Strange string comparison result

[Dankwart Plattner]

Hi,
I hope this is the right group for this question. If not, please point me to right one. Some days ago I dared to put my hands on xml for the first time. I want to compare 2 string values:

1. |<xsl:value-of
select="substring-before(preceding-sibling::track[1]/title,$sepchar)"/>|<br></br>
2. |<xsl:value-of
select="substring-before(preceding-sibling::track[2]/title,$sepchar)"/>|<br></br>
3. <xsl:value-of
select="boolean(substring-before(preceding-sibling::track[1]/title,$sepchar) = substring-before(preceding-sibling::track[2]/title,$sepchar))"/><br></br>
4. <xsl:value-of
select="boolean(substring-before(preceding-sibling::track[2]/title,$sepchar) = substring-before(preceding-sibling::track[1]/title,$sepchar))"/><br></br>

where $sepchar is ":".
(1) results in |Konzert für Oboe und Orchester|
(2) results in ||
3. is true
4. is true

How could this possibly be?
Thanks for any answer in advance.

 

[Martin Honnen]

Dankwart Plattner wrote:

Some days ago I dared to put my hands on xml for the first time. I want to compare 2 string values:

1. |<xsl:value-of
select="substring-before(preceding-sibling::track[1]/title,$sepchar)"/>|<br></br>
2. |<xsl:value-of
select="substring-before(preceding-sibling::track[2]/title,$sepchar)"/>|<br></br>
3. <xsl:value-of
select="boolean(substring-before(preceding-sibling::track[1]/title,$sepchar) = substring-before(preceding-sibling::track[2]/title,$sepchar))"/><br></br>
4. <xsl:value-of
select="boolean(substring-before(preceding-sibling::track[2]/title,$sepchar) = substring-before(preceding-sibling::track[1]/title,$sepchar))"/><br></br>

where $sepchar is ":".
(1) results in |Konzert für Oboe und Orchester|
(2) results in ||
3. is true
4. is true

How could this possibly be?

Could you show us the input XML?

 

[Dankwart]

Dankwart Plattner wrote:

Some days ago I dared to put my hands on xml for the first time. I want to compare 2 string values:

1. |<xsl:value-of
select="substring-before(preceding-sibling::track[1]/title,$sepchar)"/>|<br></br>
2. |<xsl:value-of
select="substring-before(preceding-sibling::track[2]/title,$sepchar)"/>|<br></br>
3. <xsl:value-of
select="boolean(substring-before(preceding-sibling::track[1]/title,$sepchar) = substring-before(preceding-sibling::track[2]/title,$sepchar))"/><br></br>
4. <xsl:value-of
select="boolean(substring-before(preceding-sibling::track[2]/title,$sepchar) = substring-before(preceding-sibling::track[1]/title,$sepchar))"/><br></br>

where $sepchar is ":".
(1) results in |Konzert für Oboe und Orchester|
(2) results in ||
3. is true
4. is true

How could this possibly be?

Could you show us the input XML?

Thanks for your reaction.
Sure (its over 1400 lines, I stripped it to the bones, preserving the structure):

<?xml version="1.0"?>
<data>
<fld>
...snip...
</fld>
<record table="album" id="39">
<albumdata>
...snip...
</albumdata>
<trackdata items="1" sides="1">
<item>
...snip...
<side>
...snip...
<track id="452">
...snip...
<title>Toccata und Fuge d-moll BWV 565</title>
...snip...
</track>
<track id="453">
...snip...
<title>Konzert für Oboe und Orchester: Adagio
</title>
...snip...
</track>
<track id="454">
...snip...
<title>Sonate a-dur KV 331: Rondo alla Turca
a-moll</title>
...snip...
</track>
...more tracks here...
</side>
</item>
</trackdata>
</record>
</data>

My actual selected position is the track with id="454". Both substrings of the preceding-siblings are returned correctly in (1) and (2) (since the first track title has no $sepchar, the substr returns an empty string). What compells me is the result of the comparison in (3) and (4).
Thanks for your effort!

 

[Richard Tobin]

[/QUOTE]

A bug in the XPath implementation you are using?

If I apply the stylesheet below to your example (using xalan), I get the expected output

|Konzert f?r Oboe und Orchester|
||
falsefalse

--- Richard

<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<xsl:template match="*">
<xsl:apply-templates select="*"/>
</xsl:template>

<xsl:variable name="sepchar">:</xsl:variable>

<xsl:template match="track[3]">
|<xsl:value-of select="substring-before(preceding-sibling::track[1]/title,$sepchar)"/>| |<xsl:value-of select="substring-before(preceding-sibling::track[2]/title,$sepchar)"/>| <xsl:value-of select="boolean(substring-before(preceding-sibling::track[1]/title,$sepchar) = substring-before(preceding-sibling::track[2]/title,$sepchar))"/> <xsl:value-of select="boolean(substring-before(preceding-sibling::track[2]/title,$sepchar) = substring-before(preceding-sibling::track[1]/title,$sepchar))"/> </xsl:template>

</xsl:stylesheet>

 

[Dankwart]

Thanks to all contributors. It indeed seems to be a problem with the XSLT engine. Cheers Dankwart