XSLT lookup using regex - xslt-2.0

Question

I have a large xsl:choose (i.e. ~100) where the xsl:when is testing using a regex. I'm looking for a cleaner way, can this be replaced with a lookup table? This is just a sample of my code looks like today
<xsl:when test="matches($seq4, '^\w+-\w+-\w+-\d+/NCell:.+$', 'i')">
<xsl:value-of select="'NEIGHBOR'"/>
</xsl:when>
<xsl:when test="matches($seq4, '(/ULoCell:NodeB Function Name=.*, Local Cell ID=.*)', 'i')">
<xsl:value-of select="'SECTOR'"/>
</xsl:when>
I appreciate the help and I think I can make the Map sample code work if I make it a separate XML file and use import or include. I'm just wonder how difficult it would be to convert this into a document lookup. I'm familiar with document lookup and keys, but I have no idea how I would code the lookup using a regex? I Have the following lookup document:
<Telsa xmlns:xs="http://www.w3.org/2001/XMLSchema">
<Row Key1="^[A-Z0-9]+/Cell:eNodeB Function Name=[A-Z0-9]+, Local Cell ID=[0-9]+, Cell Name=.*/CnOperator:CnOperatorId=[0-9]+$" ElementType="CELL_CORE_OPERATOR" RegexReplace="&apos;^([A-Z0-9]+)/Cell:eNodeB Function Name=[A-Z0-9]+, Local Cell ID=([0-9]+), Cell Name=.*/CnOperator:(CnOperatorId=[0-9]+)&apos;, &apos;$1/CELL:$2/$3&apos;"></Row>
<Row Key1="^\w+-\w+-\w+-\d+/Cell:eNodeB Function Name=[A-Z0-9]+, Local Cell ID=[0-9]+, Cell Name=.*, eNodeB ID=[0-9]+, Cell.*$" ElementType="CELL" RegexReplace="&apos;^\w+-\w+-\w+-\d+/Cell:eNodeB Function Name=([A-Z0-9]+), Local Cell ID=([0-9]+), Cell Name=.*, eNodeB ID=([0-9]+), Cell.*$&apos;, &apos;$1/Cell:$2&apos;"></Row>
<Row Key1="^\w+-\w+-\w+-\d+/EthernetInterface:Ethernet Interface No.=.*$" ElementType="EthernetInterface" RegexReplace="&apos;^(\w+-\w+-\w+-\d+)/EthernetInterface:Ethernet Interface No.=([0-9]+)$&apos; , &apos;$1/No=$2&apos;"></Row>
<Row Key1="^[A-Z0-9]+/CELL:Local cell identity=[0-9]+, Cell Name=.*/OPERATOR:CnOperatorId=[0-9]+$" ElementType="CELL_CORE_OPERATOR" RegexReplace="&apos;^([A-Z0-9]+/CELL:)Local cell identity=([0-9]+), Cell Name=.*/OPERATOR:(CnOperatorId=[0-9]+)&apos; , &apos;$1$2/$3&apos;"></Row>
<Row Key1="^[A-Z0-9]+/Cell:Local cell identity=[0-9]+, Cell Name=.*, eNodeB identity=[0-9]+$" ElementType="CELL" RegexReplace="&apos;^([A-Z0-9]+/Cell:)Local cell identity=([0-9]+), Cell Name=.*, eNodeB identity=[0-9]+$&apos;, &apos;$1$2&apos;"></Row>
<Row Key1="^[A-Z0-9]+/Cell:eNodeB Function Name=[A-Z0-9]+, Local Cell ID=[0-9]+, Cell Name=.*, eNodeB ID=[0-9]+$" ElementType="CELL" RegexReplace="&apos;^([A-Z0-9]+)/Cell:eNodeB Function Name=[A-Z0-9]+, Local Cell ID=([0-9]+), Cell Name=.*, eNodeB ID=([0-9]+)$&apos;, &apos;$1/Cell:$2&apos;"></Row>
<Row Key1="^[A-Z0-9]+/Cell:eNodeB Function Name=[A-Z0-9]+, Local Cell ID=[0-9]+, Cell Name=.*, eNodeB ID=[0-9]+$" ElementType="CELL" RegexReplace="&apos;^([A-Z0-9]+)/Cell:eNodeB Function Name=[A-Z0-9]+, Local Cell ID=([0-9]+), Cell Name=.*, eNodeB ID=([0-9]+)$&apos;, &apos;$1/Cell:$2&apos;"></Row>
</Telsa>
I would define the lookup with
<xsl:key name="table-lookup" match="Row" use="#Key1"/>
<xsl:variable name="LookupDoc" select="document('Telsa.xml')/Telsa"/>
How do I code the key lookup though?
<xsl:value-of select="key('table-lookup', $curr_key, $LookupDoc)/#ElementType"/>

Answer 1

Perhaps the following is what you are looking for, it stores the regular expressions, flags, and result in an XML structure and then looks up the first matching element:
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
exclude-result-prefixes="xs"
version="2.0">
<xsl:param name="pattern-map" as="element(map)*">
<map pattern="^\w+-\w+-\w+-\d+/NCell:.+$" flags="i">NEIGHBOR</map>
<map pattern="(/ULoCell:NodeB Function Name=.*, Local Cell ID=.*)" flags="i">SECTOR</map>
</xsl:param>
<xsl:template match="#* | node()">
<xsl:copy>
<xsl:apply-templates select="#* | node()"/>
</xsl:copy>
</xsl:template>
<xsl:template match="item">
<xsl:copy>
<xsl:value-of select="$pattern-map[matches(current(), #pattern, #flags)][1]"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
When run against
<root>
<item>a-b-c-1/NCell:x</item>
<item>/ULoCell:NodeB Function Name=x, Local Cell ID=.y</item>
</root>
the output is
<root>
<item>NEIGHBOR</item>
<item>SECTOR</item>
</root>
Be careful if your regular expressions contain curly braces { or } as with a literal result element like <map pattern="\w{2}" flags="i">foo</map> this would be interpreted as an attribute value template so you would need to double them as in <map pattern="\w{{2}}" flags="i">foo</map>.

Answer 2

I like this solution, the only other question is can this logic be placed into an external document much like the lookup table?