Dimitre wrote:
>  While your mapping operator will perform a series of
>  mappings, each producing an
>  intermediate sequence and may require too much memory, the
>  last function applies the
>  map function only once. The composition of all functions is
>  applied on every element
>  of $sequence and the resulting sequence is produced. No
>  additional memory for
>  intermediate sequences is necessary.
> 
>  This shows that it is better to have a map() function and a
>  composition operator for
>  expressions (in case XPath 2.0 will not fully support
>  higher-order functions).
> 
As a point of information, the implementation of "for" expressions in Saxon
7.0 is fully pipelined, so there will never be a need to store intermediate
sequences in memory.

Mike Kay


 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list