Question

I am quite new to xsl and functional programming, so I’ll be grateful for help on this one:

I have a template that transforms some xml and provides an output. The problem is that there are many elements of type xs:date, all in different contexts, that must be localized. I use a concatenation of substrings of these xs:dates to produce a localized date pattern strings.

As you can guess this causes a lot of copy-paste “substring-this and substring-that“. How can I write a template that will automatically transform all the elements of type xs:date to localized strings preserving all the context-aware transformations?

My xsl is something like this:

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">  
    <xsl:output method="html" encoding="utf-8"/>
        <xsl:template match="/">
        ...
        <input value="{substring(/select/a/date 9,2)}.{substring(/select/a/date, 6,2)}.{substring(/select/a/date 1,4)}">
        ...
        <!-- assume that following examples are also with substrings -->
        <div><xsl:value-of select="different-path/to_date"/></div>
        ...
        <table>
        <tr><td><xsl:value-of select="path/to/another/date"/></td></tr>
        </table>
        <apply-templates/>
        </xsl:template>
        <xsl:template match="something else">
        <!-- more dates here -->
        </xsl:template>
</xsl:stylesheet>

I hope I managed to make my question clear =)

UPD: Here is an example of xml:

<REQUEST>
    <header>
        <... />
        <ref>
            <ref_date type="xs:date">1970-01-01</ref_date>
        </ref>
    </header>

    <general>
        <.../>
        <info>
            <.../>
            <date type="xs:date">1970-01-01</date>
            <ExpireDate type="xs:date">1970-01-01</ExpireDate>
            <RealDate type="xs:date">1970-01-01</RealDate>
            <templateDetails>template details</templateDetails>
            <effectiveDate type="xs:date">1970-01-01</effectiveDate>
        </info>

        <party>
            <.../>
                <date type="xs:date">1970-01-01</date>
        </party>

        <!-- many other parts of such kind -->
    </general>

</REQUEST>

As for the output, there are many different options. The main thing is that these values must be set as a value of different html objects, such as tables, input fields and so on. You can see an example in the xsl listing.

P.S. I’m using xsl 1.0.

Answer 1

What you could do is add a template to match any element which has an @type attribute of ‘xs:date’, and do you substring manipulation in there

<xsl:template match="*[@type='xs:date']">
   <xsl:value-of select="translate(., '-', '/')" />
</xsl:template>

In this case I am just replacing the hyphens by slashes as an example.

Then, instead of using xsl:value-of….

<div><xsl:value-of select="different-path/to_date"/></div>  

You could use xsl:apply-templates

<div><xsl:apply-templates select="different-path/to_date"/></div>  

Consider this XSLT as an example

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

    <xsl:template match="*[@type='xs:date']">
        <xsl:copy>
            <xsl:value-of select="translate(., '-', '/')" />
        </xsl:copy>
    </xsl:template>

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

In this case, all this XSLT is doing is copying the XML document as-is, but changing the date elements.

If you wanted to use the date template for other elements, or values, you could also make it a named-template, like so

<xsl:template match="*[@type='xs:date']" name="date">
    <xsl:param name="date" select="." />
    <xsl:value-of select="translate($date, '-', '/')" />
</xsl:template>

This would allow you to also call it much like a function. For example, to format a data and add as an attribute you could do the following:

<input>
   <xsl:attribute name="value">
       <xsl:call-template name="date">
          <xsl:with-param name="date" select="/select/a/date" />
       </xsl:call-template>
   </xsl:attribute>
</input>