Oops, I think I missed a bit.  I think you have to do this in two stages:

1. Create the positive double by restricting double.

2. Extending the new positive double simpleType into a simpleContent.

e.g.

  <xs:simpleType name="positiveDouble">
    <xs:restriction base="xs:double">
      <xs:minExclusive value="0"/>
    </xs:restriction>
  </xs:simpleType>

  <xs:element name="wingarea">
    <xs:complexType>
      <xs:simpleContent>
        <xs:extension base="positiveDouble">
          <xs:attribute name="unit" use="optional" default="FT2">
            <xs:simpleType>
              <xs:restriction base="xs:string">
                <xs:enumeration value="M2"/>
                <xs:enumeration value="FT2"/>
              </xs:restriction>
            </xs:simpleType>
          </xs:attribute>
        </xs:extension>
      </xs:simpleContent>
    </xs:complexType>
  </xs:element>

HTH,

Pete.
--
=============================================
Pete Cordell
for XML to C++ data binding visit
http://www.tech-know-ware.com/lmx
(or http://www.xml2cpp.com)
=============================================

----- Original Message ----- 
From: "Pete Cordell" <petexmldev@t...>
To: "Jon Berndt" <jsb@h...>; <xmlschema-dev@w...>
Sent: Sunday, November 27, 2005 10:05 AM
Subject: Re: Attributes, simpleContent, etc.


>
> Hi Jon,
>
> Based on a quick look, try changing the line:
>
>        <xs:restriction base="xs:double">
>
> and its corresponding </xs:restriction> to:
>
>        <xs:extension base="xs:double">
>
> "simpleType" explanation[:-)]: you're extending (rather than restricting)
> the double simpleType into simpleContent.
>
> HTH,
>
> Pete.
> --
> =============================================
> Pete Cordell
> for XML to C++ data binding visit
> http://www.tech-know-ware.com/lmx
> (or http://www.xml2cpp.com)
> =============================================
>
> ----- Original Message ----- 
> From: "Jon Berndt" <jsb@h...>
> To: <xmlschema-dev@w...>
> Sent: Friday, November 25, 2005 5:23 PM
> Subject: Attributes, simpleContent, etc.
>
>
>>
>> I am just beginning to work with schemas. I'm having a little trouble
>> authoring a schema.
>> (I'm using the oXygenXML editor, if that matters). If there is a better
>> place for me to
>> post this, please let me know.
>>
>> I have an element in my XML document that looks as follows:
>>
>> <wingarea unit="FT2"> 174.0 </wingarea>
>>
>> The element is required, the content must be greater than 0, and the unit
>> can be one of
>> FT2 or M2 (the unit is optional, with FT2 being the default). I've read 
>> up
>> on this, but so
>> far I've been unsuccessful at making the correct schema, according to the
>> oXygen XML error
>> messages I get.
>>
>> Here's what I've got so far:
>>
>>  <xs:element name="wingarea">
>>    <xs:complexType>
>>      <xs:simpleContent>
>>        <xs:restriction base="xs:double">
>>          <xs:minExclusive value="0"/>
>>          <xs:attribute name="unit" use="optional" default="FT2">
>>            <xs:simpleType>
>>              <xs:restriction base="xs:string">
>>                <xs:enumeration value="M2"/>
>>                <xs:enumeration value="FT2"/>
>>              </xs:restriction>
>>            </xs:simpleType>
>>          </xs:attribute>
>>        </xs:restriction>
>>      </xs:simpleContent>
>>    </xs:complexType>
>>  </xs:element>
>>
>> I get an error message when I try and validate a document using this
>> schema:
>>
>> --- start error message ---
>>
>> "Complex Type Definition Representation Error for type
>> '#AnonType_wingarea'.  When
>> <simpleContent> is used, the base type must be a complexType whose 
>> content
>> type is simple,
>> or, only if restriction is specified, a complex type with mixed content
>> and emptiable
>> particle, or, only if extension is specified, a simple type. 'double'
>> satisfies none of
>> these conditions. URL: http://www.w3.org/TR/xmlschema-1/#src-ct"
>>
>> --- end error message ---
>>
>> I'd be grateful if someone can give me a "simpleType" of explanation of
>> where I've gone
>> wrong! Thanks.
>>
>> Jon Berndt
>> League City, TX



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