The pipeline
<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.0">
<p:output port="result"/>
<p:input port="source">
<doc>
<div>
<p xml:id="START1">Some para.</p>
<p>Some other para.</p>
<p xml:id="START2">One more para.</p>
</div>
</doc>
</p:input>
<p:documentation>
Note: this test relies on the fact that it's statistically unlikely that
generated ID values for any given implementation will begin with the
string ‘START'.
</p:documentation>
<p:label-elements replace="false"/>
<p:for-each>
<p:output port="result"/>
<p:with-input select="//*[@xml:id and not(starts-with(@xml:id,'START'))]"/>
<p:identity/>
</p:for-each>
<p:count/>
</p:declare-step>
Schematron validation
<s:schema xmlns:s="http://purl.oclc.org/dsdl/schematron" queryBinding="xslt2">
<s:ns uri="http://www.w3.org/ns/xproc-step" prefix="c"/>
<s:pattern>
<s:rule context="/">
<s:assert test="c:result">The document root is not c:result.</s:assert>
<s:assert test="c:result/text()='3'">Value of c:result is not '3'.</s:assert>
</s:rule>
</s:pattern>
</s:schema>
