You haven't really said what the output looks like, but you (may) find
it simpler to test the output than the input, that way any file
inclusions are already handled:

<xsl:template match="document">
<xsl:variable name="x">
  <xsl:apply-templates/>
</xsl:variable>
<xsl:if test="not($x/node()[1]/self::section)">
  <xsl:message select="'something before first section'"/>
</xsl:if>
,xsl:sequence select="$x"/>
</xsl:template>


The test not($x/node()[1]/self::section)  is flagging any node before
section, if <section> gets transformed to (say) <h2> you'd need to
look for that instead, and also you may want to allow white space text
nodes, but that's just details....


David

On Fri, 6 Mar 2020 at 16:38, Trevor Nicholls trevor@xxxxxxxxxxxxxxxxxx
<xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> At least it's proving tricky for me...
>
>
>
> Simple case, a piece of XML which looks like this
>
>
>
> <document>
>
>   <title>document title</title>
>
>     ... (A) ...
>
>      <section>
>
>        <title>section title>
>
>        ... (B) ...
>
>     </section>
>
>   ... (C) ...
>
> </section>
>
>
>
> Assuming the current node is the <document>, I need a test which tells me
whether there is going to be any *visible* content in the space labelled (A).
>
>
>
> There are complications.
>
>
>
> Firstly, it is not sufficient to just look for a text node or img element
within (A) because a couple of elements have text content but are not rendered
by our output stage.
>
> For example, targets.
>
>
>
> <document>
>
>   <title id="a">document title</title>
>
>   <target id="b">alternative title</target>
>
>   <section>
>
>     <title id="c">section title</title>
>
>     ...
>
>   </section>
>
> </document>
>
>
>
> The number of such elements is finite, in fact off the top of my head
targets and footnotes are the only ones.
>
>
>
> Secondly, before the XSL process which needs to evaluate this test is run
the input document is pre-processed to pull in any included sub-content. These
inclusions are reflected in the document like so:
>
>
>
> <document>
>
>   <title id="a">document title</title>
>
>   <target id="b">alternative title</target>
>
>   <included srcfile="path1.xml">
>
>     <included srcfile="path1a.xml">
>
>       <section>
>
>         <title id="c">section title</title>
>
>         ...
>
>       </section>
>
>     </included>
>
>     <included srcfile="path1b.xml">
>
>       <section>
>
>         <title id="d">another section title</title>
>
>         ...
>
>       </section>
>
>     </included>
>
>   </included>
>
> </document>
>
>
>
> I need to be able to tell the difference between the case where - reading in
document order - the document contains a descendant text node (that isn't part
of the document title or a target element), or img element, before the first
section element, and the case where there isn't. I'm probably overthinking it
but after much thought I have yet to arrive at a working solution.
>
>
>
> I hope I have explained this adequately!
>
>
>
> Thanks in advance
>
> T
>
>
>
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