The pipeline
<p:declare-step xmlns:array="http://www.w3.org/2005/xpath-functions/array" xmlns:map="http://www.w3.org/2005/xpath-functions/map" xmlns:p="http://www.w3.org/ns/xproc" version="3.0">
<p:output port="result"/>
<p:json-join>
<p:with-input>
<p:inline>
<node/>
</p:inline>
<p:inline content-type="text/plain">This is a text.</p:inline>
<p:inline content-type="application/json" expand-text="false">{"json" : "value"}</p:inline>
</p:with-input>
</p:json-join>
<p:variable name="key" select="map:keys(array:get(., 3))[1]"/>
<p:identity>
<p:with-input>
<result>
<one>{array:get(.,1)}</one>
<two>{array:get(.,2)}</two>
<three key="{$key}">{map:get(array:get(., 3), $key)}</three>
</result>
</p:with-input>
</p:identity>
</p:declare-step>
Schematron validation
<s:schema xmlns:s="http://purl.oclc.org/dsdl/schematron" queryBinding="xslt2">
<s:pattern>
<s:rule context="/">
<s:assert test="result">The document node is not 'result'.</s:assert>
<s:assert test="result/one/node">Element 'one' does not have child 'node'.</s:assert>
<s:assert test="result/two/text()='This is a text.'">Text child of element 'two' is not 'This is a text.'</s:assert>
<s:assert test="result/three/@key='json'">Attribute 'key' of element 'three' is not 'json'.</s:assert>
<s:assert test="result/three/text()='value'">Text child of element 'three' is not 'value'.</s:assert>
</s:rule>
</s:pattern>
</s:schema>
