UnitsML: Additional discussion for October meeting

["Peter J. Linstrom" <peter.linstrom@nist.gov>]

All,

    This message is part of the asynchronous discussion
for the October UnitsML TC meeting.

    During this meeting the idea of switching element
ids to type xml:id was briefly discussed. These attributes
are currently defined locally in the schema and are
restricted to content of type xsd:token. The advantage of
switching to xml:id is that generic tools could more
readily access components of a UnitsML document. However,
there are some potential issues to be considered before
making such a change:

1.) Would the restrictions of xsd:id invalidate some
    identifiers. I don't have a reference on this handy,
    but I'm pretty sure that xsd:id is more restrictive
    than xsd:token. Would some logical choices for IDs
    (codes) be invalidated by this change? I suspect that
    many applications will "use" UnitsML simply by recording
    the ID string for a unit in a database, so there is
    and incentive to use meaningful strings. This issue
    should be considered before making a change.

2.) Using xml:id would force all ID strings to be unique
    in a document. In general this is probably a good
    thing, but we probably should consider that in some
    cases people give the same name to units and the
    quantities they represent.

3.) It appears that use of xml:id can break Canonical XML:

    http://www.w3.org/TR/C14N-issues/#S3

    I don't think this is that big of an issue for UnitsML,
    except that XML Signature uses Canonical XML. This
    *might* be an issue since UnitsML will likely be included
    into other markup languages (which might want to use
    XML signature).

   I don't know what the UBL naming and design rules
say (if anything) about xml:id; it would be interesting
to see if they address this issue.

Peter Linstrom

======================================================
Peter J. Linstrom
NIST, Chemical and Biochemical Reference Data Division
Phone: (301) 975-5422
======================================================

----- Original Message ----- 
From: <carlisle@nist.gov>
To: <unitsml@lists.oasis-open.org>
Cc: <Robin.Barker@npl.co.uk>
Sent: Friday, October 17, 2008 2:10 PM
Subject: [unitsml] Groups - Teleconference Minutes for Oct 15-29, 2008, 
Meeting (telecon20081015.pdf) uploaded


> This meeting will continue asynchronously until Wednesday, Oct 29, 2008.
>
> -- Mr. Mark Carlisle
>
> The document named Teleconference Minutes for Oct 15-29, 2008, Meeting
> (telecon20081015.pdf) has been submitted by Mr. Mark Carlisle to the OASIS
> UnitsML TC document repository.
>
> Document Description:
>
>
> View Document Details:
> http://www.oasis-open.org/committees/document.php?document_id=29694
>
> Download Document:
> http://www.oasis-open.org/committees/download.php/29694/telecon20081015.pdf
>
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