Richard Tobin wrote:
> In article <46b22125@kcnews01>,
> Joseph Kesselman  <keshlam-nospam@c...> wrote:
> 
>>> generate-id($a) = generate-id($b) would do.
> 
>> That's definitely the simplest way to test is-same-node in XSLT 1.0.
> 
> Why is it simpler than "count($a|$b)=1" ?
> 
> I agree it may be simpler to explain.
> 
> I believe that using generate-id() is likely to be much more expensive
> in most processors, but of course this only matters when it's used
> heavily.
> 
> -- Richard
this came up a while ago on xsl-list and someone (Jeni I think) did a 
survey of popular processors and it was about 50-50 which idiom was 
quicker. On saxon at that time count() was a lot faster than using 
generate-id, so Mike changed things so saxon special cases the 
generate-id($a)=generate-id($b) idiom and rewrites it to an internal 
form which just checks same-node without actually computing the unique 
id, ie it uses an internal (for xpath1) operator equivalent to xpath 2's 
is operator. This is of course a lot faster. Though as you say, you need 
to be doing a lot of them before you can really tell the difference.

David


-- 
http://dpcarlisle.blogspot.com