The pipeline
<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" version="3.0">
<p:output port="result"/>
<p:viewport match="para" name="viewport">
<p:with-input>
<doc>
<para>Some paragraph.</para>
<para>Some paragraph.</para>
<para>Some paragraph.</para>
<para>
<para>Nested paragraph.</para>
</para>
</doc>
</p:with-input>
<p:output port="tmp" sequence="true">
<p:inline>
<foo/>
</p:inline>
<p:pipe step="identity1" port="result"/>
</p:output>
<p:identity name="identity1">
<p:with-input port="source">
<p:inline>
<bar/>
</p:inline>
</p:with-input>
</p:identity>
<p:identity name="identity2">
<p:with-input port="source">
<p:inline>
<baz/>
</p:inline>
</p:with-input>
</p:identity>
<p:sink/>
</p:viewport>
</p:declare-step>
Schematron validation
<s:schema xmlns="http://www.w3.org/1999/xhtml" xmlns:s="http://purl.oclc.org/dsdl/schematron" queryBinding="xslt2">
<s:pattern>
<s:rule context="/">
<s:assert test="doc">The document root is not 'doc'.</s:assert>
<s:assert test="doc/*[1]/name()='foo'">First child is not 'foo'.</s:assert>
<s:assert test="doc/*[2]/name()='bar'">Second child is not 'bar'.</s:assert>
<s:assert test="doc/*[3]/name()='foo'">Third child is not 'foo'.</s:assert>
<s:assert test="doc/*[4]/name()='bar'">Fourth child is not 'bar'.</s:assert>
<s:assert test="doc/*[5]/name()='foo'">Fifth child is not 'foo'.</s:assert>
<s:assert test="doc/*[6]/name()='bar'">Sixth child is not 'bar'.</s:assert>
<s:assert test="doc/*[7]/name()='foo'">Seventh child is not 'foo'.</s:assert>
<s:assert test="doc/*[8]/name()='bar'">Eighth child is not 'bar'.</s:assert>
</s:rule>
</s:pattern>
</s:schema>
