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Re: OWL/XML schema & example

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Wed, 22 Jul 2009 19:45:10 +0100
Message-Id: <8F10C591-C435-4B6F-B5CC-6396F8A38BBB@cs.man.ac.uk>
Cc: 'W3C OWL Working Group' <public-owl-wg@w3.org>
To: Antoine Zimmermann <antoine.zimmermann@deri.org>
On 22 Jul 2009, at 17:52, Antoine Zimmermann wrote:

> Bijan,
>
> Bijan Parsia wrote:
>> On 22 Jul 2009, at 17:01, Antoine Zimmermann wrote:
>>> Dear working group fellows,
>>>
>>> I've been pointed to an issue wrt the XML schema of the OWL/XML  
>>> syntax.
>>> First, the XSD file is enclosed by <pre> ... </pre> which breaks  
>>> its validity.
>> Yeah, a known problem.
>>> Second, the example XML ontology in the spec [2] is not validated  
>>> against the schema (without <pre> ... </pre>).
>> It is valid, but there's another issue with the "live from wiki"  
>> version...it entities all the ampersand, e.g.,
>>     <!ENTITY PN_CHARS_U    "&amp;PN_CHARS_BASE;|_">
>> Which, obviously, breaks that use of entities.
>
> Thanks. Why can't we just edit the file at w3.org? The problem  
> seems very easy to fix.

Hysterical raisons. Basically, wikiexperimentation and I believe we  
decided to wait until the next round to fix this once and for all.

>> If you cut and paste the text of the schema as it's rendered in a  
>> browser, it works fine and it validates the example.
>> For your convenience, I've put a clean, working copy of the schema  
>> here:
>>     http://www.cs.man.ac.uk/~bparsia/owl/owlxml.xsd
>> and here's the spec example with schemaLocation pointing to the  
>> clean schema:
>>     http://www.cs.man.ac.uk/~bparsia/owl/specExample.xml
>
> It works, but one validator [1] is still not happy with you input.

I don't find that one prima facie reliable. E.g., if I put the schema  
into the bottom box, I get:

Schema Error: System.Xml.Schema.XmlSchemaException: The  
targetNamespace parameter '' should be the same value as the  
targetNamespace 'http://www.w3.org/2002/07/owl#' of the schema. ...

Inconsistent results depending on whether it's downloading from my  
site or pulling it from a text box does not leave me filled with  
confidence :)

> [1] http://www.xmlme.com/Validator.aspx

1) I test with oXygen, generally. Saxon is the validator.

2) It works with:
	http://tools.decisionsoft.com/schemaValidate/
(Don't know what the engine is.)

3) And with:
	http://validate.openlaboratory.net/schema/
(Xerces C++)

Some others crap out in weird ways (stay away from ones aiming for  
XHTML or known vocabs...they don't even valdiate the schema).

I can't even load the w3c's page:
	http://www.w3.org/2001/03/webdata/xsv

4) Works with schematools:
	http://www.brics.dk/schematools/

java -jar schematools-all.jar -idocument specExample.xml -sxsd  
owlxml.xsd
0 validity errors detected.
[Validation time: 66859 ms]

(All this makes me realize I should get as many schema engines into  
my oxygen set up as possible. It makes this soooooo much easier. I  
think that on a windows machine, you'd get several more for free,  
e.g., xsv and .NET ones.)

5) Sun's msv:
java -jar msv-20081113/msv.jar owlxml.xsd specExample.xml
start parsing a grammar.
warnings are found. use -warning switch to see all warnings.
validating specExample.xml
the document is valid.

(I'm investigating the warnings, but they don't seem material.)

6) xmlstarlet which uses libxml2 I think.

xml val -s owlxml.xsd -e specExample.xml
specExample.xml - valid

I had someone with windows try XML Notepad and it barfed on the  
pattern (I think it's using MSXML but I don't know what version).

So, at least 5 distinct engines agree (saxon, xerces c++,  
schematools, msv, and libxml2).

Whew! Good to know :)

Cheers,
Bijan.
Received on Wednesday, 22 July 2009 18:40:57 GMT

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