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RE: Namespace considerations

From: Michael Rys <mrys@microsoft.com>
Date: Tue, 4 Mar 2003 23:46:42 -0800
Message-ID: <5C39F806F9939046B4B1AFE652500A3A049C558B@RED-MSG-10.redmond.corp.microsoft.com>
To: "Caroline Rioux" <crioux@decisionsoft.com>, <public-qt-comments@w3.org>
Cc: "Ashok Malhotra" <ashokma@microsoft.com>

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
> 
Received on Wednesday, 5 March 2003 02:46:56 GMT

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