Philipp <sicsicsic@f...> wrote in
<1207843345_2873@s...>:
> I'm learning W3C Schema 1.0 and have encountered a
> problem. I want to make a complex type which requires to
> contain exactly 1 instance of each of a list of elements
> (a, b, c) and at least once a choice of several other
> elements ( d1 | d2 | d3 ). This in any order.
> 
> I have come up with the following which is (unfortunately)
> invalid XSD 1.0: <complexType name="root">
>    <all>
>      <element name="a" type="string"></element>
>      <element name="b" type="string"></element>
>      <element name="c" type="string"></element>
>      <choice maxOccurs="unbounded" minOccurs="1">
>        <element name="d1" type="string"></element>
>        <element name="d2" type="string"></element>
>        <element name="d3" type="string"></element>
>      </choice>
>    </all>
> </complexType>

W3C's schema definition language was not designed for
defining arbitrarily complex grammars. If your document
format is well-structured, expressing it in XML Schema
should be easy. If it's not, try using a more powerful
schema definition language or check validity on the
application side.

-- 
"...a Netscape engineer who shan't be named once passed a
pointer to JavaScript, stored it as a string and later
passed it back to C, killing 30..." --Blake Ross