xml-dev - Namespaces problems (SOAP, ...) and general problem of standard simplici

[Miloslav Nic <nicmila@idoox.com>]

XML standards get more and more complicated. That is nothing new and
many expressed this
concern before.  But have a look at following examples from SOAP and
CC/PP specifications: 

They are not getting right namespaces, a very simple and according to my
view very well though standard. Can we expect that people get right
something much more complicated, like XML schema?
Indeed you can achieve a lot with them. But to master them you must
master namespaces, regular expression, object oriented technologies,
XPath, ... . I expect that most schema authors will not have PhD in
computer science. So they will just use a tiny subset of them. 
My opinion is that several simple standards building each on other would
be the preffered path.
I know, the XML schema defines several levels of processor conformance
and several namespaces, but it is getting complicated. 
If there was one standard (or module) with about the same capabilities
as DTD just in XML, another module for regular expressions, another for
build-in datatypes, another for their extending. People would get
gradually used to it and then they could build upon their knowledge,
software authors could say my parser supports modules A,B and D (this
bit I like about DOM).

One Czech proverb says: "More often means less" 
It is nice to have standards which think of everything but it is much
more useful to have standards people can actually use and implement. 

And real life problems: 
SOAP v1.1
(http://static.userland.com/xmlRpcCom/soap/SOAPv11.htm)
 and I found several examples like this:

	<SOAP-ENV:Envelope
              
xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
              
SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"/>
                <SOAP-ENV:Header>
                    <t:Transaction
                      xmlns:t="some-URI"
                      xsi:type="xsd:int" mustUnderstand="1">
                        5
                    </t:Transaction>
                </SOAP-ENV:Header>
                <SOAP-ENV:Body>
                    <m:GetLastTradePriceResponse
                      xmlns:m="Some-URI">
                        <Price>34.5</Price>
                    </m:GetLastTradePriceResponse>
                </SOAP-ENV:Body>
	</SOAP-ENV:Envelope>

Note the Price element. It does not belong to any namespace although it
is meant to be a response from a function GetLastTradePrice Response.
Note that there is no default namespace so if anybody provides one the
Price moves there . If you are using a namespace aware browser you are
in big trouble. Real applications and books about SOAP are indeed using
the example cases so many people are getting wrong feeling for
namespaces. I am afraid that natural feeling this deliver is:
As <m:GetLastTradePriceResponse> is in "some-URI"  namespace then its
child Price must be there as well. 

And then I looked at  "CC/PP exchange protocol based on HTTP Extension
Framework"
http://www.w3.org/TR/NOTE-CCPPexchange

and found:
		<RDF xmlns="http://www.w3.org/TR/1999/PR-rdf-syntax-19990105#"
                     
xmlns:PRF="http://www.w3.org/TR/WD-profile-vocabulary#">
                  <Bag>
                   <Description about="HardwarePlatform">
                    <Defaults>
                     <Description PRF:Vendor="Nokia"
                                    PRF:Model="2160"
                                    PRF:Type="PDA"
                                    PRF:ScreenSize="800x600x24"
                                    PRF:CPU="PPC"
                                    PRF:Keyboard="Yes"
                                    PRF:Memory="16mB"
                                    PRF:Bluetooth="YES"
                                    PRF:Speaker="Yes" />
                    </Defaults>
                    <Modifications>
                     <Description PRF:Memory="32mB" />
                    </Modifications>
                   </Description>
                   <Description about="SoftwarePlatform">
                 .....
                 </RDF>

but RDF does not now about Default and Modification as default namespace
indicates.

So we have proposed standards which does not use correctly one of the
simplest specifications from XML world.


-- 
***************************************
*** Miloslav Nic                    ***
*** mailto: nicmila@idoox.com       *** 
*** support: http://zvon.vscht.cz   ***
***************************************

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