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RE: Is xdt:anyAtomicType itself atomic?

From: Michael Rys <mrys@microsoft.com>
Date: Wed, 10 Nov 2004 22:58:50 -0800
Message-ID: <BAE415CEAA831548800F68C44E905AF5E1B434@RED-MSG-60.redmond.corp.microsoft.com>
To: "Paul J. Lucas" <plucas@bea.com>, "Michael Kay" <mhk@mhk.me.uk>
Cc: <public-qt-comments@w3.org>

Note that numeric in our specification is not really a type at all but a
notational short-hand.

Best regards
Michael

> -----Original Message-----
> From: public-qt-comments-request@w3.org [mailto:public-qt-comments-
> request@w3.org] On Behalf Of Paul J. Lucas
> Sent: Wednesday, November 10, 2004 6:08 PM
> To: Michael Kay
> Cc: public-qt-comments@w3.org
> Subject: RE: Is xdt:anyAtomicType itself atomic?
> 
> 
> On Thu, 11 Nov 2004, Michael Kay wrote:
> 
> > What practical difference does it actually make whether
> xdt:anyAtomicType is
> > an atomic type or not?
> 
> 	The issue arrose indirectly during the implementation of our
> 	XQuery engine.  As part of our type system (which does full
> 	structural typing in addition to named typing), we've defined a
> 	"convenience" type to the developer:
> 
> 		numeric = xs:integer | xs:float | xs:double
> 
> 	I'm not clear on the exact details, but a developer who does
> 	our run time presumeably has the type of an expression set to
> 	numeric for things like addition, subtraction, etc.  Of course
> 	at runtime, there are actual values that also have a type.  The
> 	developer wanted to be able to ensure that an argument to
> 	something that expects an atomic type really is atomic.  A
> 	particular value had the type numeric, so he asked:
> 
> 		T.isAtomic()
> 
> 	He was surprised that it returned false.  I generalized his
> 	case: if numeric should be considered atomic, then so should
> 	anyAtomicType.  Hence my question to the committee.
> 
> 	We currently have anyAtomicType defined as a union and, as far
> 	as we can tell, it makes no difference... except in the case at
> 	hand.  I pointed out that he can get what he wants by instead
> 	doing:
> 
> 		T <= anyAtomicType
> 
> 	So the issue may (?) be moot.
> 
> 	- Paul
> 
Received on Thursday, 11 November 2004 06:58:56 UTC

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