Fwd: [Moderator Action] Question about GROUP and CHOICE combined

This is a forwarded message
From: ?? <mcha226@gmail.com>
To: "public-schemata-users@w3.org" <public-schemata-users@w3.org>
Date: Thursday, December 15, 2005, 10:48:59 PM
Subject: [Moderator Action] Question about GROUP and CHOICE combined

===8<==============Original message text===============
Apologies if this question is too easy or if I have not read the schema
documentation enough.

My schema is like this: There will be a choice between one of the two groups
a and b.

...
        <xs:choice>
                <xs:group ref="a"/>
                <xs:group ref="b"/>
        </xs:choice>
...

however if I have the following group declaration it will not pass. The
error message will say that "X" cannot appear in both groups.

  ...
        <xs:group name="a">
                <xs:sequence>
                        <xs:element ref="X"/>
                        <xs:element ref="Y"/>
                </xs:sequence>
        </xs:group>
        <xs:group name="b">
                <xs:sequence>
                        <xs:element ref="X"/>
                        <xs:element ref="Z"/>
                </xs:sequence>
        </xs:group>
  ...
  ...

The strange thing is that if I have the following combination it will
not work:
XY XY
XY XX

However the following will work:
XY YX
XX YX
XY YY

This means that it will only fail if the first element of both group is the
same. Anything else will pass. This seemed really strange
to a newbie like me. Is there anyway around it? By the way I am using the
validator from here:
http://tools.decisionsoft.com/schemaValidate.html
 Cheers
Mark

===8<===========End of original message text===========

Non-member posting

-- 
 Chris Lilley                    mailto:chris@w3.org
 Chair, W3C SVG Working Group
 W3C Graphics Activity Lead
 Co-Chair, W3C Hypertext CG