test="preceding-sibling::node()[1][self::processing-instruction(xm-insertion
_mark_start)]"

Michael Kay
http://www.saxonica.com/ 

> -----Original Message-----
> From: Nadia.Swaby@xxxxxx [mailto:Nadia.Swaby@xxxxxx] 
> Sent: 02 December 2005 20:47
> To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> Subject:  How to find out if the preceding sibling is a PI
> 
> Hi all,
> 
> I have a document that looks something like this:
> 
> <?xm-insertion_mark_start author="Nadia Swaby"
> time="20051202T111856-0500"?>
> <design.consideration></design.consideration>
> 
> I need to do a test to find out if the sibling immediately 
> preceding the
> design.consideration element is an xm-insertion_mark_start PI.
> 
> Basically, I need something like
> preceding-sibling::*[position() = 1 and
> processing-instruction('xm-insertion_mark_start')]
> but that statement doesn't return anything.
> 
> Is there any way of doing this?
> 
> Thanks
> 
> Nadia