Hi

How can I easily ensure that Xml document has elements in certain
order? I think it can be done with Xml schema, but I'd like to use
Xslt, because the validation is a part of Xslt transformations.

Xml document:
<Root>
  <Foo/>
  <Bar/>
  <Bar/>
  <Baz/>
  <Foo/> <!-- this is in the wrong position -->
</Root>

All elements don't necessary have to exist, but if they do they must
be in the right position. I'd like to have similar a function like this 
awk script:

$ echo "FooBarBarBazFoo" | awk '$0 !~ /^(Foo)*(Bar)*(Baz)*$/ { print "Error"}'


This is my attempt, quite ugly code. Is there a better way to do this ?
-----
 <xsl:template match="/Root">
    <xsl:apply-templates select="*"/>
  </xsl:template>

  <xsl:template match="Foo[not(preceding-sibling::*[name() != 'Foo'])]"/>

  <xsl:template match="Bar[not(preceding-sibling::*[name()!='Foo' and 
                                                    name()!='Bar'])]"/>

  <xsl:template match="Baz[not(preceding-sibling::*[name()!='Foo' and 
                                                    name()!='Bar' and 
                                                    name()!='Baz'])]"/>
  <xsl:template match="*">
    <xsl:message terminate="yes">
      <xsl:text>Error in: </xsl:text>
      <xsl:value-of select="name()"/>
    </xsl:message>
  </xsl:template>
-----

Thanks
-- 
  //  juho.jussila@i...
\X/