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Re: XHTML2 and metainformation

From: Ernest Cline <ernestcline@mindspring.com>
Date: Mon, 19 May 2003 06:54:55 -0400
To: www-html@w3.org
CC: <a.powell@ukoln.ac.uk>
Message-ID: <3EC87FBF.16687.C2E7C7@localhost>

Andy Powell wrote:

> On Sat, 17 May 2003, Ernest Cline wrote:
> 
> > Andy Powell wrote:
> >
> > > In any case, it is worth noting that
> > >
> > > - all DC element names start with a lower-case letter (i.e. date rather
> > >   than Date)
> >
> > What DC does with its element names should not be a concern for XHTML.
> > As far as XHTML is concerned, DC could choose to use UPPERCASE,
> > CamelCase, or lowercase, or be case insensitive.  I used DC.Date rather
> > than dc.date in my example simply because that is what the version of
> > the DC standard I used recommended.
> 
> Again, that's fine... but DC examples were being used and, if, those
> examples were to make it thru into the finished recommendation then it
> would be good if they reflected current DCMI naming policies.

Makes perfect sense, provided that as seems almost certain, the DCMI 
working draft reaches recommendation status before XHTML2 does.

> > > - it seems sensible to move to a syntax that more closely mirrors the
> > >   encoding of DC in XML and RDF/XML (i.e. dc:date rather than DC.Date)
> >
> > Seems more like marketing than practicality to me.  Switching to a
> > colon instead of a period does not gain any new functionality and does
> > make backwards compatability more difficult.
> 
> Well, FWIW the reaction on the DC architecture mailing list to this
> proposal seems to have been quite positive.  People seem to recognise that
> the use of a period to separate a 'namespace prefix' (which is effectively
> what the 'DC.' in 'DC.Date' is) is oddly different from the other main
> encoding syntaxes used to carry metadata (XML and RDF/XML).
> 
> > Also, continuing to use
> > periods instead of switching to colons would seem to me to make the
> > task of writing ECMAScript or Java that interacts with meta-data
> > slightly easier.
> 
> Ah, I hadn't spotted that.  Can you explain why?

The main reason a switch to colon in this context would make things 
slightly more difficult is that since such scripts or programs will 
need to be backwards compatible, an extra comparison to be done while 
searching for the separator in DC meta-data embedded in (X)HTML <meta> 
elements.

Secondly, since the period is used as the object dereference marker, an 
ECMAScript script that wished to collect all of an (X)HTML's <meta> 
embedded meta-data could possibly use the raw name such as "dc.date" 
directly in the script instead of having to parse it beforehand.  This 
is an extremely minor point as the parsing should be done anyway in 
order to be able to handle unexpected name values.

Neither is a major concern, if the switch to colon provided sufficient 
benefit.  Switching to colon would make inserting meta-data easier to 
do, but keeping period will make collecting meta-data easier to do.  
The small per document benefit in either case is more likely to be 
noticable when working on large groups of documents.  Collection of 
meta-data is more likely to be done on groups of documents than 
insertion of meta-data.  As a result. I personally fail to see 
sufficient benefit to the change, hence my preference for keeping 
period as the separator.
Received on Monday, 19 May 2003 06:55:11 GMT

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