within OAI
> > > Thread-Index: AcHGrDpz/EG80hNpQAmDGuSf4riG1QACWQMg
> > > Date: Fri, 8 Mar 2002 10:30:05 -0500
> > > From: Carl Lagoze <[log in to unmask]>
> > > Subject: Re: Public Comment on DC-simple XML Schema
> > declaration within OAI
> > > Comments: cc: Herbert Van de Sompel <[log in to unmask]>
> > > To: [log in to unmask]
> > > Content-Transfer-Encoding: 8bit
> > > X-MIME-Autoconverted: from quoted-printable to 8bit by
> > scarlett.mathematik.Uni-Osnabrueck.DE id QAA20116
> > >
> > > Roland,
> > >
> > > Regarding point 1: The prohibition as you state it sound
> > pretty draconian; seems like some of the people originally
> > motivated OAI (eprints folks) would want mathML. Remind me
> > again, is there a solution that allows things like mathML but
> > forbid arbitrary other XML?
> >
> > >
> >
> > Sure, you could (!) do that. W3C's xml-schema-primer has an
> > example, with content restricted to XHTML:
> > http://www.w3.org/TR/xml-schema-0 sec.5.5. It's the example
> > preceding the textType example.
> > In particular table 4 in that section is quite useful as
> > summary of built in facilities.
> > There's a similar technique with attributes.
> >
> > One could try: http://www.w3.org/1998/Math/MathML for a namespace URI.
> >
> > There's some use of MathML embedded into XHTML -
> > (cf. processContents="skip" in the example cited above)
> >
> >
> > rs
> >
> >
> >
> > > Carl
> > >
> > > I've copied to Herbert Van de Somple because the MathML
> > thing might be of concern to him also.
> > >
> > >
> > >
> > > > -----Original Message-----
> > > > From: Roland Schwaenzl
> > > > [mailto:[log in to unmask]]
> > > > Sent: Friday, March 08, 2002 9:19 AM
> > > > To: [log in to unmask]
> > > > Subject: Re: Public Comment on DC-simple XML Schema
> > declaration within
> > > > OAI
> > > >
> > > >
> > > > Dears,
> > > >
> > > > with us it's now the time for reports rather than development.
> > > > I'll not be able to follow this discussion the coming week.
> > > >
> > > >
> > > > Let me try to summarize, what i understand currently from
> > the dc-xml
> > > > discussion.
> > > >
> > > >
> > > > 1. In OAi the use of dc:elements with the xml- simple
> > > > dataType "string" will (continue to) be required in
> > > > the mandatory part of OAi.
> > > > It could be, that OAi allows a dataType extension by
> > > > the xml:lang attribute.
> > > >
> > > > [In particular no mark-up from W3C's MathML or Ruby will
> > be allowed in
> > > > oai-dc records].
> > > >
> > > > 2. There are mixed views on (details of) requirements, design
> > > > and coding
> > > > for dcmi supported "plain-xml"-schemes.
> > > >
> > > >
> > > > Please correct me on mistaken points.
> > > >
> > > >
> > > > Best,
> > > > rs
> > > >
> > >
> >
>
Andy
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