Re: RIF Working Group needs namespace name for xpath "op"

Sandro and Rule Interchange Format WG,

The XML Query WG and XSL WG discussed your suggestion for a namespace URI 
to associate with our "op" prefix [1] at our joint meeting on May 13 [2].

Our WGs created the "op" functions as a definitional mechanism used to 
convey the behavior of operators such as "+", "idiv", etc. We made an 
explicit decision not to associate a namespace URI with the "op" prefix in 
order to reinforce the message to our readers that these are not "real" 
functions and cannot be invoked in an XPath or XQuery expression with a 
function call. We revisited this decision and reaffirmed it.

We suggest that you define these operators in your own specification using 
a prefix and namespace URI  that reflects this (something like rif-op and 
http://www.w3.org/2008/rif-operators). These operators could then be 
defined by making reference to the "op" functions in XQuery 1.0 and XPath 
2.0 Functions and Operators.

                                                -- Andrew

[1] RIF Working Group needs namespace name for xpath "op" Sandro Hawke 
http://lists.w3.org/Archives/Public/public-qt-comments/2008Mar/0021.html

[2] Minutes: XML Query/XSL WG Joint Teleconference 366 Agenda 2008-05-13 
(Tim Kraska)
http://lists.w3.org/Archives/Member/w3c-xml-query-wg/2008May/0031.html

--------------------
Andrew Eisenberg
IBM
4 Technology Park Drive
Westford, MA  01886

andrew.eisenberg@us.ibm.com
Phone: 978-399-5158    Fax: 978-399-7012





Sandro Hawke <sandro@w3.org> 
Sent by: public-qt-comments-request@w3.org
03/04/2008 11:52 AM

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Subject
RIF Working Group needs namespace name for xpath "op"








I'm writing on behalf of the W3C Rule Interchange Format (RIF) Working
Group [1], for which I am W3C staff contact.  RIF-WG is charted to
develop an XML format for interchanging rules.  It is supposed to reuse
F&O where practical [2].

In general, this reuse is working well, but we have one small snag: the
operators don't have an XML namespace.  F&O explains why this is [3]:

    Functions defined with the op prefix are described here to underpin
    the definitions of the operators in [XML Path Language (XPath) 2.0],
    [XQuery 1.0: An XML Query Language] and [XSL Transformations (XSLT)
    Version 2.0]. These functions are not available directly to users, and
    there is no requirement that implementations should actually provide
    these functions. For this reason, no namespace is associated with the 
op
    prefix. For example, multiplication is generally associated with the *
    operator, but it is described as a function in this document: 

but RIF is an XML format, so it actually does need the namespace.

Has some namespace been defined yet? 

If not, I propose:
     http://www.w3.org/2005/xpath-operators

That namespace name is chosen to parallel the fn: prefix from [3]:
     http://www.w3.org/2005/xpath-functions 

Any comment?

We need to pick something for a Working Draft scheduled for publication
on 21 March.  We're planning to take that document to Last Call at the
end of May.

      -- Sandro

[1] http://www.w3.org/2005/rules/wiki/RIF_Working_Group
[2] http://www.w3.org/2005/rules/wg/charter.html#w3c-xml
[3] http://www.w3.org/TR/2007/REC-xpath-functions-20070123/