[exprla-devel] RE: [XPL] Re: The structure of classes in XPL

[reid_spencer <ras...@re...>]

--- In xpl-dev@y..., "Richard Anthony Hein" <935551@i...> wrote:

-----Original Message-----
From: Garreth Galligan [mailto:garreth.galligan@o...]
Sent: June 19, 2000 11:45 AM
To: xpl@e...
Subject: [XPL] Re: The structure of classes in XPL


Richard Anthony Hein wrote:

 >XPL doesn't need classes, but to make people comfortable we
 >can make them using XPointer

This is fascinating, but I'm afraid I'm not too up to speed with
XPointer. Do you know of any good reference material? W3C
documentation is a slow, tedious read.

Not really at this point Gareth, I will look around though.  My 
comment is
probably not a good one anyways.  I meant it in the sense that you can
reference XML document nodes and fragments of nodes at any location, 
using
XPath, and use XPointer to pick out the text/values of the nodes.  
So, from
one XPL program we could make a reference to another, including that
reference as if it were a class, and add our sub-class nodes to the 
mix
without having to hand-code the superclass - the XML document that we
reference.  It doesn't seem to make sense to me to use classes in the 
sense
people are used to.  XPL should be able to allow people to mix 
together all
kinds of XPL programs and XML documents, using XPath and XPointer.  
What's
the sense in defining classes in the traditional sense?  Really, it 
would be
more like merging different sources together to build a new class, 
that can
be defined as a sub-class or super-class.

I hope I haven't confused you even more ....  Well, I am not the best 
person
for this anyways ... anyone with strong experience in OOP and a good
overview of the XML related stuff would be a better person to go by.

I have been doing a crash overview of various OOP languages and 
languages in
general, and something like BETA, which uses "patterns" may be 
something
more fitting to the structure of classes in XPL.  I am not sure, but 
it's
something to consider.  We surely need to break away from Java and 
C++,
however, if we want to really get an overview of what can be done, 
since
these two don't really fit XPL in the ways we envision.

BETA is a language that is different from Java and C++, but close 
enough to
be understandable by people experienced with those two.  Another is 
Prolog
because Prolog and like languages are fitting for a distributed DATA 
model,
with programs that are "free-ranging".  For a better understanding of 
what I
mean, take a look at Edd Dumbill's article at www.xml.com, on 
the "State of
XML", where he goes into a lot of ideas about XML being used  in a 
form of
data cloud and programs (the XPL-Fog!) roam the web accessing data in 
XML
via URIs.  These ideas echo the ideas expressed by Jonathan, Kurt, and
myself in our WorldOS postings.

This all may be seem like side-tracking the issue, but really, to be 
able to
use classes we need to get a grip on how classes might be defined in 
XML, so
I think it's not a waste of time.

Richard A. Hein





To unsubscribe from this group, send an email to:
xpl-unsubscribe@o...
--- End forwarded message ---