How do I do this in XSLT?

jerry.gadd · October 17th, 2003, 07:28 AM

I have s tricky task to do in XSLT

In my source file I have three tables
a part_list, a link_list and an entity_list as below
<?xml version="1.0" encoding="UTF-8"?>
<root>
    <part_list>
        <part>
            <id>1</id>
        </part>
        <part>
            <id>2</id>
        </part>
        <part>
            <id>3</id>
        </part>
    </part_list>
    <link_list>
        <link>
            <id>1</id>
            <parent_part>1</parent_part>
            <child_part>2</child_part>
            <mirrored>0</mirrored>
        </link>
        <link>
            <id>2</id>
            <parent_part>1</parent_part>
            <child_part>2</child_part>
            <mirrored>1</mirrored>
        </link>
        <link>
            <id>3</id>
            <parent_part>2</parent_part>
            <child_part>3</child_part>
            <mirrored>0</mirrored>
        </link>
    </link_list>
    <entity_list>
        <entity>
            <id>1</id>
            <part>3</part>
        </entity>
    </entity_list>
</root>

I transform this data into a tree as below

<?xml version="1.0" encoding="UTF-8"?>
<root>
    <part id="1" mirrored="0">
        <link id="1">
            <part id="2" mirrored="0">
                <link id="3">
                    <part id="3" mirrored="0">
                        <entity id="1" mirrored="0"/>
                    </part>
                </link>
            </part>
        </link>
        <link id="2">
            <part id="2" mirrored="1">
                <link id="3">
                    <part id="3" mirrored="1">
                        <entity id="1" mirrored="1"/>
                    </part>
                </link>
            </part>
        </link>
    </part>
</root>

using the following XSLT
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>

    <xsl:template match="/">
        <xsl:element name="root">
            <xsl:call-template name="part">
                <xsl:with-param name="part" select="//root/part_list/part[1]"/>
                <xsl:with-param name="mirrored" select="0"/>
            </xsl:call-template>
        </xsl:element>
    </xsl:template>

    <xsl:template name="part">
        <xsl:param name="part"/>
        <xsl:param name="mirrored"/>
        <xsl:variable name="id" select="$part/id"/>
        <xsl:element name="part">
            <xsl:attribute name="id"> <xsl:value-of select="$id"/></xsl:attribute>
            <xsl:attribute name="mirrored"><xsl:value-of select="$mirrored"/></xsl:attribute>
            <xsl:for-each select="//root/link_list/link[parent_part=$id]">
                <xsl:call-template name="link">
                    <xsl:with-param name="link" select="."/>
                    <xsl:with-param name="parent_mirrored" select="$mirrored"/>
                </xsl:call-template>
            </xsl:for-each>
            <xsl:for-each select="//root/entity_list/entity[part=$id]">
                <xsl:call-template name="entity">
                    <xsl:with-param name="entity" select="."/>
                    <xsl:with-param name="mirrored" select="$mirrored"/>
                </xsl:call-template>
            </xsl:for-each>
        </xsl:element >
    </xsl:template>

    <xsl:template name="link">
        <xsl:param name="link"/>
        <xsl:param name="parent_mirrored"/>
        <xsl:variable name="id" select="$link/id"/>
        <xsl:variable name="mirrored">
            <xsl:choose>
                <xsl:when test="$link/mirrored=$parent_mirrored"><xsl:value-of select="0"/></xsl:when>
                <xsl:otherwise> <xsl:value-of select="1"/></xsl:otherwise>
            </xsl:choose>
        </xsl:variable>
        <xsl:element name="link">
            <xsl:attribute name="id"> <xsl:value-of select="$id"/></xsl:attribute>
            <xsl:for-each select="//root/part_list/part[id=$link/child_part]">
                <xsl:call-template name="part">
                    <xsl:with-param name="part" select="."/>
                    <xsl:with-param name="mirrored" select="$mirrored"/>
                </xsl:call-template>
            </xsl:for-each>
        </xsl:element>
    </xsl:template>

    <xsl:template name="entity">
        <xsl:param name="entity"/>
        <xsl:param name="mirrored"/>
        <xsl:variable name="id" select="$entity/id"/>
        <xsl:element name="entity">
            <xsl:attribute name="id"><xsl:value-of select="$id"/></xsl:attribute>
            <xsl:attribute name="mirrored"><xsl:value-of select="$mirrored"/></xsl:attribute>
        </xsl:element>
    </xsl:template>

</xsl:stylesheet>

HERE IS MY PROBLEM
For every unique <entity> element (unique as regarding @id and @mirrored) I need to create a create a new table in my output like this

<?xml version="1.0" encoding="UTF-8"?>
<root>
    <part id="1" mirrored="0">
        <link id="1">
            <part id="2" mirrored="0">
                <link id="3">
                    <part id="3" mirrored="0">
                        <entity id="1" mirrored="0"/>
                    </part>
                </link>
            </part>
        </link>
        <link id="2">
            <part id="2" mirrored="1">
                <link id="3">
                    <part id="3" mirrored="1">
                        <entity id="1" mirrored="1"/>
                    </part>
                </link>
            </part>
        </link>
    </part>
    <entities>
        <entity id="1" mirrored="0"/>
        <entity id="1" mirrored="1"/>
    </entities>
</root>

It is as if I need to be able select unique node-sets from the my output so far.
How do I do this????????

jerry.gadd · October 17th, 2003, 10:44 AM

I have just solved this myself

I use the following javascript function like this each time i output a <element> element

Code:

var prototypes = new Array();
function is_new_prototype(key) {
    if (typeof prototypes[key] == "undefined") {
    prototypes[key] = 1;
    return 1;
    }
    return 0;
};

I test to see if this is the first time the element has been output
with something like the following xsl

Code:

<xsl:variable name="key" select="concat(@id, '_', @mirrored)"/>
<xsl:if test="js:is_new_element($key)">
    ....
</xsl:if>