cmdline-006

The pipeline

<p:declare-step xmlns:p="http://www.w3.org/ns/xproc" xmlns:xs="http://www.w3.org/2001/XMLSchema" version="3.0" name="main">
   <p:output port="result" primary="true"/>
   <p:output port="alternate" pipe="@alt"/>
   <p:identity name="alt">
      <p:with-input>
         <doc>alternate</doc>
      </p:with-input>
   </p:identity>
   <p:identity>
      <p:with-input>
         <doc>primary</doc>
      </p:with-input>
   </p:identity>
</p:declare-step>