p:replace-008 (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:replace match="@a">
      <p:with-input port="source">
         <doc a="4"/>
      </p:with-input>
      <p:with-input port="replacement">
         <new-element>
            <element/>
         </new-element>
      </p:with-input>
   </p:replace>
</p:declare-step>