"Draft schema for character entity definition document type."
Posted to XML-DEV 2002-02-05 by Henry S. Thompson [ht@cogsci.ed.ac.uk]
with Subject: "A heavier-weight proposal for character entity definition."

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<?xml version='1.0'?>
<!DOCTYPE xs:schema SYSTEM "http://www.w3.org/2001/XMLSchema.dtd" >
<xs:schema targetNamespace="http://www.w3.org/2001/05/Character"
           xmlns="http://www.w3.org/2001/05/Character">
 <xs:annotation>
  <xs:documentation>A sketch of a schema for declaring character-valued entities.</xs:documentation>
  <xs:documentation>Issues:
1) Should there be an &lt;include> element to allow multiple documents to be
combined? (tentative answer - yes)

2) Should this be a full general entity mechanism with a value be allowed to be
any string? (tentative answer - no)

3) Should there be explicit support for documentation, e.g. via &lt;xs:any>?
(Tentative answer - yes)

4) Should the 'source' attribute be required? (tentative answer - no)?
  </xs:documentation>
 </xs:annotation>
 
 <xs:element name="characters">
  <xs:complexType>
   <xs:choice minOccurs="0" maxOccurs="unbounded">
    <xs:element ref="character"/>    
    <xs:any processContents="lax" namespace="##other"/>
   </xs:choice>
  </xs:complexType>
 </xs:element>
 
 <xs:element name="character">
  <xs:complexType>
   <xs:sequence>
    <xs:any processContents="lax" minOccurs="0" maxOccurs="unbounded"
            namespace="##other"/>
   </xs:sequence>
   <xs:attribute name="name" type="xs:NMTOKEN" use="required">
    <xs:annotation>
     <xs:documentation>What is the correct legacy type here, to correspond to
                        the right production from XML 1.0?</xs:documentation>
    </xs:annotation>
   </xs:attribute>
   <xs:attribute name="code" use="required">
    <xs:simpleType>
     <xs:union>
      <xs:simpleType>
       <xs:restriction base="xs:positiveInteger">
        <xs:annotation>
         <xs:documentation>Not sure _either_ of these values is correct</xs:documentation>
        </xs:annotation>
        <xs:minInclusive value="32"/>
        <xs:maxExclusive value="65536"/>
       </xs:restriction>
      </xs:simpleType>
      <xs:simpleType>
       <xs:restriction base="xs:token">
        <xs:annotation>
         <xs:documentation>Hex numbers from x0 thru xFFFF, case insensitive</xs:documentation>
        </xs:annotation>
        <xs:pattern value="x[0-9a-fA-F]{0,4}"/>
       </xs:restriction>
      </xs:simpleType>
     </xs:union>
    </xs:simpleType>
   </xs:attribute>
   <xs:attribute name="source" type="xs:anyURI"/>
   <xs:anyAttribute processContents="lax" minOccurs="0" maxOccurs="unbounded"
                    namespace="##other"/>
  </xs:complexType>
 </xs:element>
 
 <xs:element name="include">
  <xs:complexType>
   <xs:attribute name="source" type="xs:anyURI"/>
  </xs:complexType>
 </xs:element>
</xs:schema>

-- 
  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/