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Re: [xsl] Re: dynamic xpath from variable evaluate function is failing


Subject: Re: [xsl] Re: dynamic xpath from variable evaluate function is failing
From: Michael Kay <mike@xxxxxxxxxxxx>
Date: Mon, 22 Oct 2012 09:01:12 +0100

If you evaluate

<b test="(y=Unix) and (y=Solaris)">content</b>

as an XPath expression the result will probably be false, because it means

<b test="(child::y=child::Unix) and (child::y=child::Solaris)">content</b>

and comparing two empty sequences using "=" gives false.

However, as far as I can tell the string value of conlist will be empty, so the expression you are constructing is

$//[(y=Unix) and (y=Solaris)]

which would be a syntax error.

You would make your life a lot easier if the expressions in the conditions file used XPath syntax, that is, quotes around the values.

Michael Kay
Saxonica




On 22/10/2012 06:41, M Balaji wrote:
I need to construct the dynamic XPATH predicate from the input XML. I tried
with evaluate function, but  its not converting the String to XPATH
predicate. Can any one let me know how can I achieve this?

Input: test.xml

<a>

<b test="(x=Windows)">content</b>

<b test="(z=Unix)">content</b>

<b test="(y=Unix) and (y=Solaris)">content</b>

<b test="(z=Unix) and (y=Windows7)">content</b>

</a>

Configuration/condition evaluation file (config.xml)

<root>

<condition name="x" value="Windows8"/>

<condition name="z" value="Unix"/>

<condition name="y" value="Solaris"/>

<condition name="y" value="Windows7"/>

</root>

XSLT: test.xsl

<xsl:variable name="conlist"><s><xsl:for-each
select="document('config.xml')// condition"><xsl:element
name="{@name}">test</xsl:element><xsl:element
name="{@value}">test</xsl:element></xsl:for-each></s></xsl:variable>

<xsl:template match="*[@test]">

<xsl:param name="t" select="concat('$', conlist,'//s','[',@test,']')"/>



<xsl:if test='saxon:evaluate("$p1",$t)'>

<xsl:copy-of select="."/>

</xsl:if>



</xsl:template>


Result:


I'm getting true for all above <b> elements

Expected result:

1st and 3rd <b> should not printed in the output (condition is failing)


Thanks in Advance,


Balaji. M


On Mon, Oct 22, 2012 at 11:04 AM, M Balaji <msbalaji82@xxxxxxxxx> wrote:
I need to construct the dynamic XPATH predicate from the input XML. I tried
with evaluate function, but  its not converting the String to XPATH
predicate. Can any one let me know how can I achieve this?

Input: test.xml

<a>

<b test=3D=94(x=3DWindows)=94>content</b>

<b test=3D=94(z=3DUnix)=94>content</b>

<b test=3D=94(y=3DUnix) and (y=3DSolaris)=94>content</b>

<b test=3D=94(z=3DUnix) and (y=3DWindows7)=94>content</b>

</a>

Configuration/condition evaluation file (config.xml)

<root>

<condition name=3D=94x=94 value=3D=94Windows8=94/>

<condition name=3D=94z=94 value=3D=94Unix=94/>

<condition name=3D=94y=94 value=3D=94Solaris=94/>

<condition name=3D=94y=94 value=3D=94Windows7=94/>

</root>

XSLT: test.xsl

<xsl:variable name=3D"conlist"><s><xsl:for-each
select=3D"document('config.xml')// condition"><xsl:element
name=3D"{@name}">test</xsl:element><xsl:element
name=3D"{@value}">test</xsl:element></xsl:for-each></s></xsl:variable>

<xsl:template match=3D=94*[@test]=94>

<xsl:param name=3D"t" select=3D"concat('$', conlist,'//s','[',@test,']')"/>



<xsl:if test=3D'saxon:evaluate("$p1",$t)'>

<xsl:copy-of select=3D"."/>

</xsl:if>



</xsl:template>


Result:


I'm getting true for all above <b> elements

Expected result:

1st and 3rd <b> should not printed in the output (condition is failing)


Thanks in Advance,


Balaji. M


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