Re: [xsl] Evaluate string as XPATH axis in XSLT1.0?

[Matt Poff <matt.poff@xxxxxxxxxxxxxxx>]

Great thanks, as I'm using the EXSLT library elsewhere in the transform 
I found the dyn:evaluate() function. The problem now is my XPATH string 
contains apostrophes which I can't seem to escape adequately for 
dyn:evaluate() to not throw errors.

The string is of the form:

./foo[@type = 'bar']

I've tried the following XSLT char escaping options expressions:

[One]
<xsl:variable name="testmap" select="dyn:evaluate('./foo[@type = 'bar']')"/>

Result: Error = "expected ")", found "<name>"

[Two]
<xsl:variable name="testmap" select="dyn:evaluate('./foo[@type = 
&apos;bar&apos;]')"/>

Result: Error = "expected ")", found "<name>"



[Three]
<xsl:variable name="testmap" select="dyn:evaluate('./foo[@type = 
\\&apos;bar\\&apos;]')"/>

Result: Error = "expected ")", found "<name>"



[Four]
<xsl:variable name="x">'</xsl:variable>
<xsl:variable name="testmap" select="dyn:evaluate(concat('./foo[@type = 
',$x, 'bar',$x,']'))"/>

Result: Parses OK but value is empty.

If I reference this path directly without using evaluate, the correct 
node-set is returned. It seems like dyn:evaluate isn't handling embedded 
apostrophes but I couldn't Google any workarounds for it.

Matt



Michael Kay wrote:
> There's no standard way to construct an XPath expression from a string at
> run-time in either XSLT 1.0 or 2.0. 
>
> Some products have an extension to do this, for example saxon:evaluate().
>
> If you want a portable solution, the only way around it is to generate a
> stylesheet.
>
> Michael Kay
> http://www.saxonica.com/ 
>
>   
> > -----Original Message-----
> > From: Matt Poff [mailto:matt.poff@xxxxxxxxxxxxxxx] 
> > Sent: 20 August 2007 06:58
> > To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> > Subject: [xsl] Evaluate string as XPATH axis in XSLT1.0?
> >
> > Hi,
> >
> > I'm trying to resolve a node attribute which contains an 
> > XPATH fragment to actually resolve that path to a value. Is 
> > this possible.
> >
> > XML with attribute looks like...
> >
> >     <grid-map map="./foo[@bar]/select" />
> >
> >
> > XSLT looks like...
> > <xsl:variable name="path" select="../grid/grid-map[1]/@map"/>
> > <xsl:value-of select="{$path}" />
> >
> > Unfortunately, this results in errors... Any ideas?
> >
> > Thanks in advance,
> > Matt