a birthday serenade for Norm

ndw50.xpl

<?xml version="1.0" encoding="UTF-8"?>
<p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
  xmlns:ndw50="urn:ndw:birthday:50"
  xmlns:c="http://www.w3.org/ns/xproc-step" 
  xmlns:cx="http://xmlcalabash.com/ns/extensions"
  version="1.0"
  exclude-inline-prefixes="c cx ndw50"
  type="ndw50:serenade" name="serenade">
  
  <p:output port="serenade-lines" sequence="true">
    <p:pipe port="lines" step="finished-yet"/>
  </p:output>
  <p:output port="result" primary="true"/>
  <p:serialization port="result" indent="true" omit-xml-declaration="false"/>
  
  <p:option name="times" select="'50'"/>
  
  <p:input port="source" sequence="true" primary="true">
    <p:inline><line xmlns="http://docbook.org/ns/docbook">Happy birthday to you.</line></p:inline>
  </p:input>

  <p:split-sequence initial-only="true" test="position() = 1" name="first-line"/>

  <p:sink/>

  <p:count name="count">
    <p:input port="source">
      <p:pipe port="source" step="serenade"/>
    </p:input>
  </p:count>
  
  <p:sink/>

  <p:choose name="finished-yet">
    <p:xpath-context>
      <p:pipe port="result" step="count"/>
    </p:xpath-context>
    <p:when test="number(/*) lt number($times)">
      <p:output port="lines" sequence="true">
        <p:pipe port="serenade-lines" step="recurse"/>
      </p:output>
      <p:output port="serenade" primary="true"/>
      <ndw50:serenade name="recurse">
        <p:input port="source">
          <p:pipe port="matched" step="first-line"/>
          <p:pipe port="source" step="serenade"/>
        </p:input>
        <p:with-option name="times" select="$times"/>
      </ndw50:serenade>
    </p:when>
    <p:otherwise>
      <p:output port="lines" sequence="true"/>
      <p:output port="serenade" primary="true"/>
      <p:wrap-sequence wrapper="poetry" wrapper-namespace="http://docbook.org/ns/docbook" name="w1">
        <p:input port="source">
          <p:pipe port="source" step="serenade"/>
        </p:input>
      </p:wrap-sequence>
      <p:insert match="/*" position="last-child" name="i1">
        <p:input port="insertion">
          <p:inline><line xmlns="http://docbook.org/ns/docbook">Happy birthday dear Norman!</line></p:inline>
        </p:input>
      </p:insert>
      <p:insert match="/*" position="last-child" name="i2">
        <p:input port="insertion">
          <p:pipe port="matched" step="first-line"/>
        </p:input>
      </p:insert>
    </p:otherwise>
  </p:choose>
  
</p:declare-step>

out.xml

<?xml version="1.0" encoding="UTF-8"?>
<poetry xmlns="http://docbook.org/ns/docbook">
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday to you.</line>
   <line>Happy birthday dear Norman!</line>
   <line>Happy birthday to you.</line>
</poetry>