Re: Style vs. Transformation

[Richard Light <richard@xxxxxxxxxxxxxxxxx>]

In message <Pine.LNX.3.95.980304194016.8095B-100000@xxxxxxxxxxxxx>, Jani
Jaakkola <jjaakkol@xxxxxxxxxxxxxx> writes

>IMHO,  Jade proves that the style language with SGML
>flow objects can have enough power and expressivity so that the
>DSSSL-transformation language isn't really needed. But i'm sure
>that not everyone will share this opininion.

Remember that the DSSSL transformation and style languages share the
same underlying 'query language' (core query language as a minimum; SDQL
if implemented in full).  In fact, the definition of the transformation
language only takes up about seven pages out of 200 in the DSSSL spec -
it relies on the underlying query language for its power.

An important aspect of transformation is the ability to navigate around
the source document from where you happen to be - the extent to which
you can do this is determined by the document query language at your
disposal.  Jade is good for transformation-while-styling precisely
because of its query language support.

However, Jade goes considerably beyond DSSSL-O in the facilities it
provides, by supporting:

the math flow objects 
lambda (including #!key) 
let, letrec, let* and named let 
quasiquotation 
node-list-first 
node-list-rest 
node-property 
sgml-parse 
children 
descendants 
attributes 
follow 
preced 
data 
select-elements 
select-by-class 
node-list-no-order 
node-list=? 
node-list? 
node-list 
node-list-map 
node-list-length 
node-list-ref 
node-list-reverse 
named-node-list? 
named-node 
named-node-list-names 
named-node-list-normalize 
process-node-list 
node-list-address (argument restricted to a singleton node-list) 
element-with-id 
empty-node-list 

Without this lot, I think that it would be hard to use Jade even for
routine styling.  So I think we should be clear as to the query language
facilities that XSL will offer us.  Surely the Jade experience shows us
that the core query language and DSSSL-O just aren't enough?

Richard Light.

Richard Light
SGML/XML and Museum Information Consultancy
richard@xxxxxxxxxxxxxxxxx


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