XML Schemata for RIF-FLD

Hi,

I would like to congratulate the WG for a thorough and careful work
on defining a rule standard for the web. It is important that the
current standard is based on previous attempts, such as RuleML, so
that interoperability with existing systems/prototypes is maintained.

Mostly, I would like to comment on the XML Schema for RIF-FLD (this may
be present on other RIF-related Schemata; I didn't check).

Specifically, in the FLDSkyline.xsd file there are two lines:

    <xs:include schemaLocation="FLDBaseline.xsd"/>
    <xs:redefine schemaLocation="FLDBaseline.xsd">

which actually should not co-exist, because xs:redefine implies that an
external schema file is included, but some of the definitions in there
are redefined. As a consequence, the above XML Schema file does not
validate in e.g. XMLSpy. Actually, only the redefine is needed.

Furthermore, I would like to remark that currently the XML Schema
definitions for various elements are not opted for modularity and
extensibility. For example, the definition of the element "Implies"
encapsulates its complex data type, not allowing for redefinition by an
extension of FLD.

For example, I'm working on a defeasible logic extension of RIF-FLD,
where I would like to add some attributes to indicate the rule type
(strict, defeasible, defeater). However, since the complexType of
"Implies" is not named, I cannot redefine it, including an attribute list.

I believe that since RIF is supposed to be a family of languages,
extending one another, this extensibility should be taken into account
for the XML Schemata.

Best Regards,
Nick


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* Dr. Nick Bassiliades, Assistant Professor                  *
* Dept. of Informatics, Aristotle University of Thessaloniki *
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Received on Sunday, 16 August 2009 15:18:25 UTC