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Re: Finishing the XML-tagging discussion



At 06:48 PM 3/17/00 -0500, Simon St.Laurent wrote:
At 03:03 PM 3/17/00 -0800, Paul Hoffman / IMC wrote:
>"Growing" here means probably about one new type
>every week or so. This greatly reduces the power of the word "burden".

I think we have fundamental disagreements here about how many XML
vocabularies are in development today,

Nope, we agree that there are very many. Where we disagree is in how they will labelled when they are moved in MIME-based systems.


Your assumption appears to be that they will all follow the lead of IOTP and have their own sub-type tags. A different assumption is that they will mostly use text/xml and application/xml. Doing so makes them quite friendly to the random MIME parsers you envision. Each will have a unique DTD identifier, so there is no need to have their own subtype.

For the record, I don't know why the authors of IOTP chose to use a different sub-tag; they may have a very good reason. But my guess is that most XML-based applications that want to be found by generic XML parsers SHOULD use text/xml and application/xml.

I think we have another fundamental disagreement here.  Such 'specialized
systems' are already distributed by the millions, in the forms of IE 5 and
Mozilla.  Right now, they have pretty limited capabilities, but they're a
start.

Yes, we disagree here. There is no reason to automatically dispatch application/foo-xml in these XML systems. It may be valuable to manually dispatch those documents to your browser's XML parser, but rarely or never automatically. We are talking about trying to help automatic processing, not any processing.


Agents, that collapsed dream of a few years ago, are another likely
returning possibility that will also have the needs of these 'specialized
systems'.

I still await some good examples of these. Tim Bray gave a few far-fetched but possibly valid ones, but all of them would need to be used content sniffing even if we had -xml because each one really, really wanted to be sure to get all XML. The problem with the -xml system is that it has to be used 100% of the time in order to be useful in the given examples. Unfortunately, we're 100% sure that some content creators are going to end up sticking XML in text/plain and application/octet-stream bodies.


Add to that a number of folks out there implementing general architectures
for XML interchange and processing, some of them with plans for every
desktop a processor, and I think there are more than a few search engines
in the room.

If the search engine is XML-only, and only wanted to recognized things it had been told were XML (either by full type/subtype or subtypes that end in -xml), then, yes, you have a point. What's the chance of that? I think it's much more likely that a search engine is going to read every damn text object it sees and, if it looks like XML, do some smarter indexing in it.


Like Ned, I have nothing against -xml as a concept. I'm just convinced that the systems that use it will also reflexively resort to sniffing everything anyway, so why give the false impression that all subtags that go over XML should end in -xml? Let them sniff away.

--Paul Hoffman, Director
--Internet Mail Consortium