Hi Jason,

> Not trying to accomplish any thing was just messing around and thought
that
> it might be a good way to check for the last record in a group during a
loop.
> Since I can't reassign variables and position() tells me where in a loop I
am
> and position() can also be used to specify a node to look up it seemed
(maybe
> foolishly) that this was an easy way to know if the current node and
previous
> node for a given value match.

The position() function when used **outside** a predicate will give you the
position within the currently processed node-set (e.g. that selected by a
@select on <xsl:apply-templates> or <xsl:for-each>).  When the position()
function is used **within** a predicate then it ruturns the index of the
node within the nodes selected by the XPath expression to the left of the
predicate.

Your problem remains...

>   <xsl:when test="/foo/bar[position()=position()-1]/@attrib">

read the bit inside the [] predicate! ;)

How can "position()=position()-1" ever evaluate to true???  It can't... x
can never equal (x - 1)... complete impossibility!  ;)

Maybe one of those position()'s is the position prior to the predicate?  In
which case you would need to store one to a variable first, e.g something
like...

 <xsl:for-each select="bar">
   <xsl:variable name="curr-posn" select="position()"/>
   <xsl:choose>
   <xsl:when test="/foo/bar[position()=$curr-posn -1]/@attrib">
      ...

or even just calc the index, e.g.

 <xsl:for-each select="bar">
   <xsl:variable name="prev-posn" select="position() - 1"/>
   <xsl:choose>
   <xsl:when test="/foo/bar[$prev-posn]/@attrib">
      ...

Cheers
Marrow

"Jason Burr" <JasonBurr@d...> wrote in message
news:C68421B0-71EE-4519-B453-EEB0735C5504@m......
> Hey Marrow,
>
> Not trying to accomplish any thing was just messing around and thought
that
> it might be a good way to check for the last record in a group during a
loop.
> Since I can't reassign variables and position() tells me where in a loop I
am
> and position() can also be used to specify a node to look up it seemed
(maybe
> foolishly) that this was an easy way to know if the current node and
previous
> node for a given value match. I am aware of Muenchian (you may have helped
me
> out with that).
>
> Anyway the context of that example would have been in
>
> <foo>
>   <bar attrib='test'>
>   <bar attrib='test'>
>   <bar attrib='test2'>
> </foo>
>
> <xsl:for-each select="bar">
>   <xsl:choose>
>   <xsl:when test="/foo/bar[position()=position()-1]/@attrib">
>    <xsl:value-of select="@attrib"/>
>   </xsl:when>
>   <xsl:otherwise>
>     <xsl:value-of select="@attrib"/> end of group
>   </xsl:otherwise>
>   </xsl:choose>
> </xsl:for-each>
>
> Result expected
>
> test
> test end of group
> test2
>
> Clearly I didn't mess with the keys or anything for grouping but this
would
> work if the xml was ordered or if using the Muenchian Technique. (that is
if
> it evaluated like it does when using value-of)
>
> As far as it evaluating to nothing thats not completely true becuase if I
> hard code in the value of the position
>
> <xsl:value-of select="/foo/bar[position()=3]/@attrib"/>
>
> The the result would be
>
> test2
>
> and if I do
>
> <xsl:value-of select="position()-1"/>
>
> I would get
>
> 0
> 1
> 2
>
> So my general question was why would that not evaluate to the value of the
> node (which does exist) and return the value requested. Further if there
is
> no way for this to work then is there another way to evaluate the same
thing
> (the previous node processed in a for-each)
>
> Thanks,
>
> Jason
>
>
>
> "Marrow" wrote:
>
> > Hi Jason,
> >
> > > But that this never returns a result
> > >
> > > <xsl:value-of select="/foo/bar[position()=position()-1]/@attrib"/>
> >
> > Of course it won't ever return anything...  the predicate [] expression
can
> > never evalaute to true.
> >
> > > What I want to do here is look at the last record in a loop to see if
I am
> > > at the end of a grouping (begininig of the next actually)
> >
> > Based on what you have described so far (but not seeing more of the XSLT
and
> > XML) I'd say it'is unlikely that your current method of doing grouping
will
> > work.  There are a couple of ways of doing grouping in XSLT 1.0 - the
> > Muenchian Technique and preceding-sibling technique.  I'm sure if you
post
> > an example of what your are trying to do someone will be able to show
you
> > how to do these.
> >
> > Cheers
> > Marrow
> > http://www.marrowsoft.com - home of Xselerator (XSLT IDE and debugger)
> > http://www.topxml.com/Xselerator
> >
> >
> > "Jason Burr" <JasonBurr@d...> wrote in message
> > news:3CEE074F-AD95-4124-ADD2-8DB46106D9BA@m......
> > > Can someone explain why doing this writes a number one less than the
> > current
> > > position.
> > >
> > > <xsl:value-of select="position()-1"/>
> > >
> > > Doing this will display a specific positions value
> > >
> > > <xsl:value-of select="/foo/bar[position()=3]/@attrib"/>
> > >
> > > But that this never returns a result
> > >
> > > <xsl:value-of select="/foo/bar[position()=position()-1]/@attrib"/>
> > >
> > > What I want to do here is look at the last record in a loop to see if
I am
> > > at the end of a grouping (begininig of the next actually)
> > >
> >
> >
> >