[XML-SIG] RELAX in lieu of XML Schema?
Mike Olson
Mike.Olson@fourthought.com
Mon, 24 Apr 2000 09:31:42 -0600
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Michael McLay wrote:
> Andrew M. Kuchling writes:
> > Andy Heath writes:
> > >Are you guys doing anything about XML Schema?
> > >
> > >I know the spec is not out there in any final'ish form
> > >yet but IMHO the whole world will go that way when it is.
> >
> > I don't know if anyone is working on XML Schema support, but your
> > message gave me the impetus to go to www.w3.org to take a look at the
> > working drafts.
> >
> > To my horror, the two parts of the XML schema WDs are 520K and 360K of
> > HTML; that's huge! (XML 1.0 is 188K.) Didn't people want schemas
> > because they thought DTD syntax was too complicated?
>
> The Schema committee lost control of the scope of the project. A
> typical standards committee mistake. Yet another standard that may
> have become so complex that it will never be consistently
> implemented. I'd like to see XML Schema available for Python, but I'd
> be happy with any DTD replacement mechanism be used that allows typing
> information and namespaces to be managed.
>
What about Schematron? The nice thing about this is that it can be validated
with a XSLT processor. There is a stylesheet with 4XSLT to do this. You run
the stylesheet against the Schema file, and it produces a new stylesheet. You
then apply this stylesheet to your data and it reports errors and warnings.
Mike
>
> Has anyone looked at RELAX, http://www.xml.gr.jp/relax/ ? It is a
> smaller and easier to implement alternative to XML Schema. Here's a
> quote from an article about RELAX that sums up why I think it might be
> a good first step towards adding schema capabilities to Python.
>
> Murata had hit the 80/20 mark that they [the XML Schema committee]
> had missed. RELAX core could provide a much easier on-ramp to
> schemas for application and schema authors than the W3C draft
> which is not modular.
>
> [...]
>
> Our First Take. We share the stunned admiration for Murata's lone
> samurai charge. On first analysis, RELAX appears to combine greater
> simplicity in approach, exposition and execution with greater power-a
> compelling combination under any circumstances. Given the low but
> omnipresent level of grumbling over the length, complexity and
> compromises of the W3C spec, RELAX will be given every chance to live
> up to its claims.
>
> Backing up his claim to ease of implementation, Murata's group
> already has made available a Java converter from DTDs to RELAX and a
> validator written in C++,with source code to come under an open source
> license. As Sperberg-McQueen indicated, ultimately adoption rests with
> the marketplace. One very strong point in favor of RELAX is that it
> can be implemented without ripping out existing XML processors and
> APIs. Because the Core module is a direct DTD replacement, no
> extensions are required to DOM and SAX implementations. RELAX grammar
> validation, with datatypes, can be added as a subsequent step.
>
> - http://www.seyboldreports.com/News/2000/20000307.html
>
> The C++ code isn't available in a format I recognize. The file name
> is regular1.lzh. The strings function located 51 .cpp file names and
> 120 .h file names. I would assume that the code could be added to the
> XML package as an optional post DOM processing step. Someone with
> SWIG or SIP experience could probably have the new module with RELAX
> capability up and running quickly. I don't see a down side to adding
> RELAX as a feature of the XML package. An XML Schema processing
> engine could be added along side of RELAX when and if XML Schema
> starts to be adopted widely.
>
> An article on RELAX at http://www.xml.com/pub/2000/02/xtech/relax.html
> also includes a review of Paul Prescod's EasySAX. Did I miss this
> article being referenced on this mailing list? There doesn't seem to
> be list of articles on Python and XML in the xml-sig pages. EasySAX
> was also described in http://www.javaworld.com/jw-03-2000/jw-03-xmlshow.html
>
> _______________________________________________
> XML-SIG maillist - XML-SIG@python.org
> http://www.python.org/mailman/listinfo/xml-sig
--
Mike Olson Senior Consultant
mike.olson@fourthought.com (303)583-9900 x 102
Fourthought, Inc. http://Fourthought.com
Software-engineering, knowledge-management, XML, CORBA, Linux, Python
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Michael McLay wrote:
<blockquote TYPE=CITE>Andrew M. Kuchling writes:
<br> > Andy Heath writes:
<br> > >Are you guys doing anything about XML Schema?
<br> > >
<br> > >I know the spec is not out there in any final'ish form
<br> > >yet but IMHO the whole world will go that way when it is.
<br> >
<br> > I don't know if anyone is working on XML Schema support, but
your
<br> > message gave me the impetus to go to www.w3.org to take a look
at the
<br> > working drafts.
<br> >
<br> > To my horror, the two parts of the XML schema WDs are 520K
and 360K of
<br> > HTML; that's huge! (XML 1.0 is 188K.) Didn't people
want schemas
<br> > because they thought DTD syntax was too complicated?
<p>The Schema committee lost control of the scope of the project.
A
<br>typical standards committee mistake. Yet another standard that
may
<br>have become so complex that it will never be consistently
<br>implemented. I'd like to see XML Schema available for Python,
but I'd
<br>be happy with any DTD replacement mechanism be used that allows typing
<br>information and namespaces to be managed.
<br> </blockquote>
What about Schematron? The nice thing about this is that it can be
validated with a XSLT processor. There is a stylesheet with
4XSLT to do this. You run the stylesheet against the Schema file,
and it produces a new stylesheet. You then apply this stylesheet
to your data and it reports errors and warnings.
<p>Mike
<br>
<blockquote TYPE=CITE>
<br>Has anyone looked at RELAX, <a href="http://www.xml.gr.jp/relax/">http://www.xml.gr.jp/relax/</a>
? It is a
<br>smaller and easier to implement alternative to XML Schema. Here's
a
<br>quote from an article about RELAX that sums up why I think it might
be
<br>a good first step towards adding schema capabilities to Python.
<p> Murata had hit the 80/20 mark that they [the XML
Schema committee]
<br> had missed. RELAX core could provide a much easier
on-ramp to
<br> schemas for application and schema authors than
the W3C draft
<br> which is not modular.
<p> [...]
<p> Our First Take. We share the stunned admiration for
Murata's lone
<br> samurai charge. On first analysis, RELAX appears
to combine greater
<br> simplicity in approach, exposition and execution
with greater power-a
<br> compelling combination under any circumstances.
Given the low but
<br> omnipresent level of grumbling over the length,
complexity and
<br> compromises of the W3C spec, RELAX will be given
every chance to live
<br> up to its claims.
<p> Backing up his claim to ease of implementation, Murata's
group
<br> already has made available a Java converter from
DTDs to RELAX and a
<br> validator written in C++,with source code to come
under an open source
<br> license. As Sperberg-McQueen indicated, ultimately
adoption rests with
<br> the marketplace. One very strong point in favor
of RELAX is that it
<br> can be implemented without ripping out existing
XML processors and
<br> APIs. Because the Core module is a direct DTD replacement,
no
<br> extensions are required to DOM and SAX implementations.
RELAX grammar
<br> validation, with datatypes, can be added as a subsequent
step.
<p> - <a href="http://www.seyboldreports.com/News/2000/20000307.html">http://www.seyboldreports.com/News/2000/20000307.html</a>
<p>The C++ code isn't available in a format I recognize. The file
name
<br>is regular1.lzh. The strings function located 51 .cpp file names
and
<br>120 .h file names. I would assume that the code could be added
to the
<br>XML package as an optional post DOM processing step. Someone
with
<br>SWIG or SIP experience could probably have the new module with RELAX
<br>capability up and running quickly. I don't see a down side to
adding
<br>RELAX as a feature of the XML package. An XML Schema processing
<br>engine could be added along side of RELAX when and if XML Schema
<br>starts to be adopted widely.
<p>An article on RELAX at <a href="http://www.xml.com/pub/2000/02/xtech/relax.html">http://www.xml.com/pub/2000/02/xtech/relax.html</a>
<br>also includes a review of Paul Prescod's EasySAX. Did I miss
this
<br>article being referenced on this mailing list? There doesn't
seem to
<br>be list of articles on Python and XML in the xml-sig pages. EasySAX
<br>was also described in <a href="http://www.javaworld.com/jw-03-2000/jw-03-xmlshow.html">http://www.javaworld.com/jw-03-2000/jw-03-xmlshow.html</a>
<p>_______________________________________________
<br>XML-SIG maillist - XML-SIG@python.org
<br><a href="http://www.python.org/mailman/listinfo/xml-sig">http://www.python.org/mailman/listinfo/xml-sig</a></blockquote>
<pre>--
Mike Olson Senior Consultant
mike.olson@fourthought.com (303)583-9900 x 102
Fourthought, Inc. <A HREF="http://Fourthought.com">http://Fourthought.com</A>
Software-engineering, knowledge-management, XML, CORBA, Linux, Python</pre>
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