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Re: Choreography and REST

From: bhaugen <linkage@interaccess.com>
Date: Fri, 09 Aug 2002 13:45:52 -0500
To: www-ws-arch@w3.org
Message-id: <008b01c23fd4$fce6dc80$b8eafea9@default>

Christopher Ferris wrote:
> I don't disagree. However, the pre/post condition semantics need to
> (somehow) be expressed. REST itself doesn't address this. 

Two responses:

1. The pre and post conditions were what 
we did in UN/CEFACT. 
I think Paul is saying you might not need them.
That is, if you need a particular resource to which
to post a subordinate, if the resource doesn't exist,
you can't do it. (e.g. the precondition, that the
resource exist, is implicit.)
The postcondition, that the resource now does exist,
is also implicit.
(But I shouldn't speak for Paul too much...)

2. What I am saying (which maybe slightly different
from Paul's message) is that we got this REST
architecture already, so let's see how far we can
push it.  REST may not express everything, but
what can I express with REST and maybe a few
extensions after I've pushed it as far as it can go?

< Where would we find the declarative pre/post
> conditions expressed not only for a resource, 
> but for a class of resources? 
> for classes of related resources?

UN/CEFACT is coming up with a starter library.
To be published in the fall.  Including an RDF
representation.  *Not* REST.  But could be
RESTified pretty easily, I think.

> What this ends up looking like is a distributed 
> Makefile and how many people (especially
> business types!) can read, understand and internalize 
> a Makefile? In my expefrience, very few.

Actually, what it looks like is a UML model 
and an RDF representation, which is just 
as bad.

I think it is possible to derive a much simpler
business-language representation, and I am
personally committed to doing so, but will
let the dust settle before I get serious about it.

> Personally, I like declarative languages, I think it is a 
> superior approach.
> But, most people have a *really* hard time with them. 
> XSLT is a good example.
> Most people I know throw their hands up in despair 
> when faced with having to write, or worse debug, an 
> XSLT stylesheet:)

I'm going with patterns and templates.
We'll see how far I get.

-Bob Haugen
Received on Friday, 9 August 2002 15:34:38 GMT

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