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RE: Namespace considerations

From: Michael Rys <mrys@microsoft.com>
Date: Wed, 5 Mar 2003 12:15:18 -0800
Message-ID: <5C39F806F9939046B4B1AFE652500A3A049C5678@RED-MSG-10.redmond.corp.microsoft.com>
To: "Caroline Rioux" <crioux@decisionsoft.com>
Cc: <public-qt-comments@w3.org>

I don't quite understand your question.

If you do not import any schemata explicitly, then the prefix xf: is not
defined, however the xs: prefix is per default assigned to the "
http://www.w3.org/2001/XMLSchema" namespace.

Best regards
Michael

> -----Original Message-----
> From: Caroline Rioux [mailto:crioux@decisionsoft.com]
> Sent: Wednesday, March 05, 2003 2:19 AM
> To: Michael Rys
> Cc: public-qt-comments@w3.org
> Subject: RE: Namespace considerations
> 
> Thank you very much for your reply, it clears up a lot.
> 
> Just to be clear though (before I implement this ;-)), Jonathan
> mentions below that the datatypes in the
> "http://www.w3.org/2001/XMLSchema-datatypes" namespace are only
available
> if that schema is imported.
> 
> In the XPath 2.0 spec, section 2.6.2.1.1 (Basic XPath) it states that:
> 
> "In a Basic XPath implementation, the in-scope schema definitions
consist
> of a fixed set of 48 predefined type definitions. These include the 44
> built-in datatypes defined in [XML Schema], plus four additional
types:
> fn:yearMonthDuration,  fn:dayTimeDuration, xs:anySimpleType, and
> xs:anyType."
> 
> Wouldn't that mean that in a basic XPath2 implementation, without
> importing
> the above schema, only the third example below is legal?
> 
> <snip>
> 
> > > for example, if I bind xf to "http://www.w3.org/2001/XMLSchema"
and
> > > xs to "http://www.w3.org/2001/XMLSchema-datatypes", then which of
> these
> > > (or all?) are legal?
> > >
> > > 'cast as xs:string(xs:decimal("15.5"))'
> > > 'cast as xf:string(xs:decimal("15.5"))'
> > > 'cast as xf:string(xf:decimal("15.5"))'
> 
> Also,
> 
> > > On a different note, I thought that xs was bound to
> > > "http://www.w3.org/2001/XMLSchema" in the spec simply for
convenience.
> > > You seem to imply that it is a predefined prefix which is always
bound
> to
> > > "http://www.w3.org/2001/XMLSchema".
> >
> > This is correct.
> 
> [I assume you mean that Jonathan's implication was correct?] So does
this
> mean that this xs: binding takes precedence over any other xs: binding
> done by a user in a document?
> 
> Thanks very much for your help,
> Caroline
> 
> 
> On Tue, 4 Mar 2003, Michael Rys wrote:
> 
> > My apologies that nobody seem to have answered.
> >
> > See below for my reply.
> >
> > Best regards
> > Michael
> >
> > > -----Original Message-----
> > > From: Caroline Rioux [mailto:crioux@decisionsoft.com]
> > > Sent: Tuesday, March 04, 2003 7:19 AM
> > > To: public-qt-comments@w3.org
> > > Subject: Re: Namespace considerations
> > >
> > >
> > > Hi,
> > >
> > > I posted the following a few weeks ago.. if anyone could a look at
> > this,
> > > that would be great,
> > >
> > > Caroline
> > >
> > > --
> > > Caroline Rioux, Software Engineer           +44-1865-203192
> > > DecisionSoft Limited
> > http://www.decisionsoft.com
> > > XML Development and Services
> > >
> > > ---------- Forwarded message ----------
> > > Date: Wed, 19 Feb 2003 16:29:09 +0000 (GMT)
> > > From: Caroline Rioux <crioux@decisionsoft.com>
> > > To: Jonathan Robie <jonathan.robie@datadirect-technologies.com>
> > > Cc: public-qt-comments@w3.org
> > > Subject: Re: Namespace considerations
> > >
> > > Thanks for the quick reply,
> > >
> > > What I am unsure about though, is whether or not users of an
XPath2
> > > implementation can invoke constructors within either namespace?
> > >
> > > for example, if I bind xf to "http://www.w3.org/2001/XMLSchema"
and
> > > xs to "http://www.w3.org/2001/XMLSchema-datatypes", then which of
> > these
> > > (or all?) are legal?
> > >
> > > 'cast as xs:string(xs:decimal("15.5"))'
> > > 'cast as xf:string(xs:decimal("15.5"))'
> > > 'cast as xf:string(xf:decimal("15.5"))'
> > >
> > [Michael Rys] All are legal since they construct strings :-). And
even
> > if you remove the 's the above expressions should be legal.
> >
> > However note that as Jonathan points out below, xs:decimal is not
really
> > the same type as xf:decimal, instead xs:decimal is considered a
subtype
> > of xf:decimal.
> >
> > > On a different note, I thought that xs was bound to
> > > "http://www.w3.org/2001/XMLSchema" in the spec simply for
convenience.
> > > You seem to imply that it is a predefined prefix which is always
bound
> > to
> > > "http://www.w3.org/2001/XMLSchema".
> >
> > This is correct.
> >
> > >  Yet the F&O specs do use the
> > > xs: prefix for constructors, which is defined to be in the
> > > "http://www.w3.org/2001/XMLSchema-datatypes" namespace.
> >
> > [Michael Rys] This is a bug and should be fixed in the next version.
> > Ashok, please take note.
> >
> > > Thanks again for your help,
> > > Caroline
> >
> > [Michael Rys] Thanks for your comment.
> >
> > >
> > > On Wed, 19 Feb 2003, Jonathan Robie wrote:
> > >
> > > >
> > > > Hi Caroline,
> > > >
> > > > Good question! The short answer is that you can use
> > > > ""http://www.w3.org/2001/XMLSchema-datatypes" only if you import
> > that
> > > > schema. Even though the same set of datatypes are available
under
> > either
> > > > namespace, the datatypes in the two namespaces are not exactly
> > > identical.
> > > > If you go to the above URI, you can download the schema for
> > datatypes,
> > > and
> > > > you will see that it looks like the following excerpt:
> > > >
> > > > <schema xmlns="http://www.w3.org/2001/XMLSchema"
> > > >
targetNamespace="http://www.w3.org/2001/XMLSchema-
> > > datatypes"
> > > >              version="$Id: XMLSchema-datatypes.xsd,v 1.5
2001/03/16
> > > > 20:53:32 ht Exp $">
> > > >
> > > >    <simpleType name="string">
> > > >     <restriction base="string"/>
> > > >    </simpleType>
> > > >
> > > >    <simpleType name="boolean">
> > > >     <restriction base="boolean"/>
> > > >    </simpleType>
> > > >    <!-- SNIP -->
> > > >
> > > > For each datatype in the "http://www.w3.org/2001/XMLSchema"
> > namespace,
> > > it
> > > > defines a new datatype in the "http://www.w3.org/2001/XMLSchema-
> > > datatypes"
> > > > namespace, deriving it from the original by trivial restriction.
> > > >
> > > > You can import this schema like any other schema. It's often
easier
> > to
> > > > simply use the predefined xs: prefix, which always points to
> > > > "http://www.w3.org/2001/XMLSchema".
> > > >
> > > > Jonathan
> > > >
> > > > At 06:13 PM 2/18/2003 +0000, Caroline Rioux wrote:
> > > >
> > > > >Hi,
> > > > >
> > > > >I need some clarification on the namespaces used for
constructors
> > and
> > > > >datatypes.
> > > > >
> > > > >In the F&O spec, section 1.5 it says:
> > > > >
> > > > >The URIs of the namespaces are:
> > > > >   * http://www.w3.org/2001/XMLSchema-datatypes for
constructors
> > > > >   * http://www.w3.org/2002/11/xquery-operators for operators
> > > > >   * http://www.w3.org/2002/11/xquery-functions for functions.
> > > > >
> > > > >Which implies that constructors are in the
> > > > >http://www.w3.org/2001/XMLSchema-datatypes namespace
> > > > >
> > > > >In XML Schema Part 2: Datatypes section 3.1 (Namespace
> > Considerations)
> > > > >
> > > > >   The *built-in* datatypes defined by this specification are
> > designed
> > > to be
> > > > >   used with the XML Schema definition language as well as
other
> > XML
> > > > >   specifications. To facilitate usage within the XML Schema
> > definition
> > > > >   language, the *built-in* datatypes in this specification
have
> > the
> > > > >   namespace name:
> > > > >
> > > > >   http://www.w3.org/2001/XMLSchema
> > > > >
> > > > >   To facilitate usage in specifications other than the XML
Schema
> > > definition
> > > > >   language, such as those that do not want to know anything
about
> > > aspects of
> > > > >   the XML Schema definition language other than the datatypes,
> > each
> > > > >   *built-in* datatype is also defined in the namespace whose
URI
> > is:
> > > > >
> > > > >   http://www.w3.org/2001/XMLSchema-datatypes
> > > > >
> > > > >
> > > > >Does this mean that either namespace can be used, even in the
case
> > of
> > > > >construction?
> > > > >
> > > > >Thanks for any clarification,
> > > > >
> > > > >--
> > > > >Caroline Rioux, Software Engineer           +44-1865-203192
> > > > >DecisionSoft Limited
> > http://www.decisionsoft.com
> > > > >XML Development and Services
> > > >
> > > >
> > >
> > > --
> > > Caroline Rioux, Software Engineer           +44-1865-203192
> > > DecisionSoft Limited
> > http://www.decisionsoft.com
> > > XML Development and Services
> > >
> >
> >
> 
> --
> Caroline Rioux, Software Engineer           +44-1865-203192
> DecisionSoft Limited
http://www.decisionsoft.com
> XML Development and Services
Received on Wednesday, 5 March 2003 15:15:25 GMT

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