Re: [xsl] Practicality of Separating Data from Presentation

Subject: Re: [xsl] Practicality of Separating Data from Presentation
From: "James Fuller" <james.fuller@xxxxxxxxxx>
Date: Mon, 1 Jul 2002 20:07:49 +0100
Hello Tim,

----- Original Message -----
From: <intelikon@xxxxxxxxx>
> After reading Jeni Tennison's book 'XSLT & XPath On the Edge' I was most
interested in Part III of the book.  I understood the concepts presented
(reusing XML snippets, page templates, multiple stylesheets, etc.) but what
I am vexed about is the 'placement' of ASP code - ASP conditionals , etc.  I
came across an article on XML.com :
http://www.xml.com/pub/a/2002/03/27/templatexslt.html - which in the third
paragraph, the author says XSLT "fails miserably at separating these two
layers (data & presentation)."  My question is, does the use of ASP bring
conflict to the framework of using XML & XSLT to separate data from
presentation?  And specifically do you see or practice the placement of ASP
in the backend (in XML) or in the middle (in XSL/XSLT) or in the front
(before the presentation)?

you will find that there are people out there that *gasp* hate XSLT for many
reasons;

some qualifying statements that might help you in your quest for truth

- XQuery people think its a bit wimpy in real data situations, true but its
simplicity means it gets adopted, even people who use XML have some problems
with XSLT. The fact remains that XSLT solves most of XQueries use cases.

- SQL people say 'why' use xml and thusly xslt ; especially since the
performance aspects outstrip anything at the moment, but my only retort to
them is 'why are there not any SQL editors of worth out there'; analogy is
powerful in learning and designers, developers and regular people generally
'get' html.... even if it presents mixed processing models and gray muddy
water in serious data ( and data typing ) situations. The real issue here is
that people have spent lots of time, money and energy in to learning RDBMS
and SQL. What I dont get is that a serious architecture does not preclude
the use of RDBMS, read up on some of Oracle's, IBM, M$ approach, all of whom
have doped up their products with XML.

- XSLT is actually much better at integrating in a plethora of many
languages( PERL, PHP, ColdFusion, Python, C, C++, Java etc), then the other
way around, depends on if you put XML ( meta data and problem specific
vocabularies ) and SOA at the center of your architecture instead of a
language specific golden hammer approach to developing applications.

- it is true, if u don't design and plan your use of any language, then it
could fail miserably at seperating data and presentation, but really this
mantra is a rather old hack; yes there are powerful savings in time when
seperating data and presentation, which is powerful in any computing context
( hey the mac doesnt even have a command line....or anything under their
GUI, their operating system IS the GUI ! )...but there are much more
compelling arguments to using xml and thusly xslt in  your architecture.

- XSLT is good for some things, some rather easy things become very hard to
do in XSLT... XSLT is a very good partner to existing languages. In
addition, u can use XSLT as a preprocessor, auto generating ASP for example.
This is where XSLT is a star in auto generating code for you.

XSLT is simple and many existing editors can manipulate text based xml
XSLT is supported in just about every major language
XSLT is a good tactical data manipulation and querying language, albeit its
more XPATH thats useful then XSLT when used as a data querying mechanism
XSLT promotes templating and strong push and pull models of processing
information
XSLT in a world of xml vocabularies is needed as a tactical language to
easily transform back and forth from ( ex. WSDL to SOAP call )
XSLT brings in some well known computing algorithims to the majority of
programmers ( think LISP )
XSLT built into the browser and common client situations means we dont need
a full blown database for manipulating data, just an xml file and XSLT
processor


I could keep on going, but maybe some other people who have more exp mixing
the use of ASP and XSLT could pipe up, I would peruse www.topxml.com and
possibly www.bayes.co.uk/xml to get some ideas of how people are doing it.

good luck, jim fuller



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