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Re: Simple Scheme Question

From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
Date: 28 Apr 2000 22:57:12 +0100
To: "Joseph M. Reagle Jr." <reagle@w3.org>
Cc: dbeech@us.oracle.com, Noah_Mendelson@lotux.com, murray@muzmo.com, xmlschema-dev@w3.org
Message-ID: <f5bitx17utj.fsf@cogsci.ed.ac.uk>
"Joseph M. Reagle Jr." <reagle@w3.org> writes:

> The present spec has got me feeling a bit muddled, so I need to take a step
> back. What is the difference between (1) a group, (2) a (choice | sequence |
> all), or (3) a set of element declarations within a complex type,
> <group>: "Model Group Definition Schema Components ... It provides for
> naming a model group for use by reference in the XML representation of
> complex type definitions and model groups."
> (<all> | <choice> | <sequence>): "Model Group Schema Components ..." Adds
> semantics about the occurrence and order of the element declarations. Needs
> to be named via a group if it is to be used elsewhere.
> element declarations within a complex type: the complex type says whether
> the content model is (elementOnly | empty | mixed | textOnly) but is there
> an implicit model group definition (<group>) or model group  (<all>,
> <choice>, <sequence>)? 

Implicit model group, as you say below.

> I think [1, 4.4.2] says if its elementOnly then its
> implicitly a sequence, says if its mixed then its implicitly a choice. Is
> this right? I like that you guys are being more explicit in the defaults in
> these interactions, but it stil can get quite hairy. (Maybe a table of all
> default values would be useful ... ?) 

I'm coming to feel the defaulting is/was a mistake, and we should just 
make the content of a complex type be (group | sequence | choice | all)?

  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 Friday, 28 April 2000 17:59:07 UTC

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