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RE: AW: [F&O] Casting to xs:NOTATION, xs:QName not clarified

From: Ashok Malhotra <ashok.malhotra@oracle.com>
Date: Thu, 27 Jan 2005 05:12:13 -0800
To: Frank Legler <legler@informatik.hu-berlin.de>, public-qt-comments@w3.org
Message-ID: <20050127051213813.00000003480@amalhotr-pc>

No, that is not correct.   

You can construct a QName or NOTATION from a string literal.

You can not cast to QName or NOTATION.

All the best, Ashok

> -----Original Message-----
> From: Frank Legler [mailto:legler@informatik.hu-berlin.de]
> Sent: Thursday, January 27, 2005 1:13 AM
> To: 'Ashok Malhotra'; public-qt-comments@w3.org
> Subject: AW: [F&O] Casting to xs:NOTATION, xs:QName not clarified
> 
> Ashok, thank you for your answer.
> 
> Did I understand you right?
> (1) We can both cast and construct xs:QName and xs:NOTATION
>     from string literals, i.e. the following expressions are valid:
>      "a" cast as xs:QName
>      xs:QName("a")
> (2) We cannot cast or construct xs:QName and xs:NOTATION
>     from strings in general, i.e. the following expressions are invalid:
>        fn:string(<a>b</a>) cast as xs:QName
>        xs:QName(xs:string("a"))
> 
> Could you please explain why it makes sense to prohibit the
> examples from (2)?
> 
> Regards,
> Frank
> 
> > -----Ursprüngliche Nachricht-----
> > Von: Ashok Malhotra [mailto:ashok.malhotra@oracle.com]
> > Gesendet: Thursday, January 27, 2005 2:39 AM
> > An: legler@informatik.hu-berlin.de; public-qt-comments@w3.org
> > Betreff: RE: [F&O] Casting to xs:NOTATION, xs:QName not clarified
> >
> > Frank:
> > My apologies!  I thought the issue had been clarified in the
> > ensuing discussion but, clearly, I was mistaken.
> >
> > When you cast, you, in general, cast an expression.  The
> > prohibition for casting from string to QName in the casting
> > section refers to this general case.  If you do have a string
> > literal you can construct a QName from it.
> >
> > If you feel strongly abt this, we can consider a change that
> > says "casting from string to QName is not allowed in general
> > but allowed in the special case that you are casting a string
> > literal" but this seems like a minor
> > corner case to me.
> >
> >
> > All the best, Ashok
> > > -----Original Message-----
> > > From: public-qt-comments-request@w3.org [mailto:public-qt-comments-
> > > request@w3.org] On Behalf Of Frank Legler
> > > Sent: Wednesday, January 26, 2005 2:57 PM
> > > To: public-qt-comments@w3.org
> > > Subject: RE: [F&O] Casting to xs:NOTATION, xs:QName not clarified
> > >
> > >
> > > Hello,
> > >
> > > I am sorry to repeat myself, but I did not
> > > receive a satisfying answer the last time.
> > >
> > > According to Ashok's mail from 5 Nov 2004 [1]
> > > and from 17 Jan 2005 [2] is it "possible to
> > > construct xs:QName and xs:NOTATION from string
> > > literals"
> > >
> > > Nevertheless the casting table in the F&O spec [3]
> > > prohibits the cast from xs:string to xs:QName
> > > and xs:NOTATION. Michael Rys pointed out that
> > > the table applies to both constructors and
> > > casts [4].
> > >
> > > My question is if this is
> > > (1) an error in the spec, i.e. the casting table
> > >     needs to be corrected?
> > > or
> > > (2) we indeed can construct xs:QName and
> > >     xs:NOTATION from xs:string but cannot cast it?
> > >
> > >
> > > Regards,
> > > Frank
> > >
> > > URLS:
> > > [1]
> > http://lists.w3.org/Archives/Public/public-qt-comments/2004Nov/0019.
> > > html
> > > [2]
> > http://lists.w3.org/Archives/Public/public-qt-comments/2005Jan/0023.
> > > html
> > > [3]
> > http://w3.org/TR/xpath-functions/#casting-from-primitive-to-primitive
> > > [4]
> > http://lists.w3.org/Archives/Public/public-qt-comments/2005Jan/0020.
> > > html
> > >
> 
Received on Thursday, 27 January 2005 13:13:09 UTC

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