Re: [xsl] Dynamic XPath expression (I know it doesnt work in XSLT1.0)

[Matt Dittbenner <mbditt@xxxxxxxxxxxxxxxxx>]

Michael Kay wrote:

> > After some pretty exhaustive searching on the web, I have decided to 
> > join the list. I have noticed in the archives that more than 
> > one person 
> > has had the same issue as I have...how to create an XPath expression 
> > dynamically (from a variable, etc). The answer to these 
> > questions was to 
> > use any of the available *:evaluate functions. I would like to try to 
> > avoid that, since it increases the parse time so much....and 
> > that is not 
> > acceptable.
> >
> > My question is if there is any other way to accomplish this, 
> > for example using XSLT2.0. 
> >    
>
>  
Thanks for the really fast reply! :)

> Sorry, but this is one feature that we decided not to put in XSLT 2.0. The
> only choices are really:
>
> (a) using an xx:evaluate() extension function
> (b) modifying the stylesheet before you execute it
>
> I'm not sure why you think there is a performance problem with the extension
> function approach?
>
>  
I don't remember where I had read it, but in some documentation somewhere...
More importantly, some tests (admittedly, not professional benchmarks or 
anything...plus the tests were run in xsltproc) showed that a very 
simple xsl stylesheet and xml input file would take an average of about 
3 seconds when not using the EXSLT dyn:evaluate function, but when using 
the function in the manner required the  average was around 6 seconds. 
Our concern was that this amount of time will increase with the 
complexity of the documents, and a 6 second parse time seems a bit 
excessive. Maybe it is faster with your implementation (?)...if you have 
any ideas to speed it up, I am open...because the only reason I'm not 
excited about it is the speed concern.

> Michael Kay