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   Re: [xml-dev] Typing and paranoia

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Mike Champion wrote:

> Well, with all respect, that's just not the reality I live much of my 
> life in. Web services are often implemented with synthetic infosets that 
> are only
> serialized as XML at the very end of the road.

At the very end of the road, then, they're XML.  When they're sloshing 
around inside the Web Services machinery they're handy useful data 
structures that nobody should confuse with XML.

>  As
> Martin Gudgin says in the piece that Len quoted (disapprovingly?) 
> http://msdn.microsoft.com/webservices/understanding/default.aspx?pull=/library/en- 
> us/dnxml/html/xmlinfoset.asp
> "If a DOM tree sprouts, grows, withers and dies and is never serialized 
> using angle brackets" ... it *is* XML IMHO.  There is more (or less) to t
> he XML brand than the angle brackets, or else DOM, SOAP, XPath, and 
> XQuery (ahem, the W3C specs I have the most personal interest or 
> involvement with!) are not about "XML".  There's an
> awful lot of "XML" interoperability at the level of SAX events, DOM 
> trees, XPath or
> XQuery queries, SOAP messages, etc.

I disagree with so much of this paragraph that I'm going to have to 
number 'em:

1. A DOM tree is not XML.  It's related to XML, but if you pass me some 
instance of a DOM tree, it's not XML unless it's unicode characters with 
angle brackets.  I have the specifications on my side on this one and 
I'm not backing down.  I'm not denying that someone might want to pass 
DOM trees around, I'm just saying that this gives up most of the 
interoperability advantages of XML and shouldn't be billed as 
interchanging XML.

2. Indeed the XML brand grows worryingly, but it is terribly important 
for the integrity of that brand that when someone says "this data is 
available as XML", that they provide unicode characters with angle 
brackets on demand.

3. I have yet to encounter, in 21 years in the software business, any 
program-level facility, whether it be SAX events, DOM trees,  SQL APIs, 
POSIX, you name it, that offers the interoperability you get by 
exchanging XML messages.  If your SOAP messages are unicode characters 
with angle brackets, they're likely very interoperable.  If not, not. 
The only documented way to interchange any of these constructs at the 
moment is streams of text with embedded markup, and this is as it should 
be.  What you do in the privacy of your sandbox is entirely up to you, 
but don't pretend that it's XML and don't pretend that it's 
interoperable.  The only really interoperable APIs are those that are 
defined by a single implementation, e.g. Win32 and Apache APR and so on. 
  XML exists to get us out from under that rock.

There's a deep tension here that won't go away.  Some of us really 
REALLY want to be able to deal with the bits on the wire and REALLY like 
the open-ness and interoperability that gives us.  Others really REALLY 
want to take the bits on the wire away and present us instead with an 
API that has 117 entry points averaging 5 arguments and try to convince 
us that this is somehow equivalent.  XML, for the first time in my 
professional career, represents a consensus on interoperability: that it 
is achieved by interchanging streams of characters with embedded markup. 
  Since about 15 seconds after XML's release, the API bigots have been 
trying to recover from this terrible mistake and pretend that the syntax 
is ephemeral and the reality is the data structure, just read chapters 3 
through 27 of the API spec, buy the programmer's toolkit, sign up for 
professional services and hey-presto, you'll be able to access your own 
data, isn't that wonderful!?!?

But you're not going to take the bits on the wire away from us without a 
huge messy noisy fight down to the last ditch. -Tim


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