Collection 003

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">
   <p:output port="result">
   <p:identity name="id1">
      <p:with-input port="source">
         <p:inline>
            <doc/>
         </p:inline>
      </p:with-input>
   </p:identity>
   <p:identity name="id2">
      <p:with-input port="source">
         <p:inline>
            <doc/>
         </p:inline>
      </p:with-input>
   </p:identity>
   <p:identity name="combine">
      <p:with-input port="source" pipe="@id1 @id2">
   </p:identity>
   <p:variable name="a" select="count(collection())" collection="true">
   <p:wrap-sequence>
      <p:with-option name="wrapper" select="concat('wrapper', *[1]/name())">
      <p:with-input>
         <doc>{$a}</doc>
      </p:with-input>
   </p:wrap-sequence>
</p:declare-step>