Using XSL to move from one node to another

Question

So I want to convert the following using XSL

<doc>
    <data id="priority" level="2" include="true">
        <name>Priority</name>
    </data>
    <data id="cost" level="1" leveltype="number">
        <name>Cost</name>
    </data>
    <data id="date" level="3" include="true">
        <name>Date</name>
    </data>
</doc>

To this

<doc>
    <data id="priority">
        <name>Priority</name>
    </data>
    <data id="cost">
        <name>Cost</name>
    </data>
    <data id="date">
        <name>Date</name>
    </data>

    <!-- ordering matters, though if necessary I can reorder this manually via the DOM instead of XSL -->
    <levels>   
        <level id="cost" include="false" type="number"/>
        <level id="priority" include="true"/>
        <level id="date" include="true"/>
    </level>
</doc>

Basically I want to take the level attributes and make them their own thing. A huge bonus would be if there were some way to remove the level number and use the order of the node instead to represent that.

Answer 1

This is a shorter and simpler solution using only templates (no <xsl:for-each>):

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>
 <xsl:strip-space elements="*"/>

 <xsl:template match="node()|@*">
     <xsl:copy>
       <xsl:apply-templates select="node()|@*"/>
     </xsl:copy>
 </xsl:template>

 <xsl:template match="/*">
  <doc>
   <xsl:apply-templates select="*"/>
   <levels>
    <xsl:apply-templates select="data" mode="level">
     <xsl:sort select="@level" data-type="number"/>
    </xsl:apply-templates>
   </levels>
  </doc>
 </xsl:template>
 <xsl:template match="data/@*[not(name()='id')]"/>

 <xsl:template match="data" mode="level">
  <level id="{@id}" include="{boolean(@include)}">
   <xsl:if test="@leveltype">
    <xsl:attribute name="type"><xsl:value-of select="@leveltype"/></xsl:attribute>
   </xsl:if>
  </level>
 </xsl:template>
</xsl:stylesheet>

When applied on the provided XML document:

<doc>
    <data id="priority" level="2" include="true">
        <name>Priority</name>
    </data>
    <data id="cost" level="1" leveltype="number">
        <name>Cost</name>
    </data>
    <data id="date" level="3" include="true">
        <name>Date</name>
    </data>
</doc>

the wanted, correct result is produced:

<doc>
   <data id="priority">
      <name>Priority</name>
   </data>
   <data id="cost">
      <name>Cost</name>
   </data>
   <data id="date">
      <name>Date</name>
   </data>
   <levels>
      <level id="cost" include="false" type="number"/>
      <level id="priority" include="true"/>
      <level id="date" include="true"/>
   </levels>
</doc>

Explanation:

1. Using and overriding the identity rule/template.

2. Using mode="level" to generate the second part of the result-document.

Answer 2

Just a variant:

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>

<xsl:template match="doc">

 <doc>

  <!-- build and sort data nodes -->
  <xsl:for-each select="data">
   <xsl:sort select="@id"/>
    <data id="{@id}">
     <xsl:copy-of select="name"/>
    </data>
   </xsl:for-each>

   <!-- build and sort levels -->
   <levels>
    <xsl:for-each select="data">
     <xsl:sort select="@id"/>
      <level id="{@id}" include="{boolean(@include)}">
       <xsl:if test="@leveltype">
        <xsl:attribute name="type">
         <xsl:value-of select="@leveltype"/>
        </xsl:attribute>
       </xsl:if>
      </level>
    </xsl:for-each>
   </levels>

 </doc>

 </xsl:template>
</xsl:stylesheet>