XSLT: Regular Expression function does not work?

Question

Ok, this one has been driving me up the wall...

I have a xslt function that is supposed to split out the Zip-code part from a Zip+City string depending on the country. I cannot get it to work! This is what I got so far:

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:exslt="http://exslt.org/functions" xmlns:xs="http://www.w3.org/2001/XMLSchema"&gt;
<xsl:function name="exslt:GetZip" as="xs:string">
    <xsl:param name="zipandcity" as="xs:string"/>
    <xsl:param name="countrycode" as="xs:string"/>
    <xsl:choose>
        <xsl:when test="$countrycode='DK'">
            <xsl:analyze-string select="$zipandcity" regex="(\d{4}) ([A-Za-zÆØÅæøå]{3,24})">
                <xsl:matching-substring>
                    <xsl:value-of select="regex-group(1)"/>
                </xsl:matching-substring>
                <xsl:non-matching-substring>    
                        <xsl:text>fail</xsl:text>
                </xsl:non-matching-substring> 
            </xsl:analyze-string>               
        </xsl:when>
        <xsl:otherwise>
            <xsl:text>error</xsl:text>
        </xsl:otherwise>
    </xsl:choose>
</xsl:function>

I am running it on a source XML where the following values are passed to the function:

• zipandcity: "DK-2640 København SV"
• countrycode: "DK"

...will output 'fail'!

I think there is something I am misunderstanding here...

Answer 1

Regular expressions are only supported in XSLT 2.x -- not in XSLT 1.0.

Answer 2

The regex attribute is parsed as an attribute value template whery curly braces have a special meaning. If this is in fact an XSL 2.0 Stylesheet, you need to escape the curly braces in the regex attribute by doubling them: (\d{{4}}) ([A-Za-zÆØÅæøå]{{3,24}})

Alternatively you could define a variable containing your pattern like this:

<xsl:variable name="pattern">(\d{4}) ([A-Za-zÆØÅæøå]{3,24})</xsl:variable
<xsl:analyze-string select="$zipandcity" regex="{$pattern}">

Answer 3

Aside from that facts that regexes aren't supported until XSLT 2.0 and braces have to be escaped (but backslashes don't), there's one more reason why that code won't work: XSLT regexes are implicitly anchored at both ends. Given the string DK-2640 København SV, your regex only matches 2640 København, so you need to "pad" it to make it consume the whole string:

regex=".*(\d{{4}}) ([A-Za-zÆØÅæøå]{{3,24}}).*"

.* is probably sufficient in this case, but sometimes you have to be more specific. For example, if there's more than one place where \d{4} could match, you might use \D* at the beginning to make sure the first capturing group matches the first bunch of digits.