xpath preceding-sibling problem

Unicorn · August 21st, 2012, 12:39 PM

Hello,

i'm trying to produce this "get the fisrt preceding sibling (looking backwards) that meets the condition"

e.g.

XML

Code:

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type='text/xsl' href='test.xsl'?>
<chars>
	<char type="letter">A</char>
	<char type="letter">B</char>
	<char type="letter">C</char>
	<char type="letter">D</char>
	<char type="digit">1</char>
	<char type="digit">2</char>
	<char type="digit">3</char>
	<char type="digit">4</char>
	<char type="">5</char>
</chars>

XSL

if an element has @type='', then output ( + @type of the first backwards preceding sibling that has @type!='' + )

desired output: CHARACTERS: letter A B C D digit 1 2 3 4 (digit) 5

result: CHARACTERS: letter A B C D digit 1 2 3 4 (letter) 5

Code:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
    <xsl:template match="chars" name="chars">
        <xsl:text>CHARACTERS: </xsl:text>
        <xsl:apply-templates/>
    </xsl:template>
    <xsl:template match="char" name="char">
        <xsl:variable name="previous_charType">
            <xsl:value-of select="./preceding-sibling::*[1]/@type"/>
        </xsl:variable>
        <xsl:variable name="x">
            <xsl:value-of select="./@type"/>
        </xsl:variable>
        <xsl:if test="$previous_charType != $x ">
            <xsl:text> </xsl:text>
            <b>
                <xsl:value-of select="$x"/>
            </b>
        </xsl:if>
        <xsl:if test="./@type=''">
            <xsl:text>(</xsl:text>
            <xsl:value-of select="preceding-sibling::*[@type!='']/@type"/>
            <xsl:text>) </xsl:text>
        </xsl:if>
        <xsl:text> </xsl:text>
        <xsl:value-of select="."/>
        <xsl:text> </xsl:text>
    </xsl:template>
</xsl:stylesheet>

Any ideas? the <xsl:value-of select="preceding-sibling::*[@type!='']/@type"/> doen't work...

Thank You

Martin Honnen · August 21st, 2012, 01:00 PM

I think the main issue is to use a positional predicate [1] e.g.

Code:

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
    <xsl:output method="html"/>
    <xsl:template match="chars">
        <xsl:text>CHARACTERS: </xsl:text>
        <xsl:apply-templates/>
    </xsl:template>
    <xsl:template match="char">
        <xsl:variable name="previous_charType" select="preceding-sibling::*[1]/@type"/>
        <xsl:variable name="x" select="./@type"/>
        <xsl:if test="$previous_charType != $x ">
            <xsl:text> </xsl:text>
            <b>
                <xsl:value-of select="$x"/>
            </b>
        </xsl:if>
        <xsl:if test="./@type=''">
            <xsl:text>(</xsl:text>
            <xsl:value-of select="preceding-sibling::*[@type!=''][1]/@type"/>
            <xsl:text>) </xsl:text>
        </xsl:if>
        <xsl:text> </xsl:text>
        <xsl:value-of select="."/>
        <xsl:text> </xsl:text>
    </xsl:template>
</xsl:stylesheet>

Unicorn · August 21st, 2012, 01:16 PM

Quote:

Originally Posted by Martin Honnen

I think the main issue is to use a positional predicate [1] e.g.

Thanks for your reply but that won't work either. The above example could actually be

Code:

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type='text/xsl' href='test.xsl'?>
<chars>
	<char type="letter">A</char>
	<char type="letter">B</char>
	<char type="letter">C</char>
	<char type="letter">D</char>
	<char type="digit">1</char>
	<char type="digit">2</char>
	<char type="digit">3</char>
	<char type="">4</char>
	<char type="">5</char>
</chars>

desired output: CHARACTERS: letter A B C D digit 1 2 3 (digit) 4 (digit) 5

result: CHARACTERS: letter A B C D digit 1 2 3 (digit) 4 () 5
or

Code:

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type='text/xsl' href='test.xsl'?>
<chars>
	<char type="letter">A</char>
	<char type="letter">B</char>
	<char type="letter">C</char>
	<char type="letter">D</char>
	<char type="digit">1</char>
	<char type="">2</char>
	<char type="">3</char>
	<char type="digit">4</char>
	<char type="digit">5</char>
</chars>

desired output: CHARACTERS: letter A B C D digit 1 (digit) 2 (digit) 3 4 5

result: CHARACTERS: letter A B C D digit 1 (digit) 2 () 3 4 5

predicate [1] works only for the first case and it's not flexible...