Response to NB2


Hi, thanks for the feedback and actually checking the schema.

Nick Bassiliades wrote:
> 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.

Thanks for catching this bug. While it validated in XSV, there were warnings. We thus dropped the xs:include and merged the two xs:redefine's in v. 1.4 of FLDSkyline.xsd (

> 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.

The current XML Schema started with two top-level modules (FLDBaseline.xsd and FLDSkyline.xsd). Further modularization, possibly including the fine-grained modularity you are proposing, is a topic of upcoming efforts.

Please acknowledge receipt of this email to <> (replying to this email should suffice). In your acknowledgment please let us know whether or not you are satisfied with the working group's response to your comment.


Last modified on 28 August 2009, at 13:41