How to read comments from XML using xslt and adding comments text in a element

Question

I am using XSLT and XML.

I have got below XML with me.

<?xml version="1.0" encoding="UTF-8"?>
<mappings>
    <!-- News mapping -->
    <mapping old="mbp" new="/SessionHandler.aspx?pageurl=/BP.aspx&amp;pub=/english&amp;section=IBE&amp;j=f"/>
    <mapping old="about/news" new="about/news/news.aspx"/>
    <!-- CUGO's-->
    <mapping old="/nhs" new="/cugo.aspx?promoCode=UKNHS01&amp;pub=/uk/english"/>
    <mapping old="/hk/ukstudentfare" new="/cugo.aspx?promoCode=HKSTU10&amp;pub=/hk/Chinese"/>   
    <!-- Reserved below vanity URL's -->
    <mapping old="/kgfmastercard" new=""/>
    <mapping old="/mastercard" new=""/>
    <!-- Other vanity URL's-->
    <mapping old="/destinationbriefs" new="http://www.ekgroup.com/destinationbriefs"/>
    <mapping old="/win" new="/ch/german/destinations_offers/win_two_tickets_on_A380.aspx"/>
    <!--FIFA Fan Fest-->
    <mapping old="/romefanfest" new="/it/italian/destinations_offers/rome_international_fifa_fan_fest.aspx"/>
    <mapping old="/parisfanfest" new="/fr/french/destinations_offers/paris_international_fifa_fan_fest.aspx"/>  
</mappings>

Below is the xslt I am using

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:fo="http://www.w3.org/1999/XSL/Format" exclude-result-prefixes="xsl fo">
  <xsl:output method="xml" indent="yes" />
  <xsl:template match="/">
    <xsl:for-each select="mappings/mapping">
      <VanityUrl>
        <old>
          <xsl:value-of select="@old" />
        </old>
        <new>
          <xsl:value-of select="@new" />
        </new>
        <dateAdded>2010-05-03T14:45:00</dateAdded>
        <xsl:if test="@new = ''">
          <NotLive>Yes</NotLive>
        </xsl:if>
        <xsl:if test="preceding-sibling::comment()">
          <comments>
            <xsl:value-of select="preceding-sibling::comment()" />
          </comments>
        </xsl:if>
      </VanityUrl>
    </xsl:for-each>
  </xsl:template>
</xsl:stylesheet>

Now what I am trying to get result like below:

<VanityUrl>
        <old>/mbp</old>
        <new>/SessionHandler.aspx?pageurl=/BP.aspx&amp;pub=/english&amp;section=IBE&amp;j=f</new>
        <dateAdded>2010-05-03T14:45:00 </dateAdded> 
        <comment>News mapping</comments>        
</VanityUrl>
<VanityUrl>
        <old>about/news</old>
        <new>about/news/news.aspx</new>
        <dateAdded>2010-05-03T14:45:00 </dateAdded> 
        <comment>News mapping</comments>        
</VanityUrl>
<VanityUrl>
        <old>/nhs</old>
        <new>/cugo.aspx?promoCode=UKNHS01&amp;pub=/uk/english</new>
        <dateAdded>2010-05-03T14:45:00 </dateAdded> 
        <comment>CUGO's</comments>      
</VanityUrl>
<VanityUrl>
        <old>/hk/ukstudentfare</old>
        <new>/cugo.aspx?promoCode=HKSTU10&amp;pub=/hk/Chinese</new> 
        <dateAdded>2010-05-03T14:45:00 </dateAdded> 
        <comment>CUGO's</comments>      
</VanityUrl>
<VanityUrl>
        <old>/kgfmastercard</old>
        <new></new>
        <NotLive>yes</NotLive>
        <dateAdded>2010-05-03T14:45:00 </dateAdded> 
        <comment>Reserved below vanity URL's</comments>     
</VanityUrl>
<VanityUrl>
        <old>/mastercard</old>
        <new></new>
        <NotLive>yes</NotLive>
        <dateAdded>2010-05-03T14:45:00 </dateAdded> 
        <comment>Reserved below vanity URL's</comments>     
</VanityUrl>

Everything is ok, but I am not able to work with comments section, how can I add the comments elements according to there related comments. I mean below code in my xslt is not working properly, its adding first comment only i.e. News mapping

xsl:if test="preceding-sibling::comment()">
              <comments>
                <xsl:value-of select="preceding-sibling::comment()" />
              </comments>
            </xsl:if>

Answer 1

preceding-sibling::comment() gives you a node-set of all preceding comment nodes on the current level in reverse document order. However, you need to pick the closest comment to make it work:

<xsl:if test="preceding-sibling::comment()[1]">
  <comments>
    <xsl:value-of select="preceding-sibling::comment()[1]" />
  </comments>
</xsl:if>