Hello;
I am struggling with the XML Schema documentation
(_W3C Recommendation, 2 May 2001_) more than with
nearly any technical specs I've read in 35 years of
programming. Someone who understands the Schema
syntax, please help!

[HT et al: for the future, please consider adding to
your team a specialist in *technical documentation*
who could help organise/present the design and syntax
of this excellent language in a lucid manner for
readers who are not immersed in its conceptual
framework; the orange-highlighted "[Definition:]"
parts help in this regard; JT, for one, seems to
understand the design and is somehow able to write
about it in a way that is technically precise but
more accesible.]

Our current problem -- with which I need help
urgently -- is basically this:
(a) we require a Schema Element type that accepts
tag Attributes and a Choice of child Elements; *plus*
(b) a RegEx Pattern constraint on string character
data that can appear between the tags of this Element
type.

[In our app, it is not acceptable to delimit the
constrained character data by a separate tags as a
child to the aforementioned Element type, such that
the character data can be constrained within a
simpleType Element.]

It is clear to me that a simpleType, per se, cannot
be extended.

Q1: Can we 'promote' a simpleType to a complexType
in some way, eg, the following?

<xs:simpleType name="base_Type-ST" abstract="true">
  <xs:restriction base="xs:string">
    <xs:pattern value="[...myRegEx...]"/>
  </xs:restriction>
</xs:simpleType>

<xs:complexType name="base_Type-CT" abstract="true">
  <xs:simpleContent>
    <xs:extension base="base_Type-ST"/>
  </xs:simpleContent>
</xs:complexType>

And, then use the 'promoted' type in our target
complexType declaration by extension, eg, the
following?

<xs:complexType name="target_Type" mixed="true">
  <xs:complexContent mixed="true">
    <xs:extension base="base_Type-CT">
      <xs:choice minOccurs="0" maxOccurs="unbounded">
        <xs:element name="location-specific_Comment"
type="xs:string"/>
      </xs:choice>
      <xs:attribute name="this_Element_ID"
type="xs:ID" use="required"/>
    </xs:extension>
  </xs:complexContent>
</xs:complexType>

Q2: Alternatively, is there a way to constrain the
string character-data content of a complexType by
restricting its type in another complexType
declaration, eg, something like the following?

<xs:complexType name="base_Type" mixed="true"
abstract="true">
  <xs:choice minOccurs="0" maxOccurs="unbounded">
    <xs:element name="location-specific_Comment"
type="xs:string"/>
  </xs:choice>
  <xs:attribute name="this_Element_ID" type="xs:ID"
use="required"/>
</xs:complexType>

<xs:complexType name="target_Type" mixed="true">
  <xs:simpleContent>
    <xs:restriction base="base_Type">
      <xs:simpleType>
        <xs:restriction base="xs:string">
          <xs:pattern value="[...myRegEx...]"/>
        </xs:restriction>
      </xs:simpleType>
    </xs:restriction>
  </xs:simpleContent>
</xs:complexType>

Many thanks in advance for help,  :-)
- Wyatt


From xan.gregg@j... Wed Aug 11 13:00:54 2004
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