p:xquery 027 (AB)

The pipeline

<p:declare-step xmlns:err="http://www.w3.org/ns/xproc-error"
                xmlns:p="http://www.w3.org/ns/xproc"
                xmlns:t="http://xproc.org/ns/testsuite/3.0" version="3.0">
   <p:output port="result"/>
   <p:xquery version="3.0">
      <p:with-input port="source">
         <p:inline content-type="application/json">{{"key" : "value"}}</p:inline>
      </p:with-input>
      <p:with-input port="query">
         <p:inline content-type="text/plain">
                  declare namespace map="http://www.w3.org/2005/xpath-functions/map";
                  <result>{{map:get(., 'key')}}</result>
               </p:inline>
      </p:with-input>
   </p:xquery>
</p:declare-step>