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Simple Scheme Question

From: Joseph M. Reagle Jr. <reagle@w3.org>
Date: Fri, 28 Apr 2000 16:56:36 -0400
Message-Id: <3.0.5.32.20000428165636.020160f0@localhost>
To: ht@cogsci.ed.ac.uk (Henry S. Thompson), dbeech@us.oracle.com, Noah_Mendelson@lotux.com, murray@muzmo.com
Cc: xmlschema-dev@w3.org
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>)? 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 ... ?) 


[1] http://www.w3.org/TR/2000/WD-xmlschema-1-20000407/#declare-type

_________________________________________________________
Joseph Reagle Jr.   
W3C Policy Analyst                mailto:reagle@w3.org
IETF/W3C XML-Signature Co-Chair   http://www.w3.org/People/Reagle/
Received on Friday, 28 April 2000 16:57:26 GMT

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