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Atomic datatypes

From: Elena Litani <hlitani@jtcsv.com>
Date: Sun, 04 Feb 2001 15:52:08 -0500
Message-ID: <3A7DC0F8.11E919D1@jtcsv.com>
To: xmlschema-dev@w3.org
Hi, 

Are list/union datatypes considered to be 'atomic datatypes'?

Specs are not clear. 

According to [2.5.1.1 Atomic datatypes]:
"atomic datatypes can be either primitive or derived."
I would assume that list and union are atomic datatypes (since both are
derived).

However, if I read [2.5.1 Atomic vs. list vs. union datatypes], I would
assume that list and union are not atomic datatypes.

But note from Henry, seems to say that union might be atomic if union's
members are also atomic...?

I am truly confused.

Can you clarify, please?
Thank you,
Elena


-------- Original Message --------
Subject: Re: List and union varieties
Resent-Date: Fri, 2 Feb 2001 07:25:35 -0500 (EST)
Resent-From: xmlschema-dev@w3.org
Date: 02 Feb 2001 12:25:14 +0000
From: ht@cogsci.ed.ac.uk (Henry S. Thompson)
To: Michael Anderson <michael@research.canon.com.au>
CC: "xmlschema-dev@w3.org" <xmlschema-dev@w3.org>
References: <3A7661ED.3CF12466@research.canon.com.au>

Michael Anderson <michael@research.canon.com.au> writes:

> Hi all,
> I was wondering if a simple type can be a list of a simple type that has
> a variety of union.  The specifications seem inconsistent.
> 
> http://www.w3.org/TR/xmlschema-1/#cos-st-restricts says
> If the variety is list:
> 2.1 The item type definition must have a variety of atomic or union ....
> 
> while http://www.w3.org/TR/xmlschema-2/#atomic-vs-list says
> [ Definition:] List datatypes are those having values each of which
> consists of a finite-length sequence of values of an atomic datatype.

The _values_ must be atomic, but that atomicity may be acquired via a
union type, provided the union's members are also atomic, if you see
what I mean.

ht
-- 
  Henry S. Thompson, HCRC Language Technology Group, University of
Edinburgh
          W3C Fellow 1999--2001, part-time member of W3C Team
     2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
	    Fax: (44) 131 650-4587, e-mail: ht@cogsci.ed.ac.uk
		     URL: http://www.ltg.ed.ac.uk/~ht/
Received on Sunday, 4 February 2001 15:51:41 UTC

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