Hi there,
I'm trying to make a tree-hierarchic document from a flat
list of elements which have id-like values which define
the hierarchy I need.
So here is simplified version of the source document:
<btc>
<record table="works">
<record table="external_records">
<field name="external_id"><value>FOO/1</value></field>
<field name="ds_name"><value>ms-sources</value></field>
</record>
<record table="external_records">
<field name="external_id"><value>FOO/1/1</value></field>
<field name="ds_name"><value>ms-sources</value></field>
</record>
<record table="external_records">
<field name="external_id"><value>FOO/1/2</value></field>
<field name="ds_name"><value>ms-sources</value></field>
</record>
<record table="external_records">
<field name="external_id"><value>FOO/2</value></field>
<field name="ds_name"><value>ms-sources</value></field>
</record>
<record table="external_records">
<field name="external_id"><value>FOO/2/1</value></field>
<field name="ds_name"><value>ms-sources</value></field>
</record>
<record table="external_records">
<field name="external_id"><value>FOO/2/1/1</value></field>
<field name="ds_name"><value>ms-sources</value></field>
</record>
<record table="external_records">
<field name="external_id"><value>FOO/2/1/2</value></field>
<field name="ds_name"><value>ms-sources</value></field>
</record>
<record table="external_records">
<field name="external_id"><value>FOO/2/2</value></field>
<field name="ds_name"><value>ms-sources</value></field>
</record>
<record table="external_records">
<field name="external_id"><value>FOO/3</value></field>
<field name="ds_name"><value>ms-sources</value></field>
</record>
</record>
</btc>
which should become this after transformation:
<ol>
<li id="FOO/1">
FOO/1
<ol>
<li id="FOO/1/1">
FOO/1/1
</li>
<li id="FOO/1/2">
FOO/1/2
</li>
</ol>
</li>
<li id="FOO/2">
FOO/2
<ol>
<li id="FOO/2/1">
FOO/2/1
<ol>
<li id="FOO/2/1/1">
FOO/2/1/1
</li>
<li id="FOO/2/1/2">
FOO/2/1/2
</li>
</ol>
</li>
<li id="FOO/1/2">
FOO/2/2
</li>
</ol>
</li>
<li id="FOO/2">
FOO/3
</li>
</ol>
So far I have the following:
<?xml version="1.0" encoding="utf-8" ?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"; version="1.0">
<xsl:output method="xml" />
<xsl:template name="count-slashes">
<!-- this template counts the number of '/' characters in a string -->
<xsl:param name="str" />
<xsl:param name="current-count" select="0" />
<xsl:choose>
<xsl:when test="contains($str, '/')">
<xsl:call-template name="count-slashes">
<xsl:with-param name="str"><xsl:value-of select="substring-after($str,
'/')" /></xsl:with-param>
<xsl:with-param name="current-count" select="number($current-count) +
1" />
</xsl:call-template>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$current-count" />
</xsl:otherwise>
</xsl:choose>
</xsl:template>
<xsl:template match="/">
<xsl:apply-templates select="//record[(_at_)table='works']" />
</xsl:template>
<xsl:template match="record[(_at_)table='works']">
<ol>
<xsl:apply-templates select="//record[(_at_)table='external_records'
and
field[(_at_)name='ds_name']/value='ms-sources']">
<xsl:with-param name="at-top-level">1</xsl:with-param>
</xsl:apply-templates>
</ol>
</xsl:template>
<xsl:template match="record[(_at_)table='external_records' and
field[(_at_)name='ds_name']/value='ms-sources']">
<xsl:param name="at-top-level" select="0" />
<xsl:variable name="id" select="field[(_at_)name='external_id']/value" />
<xsl:variable name="level"><xsl:call-template
name="count-slashes"><xsl:with-param name="str"><xsl:value-of
select="$id" /></xsl:with-param></xsl:call-template></xsl:variable>
<xsl:if test="($at-top-level='1' and number($level)=1) or ($at-top-level!='1'
and number($level)>1)">
<li id="{$id}">
<xsl:value-of select="$id" />
<!-- apply sub-records -->
<xsl:if test="count(//record[(_at_)table='external_records'
and
field[(_at_)name='ds_name']/value='ms-sources'
and
field[(_at_)name='external_id']/value!=$id
and
contains(field[(_at_)name='external_id']/value, $id)])>0">
<ol>
<xsl:apply-templates select="//record[(_at_)table='external_records'
and
field[(_at_)name='ds_name']/value='ms-sources'
and
field[(_at_)name='external_id']/value!=$id
and
contains(field[(_at_)name='external_id']/value, $id)]" />
</ol>
</xsl:if>
</li>
</xsl:if>
</xsl:template>
</xsl:stylesheet>
The basic idea is that it goes through these
record[(_at_)table="external_records"]
elements but then subverts the normal processing order by calling
<xsl:apply-templates> in the middle of the <record>-matching template selecting
any other record[(_at_)table="external_records"] which having id values which
match
the beginning of the current id value (e.g. selecting FOO/1/1 from inside
FOO/1).
Of course, XSLT will still process all the elements in document order so I've
tried to avoid it processing the, e.g., FOO/1/1 elements twice with the
condition that it may only process the element if the parameter $at-top-level
has the value "1" and the current id value is of level "1" (i.e. it has one '/'
in it) or if $at-top-level is not "1" (i.e. the template is being recusively
called) and the current id value is of a level greater than 1.
This attempt at a solution is not only protracted and incomprehensible, it
doesn't actually work either.
The elements end up being processing in document order as well as being
processed recursively. One possible solution I started on was having it find
the previous element's id and only processing the element if that previous
id is of the same or a higher level.
I got as far as attempting to select the previous record's id with this
monstrosity:
<xsl:variable name="prev-record-level-str">
<xsl:choose>
<xsl:when test="count(preceding-sibling::record)=0">0</xsl:when>
<xsl:otherwise>
<xsl:call-template name="count-slashes">
<xsl:with-param name="str">
<xsl:value-of
select="preceding-sibling::record[(_at_)table='external_records'
field[(_at_)name='ds_name']/value='ms-sources'][1]/field[(_at_)name='external_id']/value"
/>
</xsl:with-param>
</xsl:call-template>
</xsl:otherwise>
</xsl:choose>
</xsl:variable>
<xsl:variable name="prev-record-level">
<xsl:value-of select="number($prev-record-level-str)" />
</xsl:variable>
But it doesn't seem to work.
Can anyone think of a solution to this? Preferably disregarding my
existing attempt.
--
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Richard Lewis
ISMS, Computing
Goldsmiths, University of London
Tel: +44 (0)20 7078 5134
Skype: richardjlewis
JID: ironchicken(_at_)jabber(_dot_)earth(_dot_)li
http://www.richard-lewis.me.uk/
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+-------------------------------------------------------+
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+-------------------------------------------------------+
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