p:run-044

The pipeline

<p:declare-step xmlns:err="http://www.w3.org/ns/xproc-error" xmlns:p="http://www.w3.org/ns/xproc" version="3.0" exclude-inline-prefixes="#all">
   <p:output port="result"/>
   <p:run>
      <p:with-input>
         <p:inline>
            <p:declare-step xmlns:fn="http://www.w3.org/2005/xpath-functions" version="3.0">
               <p:input port="source" primary="false"/>
               <p:output port="result"/>
               <p:variable name="isEmpty" collection="true" select="fn:count(fn:collection())"/>
               <p:identity>
                  <p:with-input>
                     <result>{$isEmpty}</result>
                  </p:with-input>
               </p:identity>
            </p:declare-step>
         </p:inline>
      </p:with-input>
      <p:output port="result"/>
   </p:run>
</p:declare-step>