Re: [xml-dev] XML Schema - Enumerated List to Allow Blank Value

[Eddie Robertsson <erobertsson@allette.com.au>]

>
>
>><xs:simpleType name="myEnum">
>>    <xs:union>
>>        <xs:simpleType>
>>            <xs:restriction base="xs:NMTOKEN">
>>                <xs:enumeration value="A"/>
>>                <xs:enumeration value="B"/>
>>                <xs:enumeration value="C"/>
>>            </xs:restriction>
>>        </xs:simpleType>
>>        <xs:simpleType>
>>            <xs:restriction base="xs:string">
>>                <xs:enumeration value=""/>
>>            </xs:restriction>
>>        </xs:simpleType>
>>    </xs:union>
>></xs:simpleType>
>>
>>    
>>
>Why is this preferred to the more direct:
>
I'm not sure. Since the original question was about restricting the 
xs:NMTOKEN type I assumed there was an underlying reason for this 
choice. However, after thinking about this I can't really see any reason 
for deriving the enumeration from xs:NMTOKEN instead of directly from 
xs:string as in your example.

Cheers,
/Eddie

>><xs:simpleType name="myEnum">
>>        <xs:simpleType>
>>            <xs:restriction base="xs:string">
>>                <xs:enumeration value="A"/>
>>                <xs:enumeration value="B"/>
>>                <xs:enumeration value="C"/>
>>                <xs:enumeration value=""/>
>>            </xs:restriction>
>>        </xs:simpleType>
>></xs:simpleType>
>>    
>>
>
>?
>Michael Kay
>Software AG
>home: Michael.H.Kay@ntlworld.com
>work: Michael.Kay@softwareag.com 
>
>  
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