XSLT 1.0 how increment a date - xslt

Question

UPDATE: Cannot use any EXSLT extensions.
Also I'm using date in two different places and I only want to update one of them and not both.
I need to increment a date in my XSLT transformation. I'm using XSLT 1.0.
In source XML I have a date like this
<XML>
<Date>4/22/2011 3:30:43 PM</Date>
</XML>
Then I need to add 10 years to the output. Like this
<Output>
<Odate>4/22/2011 3:30:43 PM</Odate>
<Cdate>4/22/2021 3:30:43 PM</Cdate>
</Output>
How this can be done in XSLT 1.0. Thanks in advance.

Answer 1

The following is no general date arithmetic implementation but might suffice to increment the year part:
<xsl:stylesheet
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="1.0">
<xsl:param name="year-inc" select="10"/>
<xsl:template match="XML">
<Output>
<xsl:apply-templates/>
</Output>
</xsl:template>
<xsl:template match="Date">
<xsl:variable name="d0" select="substring-before(., '/')"/>
<xsl:variable name="d1" select="substring-before(substring-after(., '/'), '/')"/>
<xsl:variable name="d2" select="substring-after(substring-after(., '/'), '/')"/>
<xsl:variable name="new-year" select="substring($d2, 1, 4) + $year-inc"/>
<Cdate>
<xsl:value-of select="concat($d0, '/', $d1, '/', $new-year, substring($d2, 5))"/>
</Cdate>
</xsl:template>
</xsl:stylesheet>

Answer 2

Depends a little how pernickety you want to be, e.g. what's the date 10 years after 29 Feb 2004? There are a number of useful XSLT 1.0 date-handling routines you can download at www.exslt.org, I think they include both a parse-date template which will convert your US-format date into a standard ISO date, date arithmetic templates which will allow you to add a duration to an ISO-format date, and a format-date function that will turn it back into US format.

Answer 3

I have figured it with the help of #Martin. I extend on #Martin's code and only called the template when I need to modify the date.
XSLT:
<xsl:stylesheet
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="1.0">
<xsl:output method="xml" indent="yes"/>
<xsl:param name="year-inc" select="10"/>
<xsl:template match="XML">
<Output>
<Odate>
<xsl:value-of select="Date"/>
</Odate>
<Cdate>
<xsl:call-template name="increment"/>
</Cdate>
</Output>
</xsl:template>
<xsl:template name="increment">
<xsl:variable name="d0" select="substring-before(Date, '/')"/>
<xsl:variable name="d1" select="substring-before(substring-after(Date, '/'), '/')"/>
<xsl:variable name="d2" select="substring-after(substring-after(Date, '/'), '/')"/>
<xsl:variable name="new-year" select="substring($d2, 1, 4) + $year-inc"/>
<xsl:value-of select="concat($d0, '/', $d1, '/', $new-year, substring($d2, 5))"/>
</xsl:template>
</xsl:stylesheet>
Output:
<?xml version="1.0" encoding="utf-8"?>
<Output>
<Odate>4/22/2011 3:30:43 PM</Odate>
<Cdate>4/22/2021 3:30:43 PM</Cdate>
</Output>