[REQUIREMENT FOR 1.1] Choice group should allow attributes

Description:

Allow choice groups to include attributes. By this the following
use cases could be covered:

   * allow only certain combinations of attributes resp. attribute
     groups

     Example: Allow either the definition of an attribute name or
     a reference to an element:

       <A id="x" name="some.name"/>
       <A idref="x"/>

     Compare this to the content model of XLink attributes where
     only certain attribute combinations are allowed.


   * make it possible to allow only certain combinations between
     attributes and elements

     Example: Reference to an element which is out of scope

       <A id="x" a="5"/>
       <B idref="x"/>

     can be used *instead of* a local element

       <B>
         <A a="5"/>
       </B>

     Compare this to the definition of the XML W3C Schema where

       <xsd:element>

     either refer to a global definition or is defined locally.


Michael


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   PENTAPRISMA TECHNOLOGIES GmbH
   www.pentaprisma.com

     Michael Grübsch

     phone:  +49 (361) 4262-266
     fax:    +49 (361) 4262-261
     mailto: michael.gruebsch at pentaprisma.com
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