RE: [xml-dev] What happens if facets contradict each others?

["Michael Kay" <mike@saxonica.com>]

> Let me make my points clearer through an example. Let's say 
> the XML schema defines a new datatype as such:
> 
> <simpleType name="myDecimal">
>        <restriction base="decimal">
>                <maxInclusive value="0.0"></maxInclusive>
>                <enumeration value="1.0"></enumeration>
>                <enumeration value="2.0"></enumeration>
>                <enumeration value="3.0"></enumeration>
>        </restriction>
> </simpleType>
> 
> I checked this against Validome's XML Schema Validator
> (http://www.validome.org/grammar/) but it said the schema is 
> valid, although all enumeration values contradict the value 
> defined in maxInclusive.

The schema is indeed valid, but it defines a type that has no valid
instances, so an instance generator should refuse to generate any instances
of this type.

There are many other types you can define that have no valid instances, for
example a restriction of decimal with a pattern of "[A-Z]".

Michael Kay
http://www.saxonica.com/