On Thu, Jun 17, 2021 at 7:36 PM Roger L Costello costello(_at_)mitre(_dot_)org <
xsl-list-service(_at_)lists(_dot_)mulberrytech(_dot_)com> wrote:
My XML document contains a bunch of <Row> elements, like so:
<Document>
...
<Row>
<Cell>
<Data>airport</Data>
</Cell>
<Cell>
<Data>airports</Data>
</Cell>
</Row>
...
</Document>
I want to fetch the Row whose Cell[1]/Data is 'airport' and whose
Cell[2]/Data is 'airports'. So I created this XPath expression:
/Document/Row[Cell[1]/Data eq 'airport'][Cell[2]/Data eq 'airports']
I do this kind of fetching operation often, so I created a function to
fetch the desired Row:
<xsl:function name="f:getRow">
<xsl:param name="element"/>
<xsl:param name="parent"/>
<xsl:sequence select="$document/Row[Cell[1]/Data eq
$element][Cell[2]/Data eq $parent]" />
</xsl:function>
I call the function this way:
<xsl:sequence select="f:getRow('airport', 'airports')" />
Sometimes there is an element that doesn't have a parent. That is,
sometimes I'd like to fetch a Row in which Cell[2] is empty, like this:
<Row>
<Cell>
<Data>aviation</Data>
</Cell>
<Cell/>
</Row>
Then this call to f:getRow fails:
<xsl:sequence select="f:getRow('aviation', '')" /> <!-- Those are
two apostrophes within the parentheses -->
Clearly I need to modify f:getRow. I could add special case code to test
$parent to see if it is empty (the '' string) and do one thing, and if it's
not empty do another thing. But I wonder if there is a more elegant
solution that doesn't involve special case code? Is there a way to modify
the XPath expression in f:getRow such that it fetches the correct Row
regardless of whether $parent is empty or not?
Testing with XSLT 2.0. Below is an example, for the solution you may be
looking for,
XML input document,
<Document>
<Row>
<Cell>
<Data>airport</Data>
</Cell>
<Cell>
<Data>airports</Data>
</Cell>
</Row>
<Row>
<Cell>
<Data>airport</Data>
</Cell>
<Cell>
<Data>ABC</Data>
</Cell>
</Row>
<Row>
<Cell>
<Data>aviation</Data>
</Cell>
<Cell/>
</Row>
</Document>
XSLT stylesheet,
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
xmlns:f="http://test_fn";
exclude-result-prefixes="f"
version="2.0">
<xsl:output method="xml" indent="yes"/>
<xsl:variable name="document" select="/Document"/>
<xsl:template match="/">
<result>
<xsl:copy-of select="f:getRow('airport', 'airports')"/>
<xsl:copy-of select="f:getRow('aviation', '')"/>
</result>
</xsl:template>
<xsl:function name="f:getRow">
<xsl:param name="element"/>
<xsl:param name="parent"/>
<xsl:sequence select="$document/Row[Cell[1]/Data eq
$element][Cell[2]/string(Data) eq $parent]" />
</xsl:function>
</xsl:stylesheet>
The output of above XSLT transformation is following,
<?xml version="1.0" encoding="UTF-8"?>
<result>
<Row>
<Cell>
<Data>airport</Data>
</Cell>
<Cell>
<Data>airports</Data>
</Cell>
</Row>
<Row>
<Cell>
<Data>aviation</Data>
</Cell>
<Cell/>
</Row>
</result>
--
Regards,
Mukul Gandhi
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