XSLT APIs should provide the ability to set XSLT
variables before processing a stylesheet.  XT
provides this.  However, XT is a command-line
program.  In order for a web site to exhibit
decent response time, command-line
programs must be avoided.

Furthermore, you may want to set assign a large
amount of data to a variable.  
You might even want to assign a DOM to a
variable. Assigning a DOM would give 
better performance than assigning a string 
because you just might already have a DOM handy.
An extra parse can be avoided, which could
make a big difference when dealing with large
documents.

A specific need for this is the case of merging
or appending two XML documents.  document() is
a useful function as long as your
XML is accessible by a URL.  As XML development
matures, XML will be derived from databases
and APIs more and more.  With today's XSLT spec, the
only way to merge two documents without
at least one document being accessible by
a URL is to modify the stylesheet first.  As 
someone who has real experience with modifying
stylesheets on the fly in order to merge documents, 
I can tell you that:

(a) The concept is confusing
(b) It's overly cumbersome
(c) It's slow

If there is ever a push for a standard interface like the DOM
for XPATH and XSLT, and I can tell you that we
needed one about a month ago, I certainly hope that
the API enables variable assignment before
the stylesheet is processed.

Thank you,
Terris


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