Re: [xsl] CSV output - select using xpath in variable

["Imsieke, Gerrit, le-tex" <gerrit.imsieke@xxxxxxxxx>]

There are a couple of things that may go wrong: first make sure that 
$message contains proper XML.

Then instrument/isin needs to be a string (put single quotes around it):
  <xsl:variable name="path" select="'instrument/isin'" as="xs:string" />

Then it's as simple as
  <xsl:value-of select="$message/message/trade/saxon:evaluate($path)" />

Another caveat:
You declared the types of the string variables. It's a good idea to also 
declare the type of the message variable. In its current form, $message 
holds a document-node(element(message)). If you declare it
  <xsl:variable name="message" as="element(message)">
you will be able to use
  <xsl:value-of select="$message/trade/saxon:evaluate($path)" />

This is another candidate place to look for an answer to the XSLT 
developer's second-most frequently asked question: "Why doesn't my 
expression select anything?".
(This question is only a corollary to the most frequently asked 
question: "Why doesn't my template match?")

Cheers,

Gerrit

On 11.06.2010 10:02, Nick Leaton wrote:
> Thanks. I'll have a look at evaulate.
>
> At least 2.0 fixed the select from a parameter e.g.
> $message/trade/instrument and you don't have to use a node set
> function! :-)
>
> Nick
>
> On Fri, Jun 11, 2010 at 8:58 AM, Imsieke, Gerrit, le-tex
> <gerrit.imsieke@xxxxxxxxx>  wrote:
> > Dear Nick,
> >
> > dynamic evaluation of XPath expressions is not (yet?) available in standard
> > XSLT 2. Have you looked at saxon:evaluate?
> > http://www.saxonica.com/documentation/extensions/functions/evaluate.html
> >
> > Gerrit
> >
> >
> > On 11.06.2010 09:48, Nick Leaton wrote:
> > > I'm trying to get a variant on the XSLT cookbook template to output csv
> > >
> > >
> > > http://books.google.co.uk/books?id=6q50V7oykqEC&lpg=PP1&pg=PA240#v=onepage&q=delimiter&f=false
> > >
> > > Page 240-241
> > >
> > > It uses XSLT 2.0 and parts of it are quite neat.
> > >
> > > I like the idea of importing a generic module, and then defining the
> > > columns to export in the importing module.
> > >
> > > I want to extend it to hand different delimiters, in the same way, and
> > > also different line terminators.
> > >
> > > The next extension is correctly quoting the output if it containts
> > > quotes in strings etc.
> > >
> > > So far, I can do this.
> > >
> > > However, there is one problem I can't solve.
> > >
> > > My input data is not regular, but CSV output needs to be regular. So I
> > > want to defined the column names like this
> > >
> > >    <xsl:variable
> > >        name="columns"
> > >        select="
> > >        'trade',
> > >        'trade',
> > >        'currency',
> > >        'isin'
> > >        "
> > >        as="xs:string*"
> > >    />
> > >
> > > and the path names to get the data like this
> > >
> > >
> > >    <xsl:variable
> > >        name="nodepaths"
> > >        select="
> > >        'tradeid',
> > >        'trader',
> > >        'currency',
> > >        'instrument/isin'
> > >        "
> > >        as="xs:string*"
> > >    />
> > >
> > > The interesting part is the isin. To get the path from the input
> > > fragment, it is an xpath.
> > >
> > > So if I had
> > >
> > > <xsl:variable name="path" select="instrument/isin" as="xs:string"/>
> > >
> > > and
> > >
> > > <xsl:variable name="message">
> > >    <message>
> > >         <trade>
> > >               <tradeid>1</tradeid>
> > >               <trader>Nick</trader>
> > >               <currency>USD</currency>
> > >               <instrument>
> > >                      <isin>US0123456789</isin>
> > >               </instrument>
> > >           <trade>
> > >    </message>
> > > <xsl:variable>
> > >
> > > I want to do something like
> > >
> > >       <xsl:value-of select="$message/$path"/>
> > >
> > > and have it return US0123456789
> > >
> > > What's the best way?
> > >
> > > --
> > > Nick
> >
> > --
> > Gerrit Imsieke
> > Geschdftsf|hrer / Managing Director
> > le-tex publishing services GmbH
> > Weissenfelser Str. 84, 04229 Leipzig, Germany
> > Phone +49 341 355356 110, Fax +49 341 355356 510
> > gerrit.imsieke@xxxxxxxxx, http://www.le-tex.de
> >
> > Registergericht / Commercial Register: Amtsgericht Leipzig
> > Registernummer / Registration Number: HRB 24930
> >
> > Geschdftsf|hrer: Gerrit Imsieke, Svea Jelonek,
> > Thomas Schmidt, Dr. Reinhard Vvckler

--
Gerrit Imsieke
Geschdftsf|hrer / Managing Director
le-tex publishing services GmbH
Weissenfelser Str. 84, 04229 Leipzig, Germany
Phone +49 341 355356 110, Fax +49 341 355356 510
gerrit.imsieke@xxxxxxxxx, http://www.le-tex.de

Registergericht / Commercial Register: Amtsgericht Leipzig
Registernummer / Registration Number: HRB 24930

Geschdftsf|hrer: Gerrit Imsieke, Svea Jelonek,
Thomas Schmidt, Dr. Reinhard Vvckler