Re: xslt extensions - whats it about?

Hello Peter,

----- Original Message -----
From: "peter gibbons" <peter_gibbons@xxxxxxxxxxx>
Subject:  xslt extensions - whats it about?


> Hello there,
> I'm using sabcmd as my xslt engine.  I'm interested in finding out the
best
> use for extensions, i.e. when should I be using them?
>
> for instance if I wanted a timestamp from an operating system - could I
> retrieve it from an extension, is this a typical use for an extension.

this is a good characterisation of a function, remember that in the XSLT
world bringing in functionality that causes side effects is considered bad
form; a side effect could be a function that writes a file to disk, and
encounters a problem with the hard drive being full, etc.....

most XSLT processors have a way of programmatically extending it, including
built in functions that are usually binded to a namespace.

unfortunately sabcmd has little in the way of extensions, until recently

http://www.gingerall.com/charlie/ga/act/gadoc.act?pg=sablot#i__797

which means one can now use javascript within sabcmd, there are many EXSLT
function implementations using javascript at www.exslt.org, which u can now
use in conjunction with latest version of sabcmd.

remember a function could be written either within another programmatic
language, which requires an interface of some kind, or in native XSLT ( to
some extent in XSLT 1.0 with named templates).

either the XSLT processor will have an API ( in c, c++ or java ) that allows
for new functions, not to mention that one could create named templates that
act like functions ( well sort of, but with the new XSLT 2.0 draft this is
much more rigorous, of which only the experimental SAXON7 XSLT processor
implements ).

there is no common API agreed upon as of yet of how to bind functions
written into various languages within XSLT, at the moment the XSLT 2.0
draft, though within some of the java processors the java language
http://saxon.sourceforge.net/saxon7.0/extensibility.html is a nice overview.

if u want to do anything with sablotron look here
http://www.gingerall.org/ga/html/jsdom-ref/complete-frameset.html

i use sablotron quite often as it is speedy and a good core implementation
of XSLT and XPATH, but for more experimental purposes, especially with
extending the core functionality i would suggest tinkering around with
either SAXON or the APACHE effort.

good luck, jim fuller






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