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Re: Choreography blogging

From: Kohei Honda <kohei@dcs.qmul.ac.uk>
Date: Tue, 21 Feb 2006 01:54:12 +0000
Message-ID: <43FA72C4.1090709@dcs.qmul.ac.uk>
To: 'WS-Choreography List' # <public-ws-chor@w3.org>
CC: Steve Ross-Talbot <steve@pi4tech.com>, Gary Brown <gary@pi4tech.com>, Nobuko Yoshida <yoshida@doc.ic.ac.uk>, Marco Carbone <carbonem@dcs.qmul.ac.uk>, Kohei Honda <kohei@dcs.qmul.ac.uk>

teve Ross-Talbot wrote:

 >
 > Check out:
 >
 > http://polarlake.typepad.com/warren/
 >
 >

Quite an interesting observation. Two points:

(1) Mr. Buckley's view focusses on a run-time view (run-time means
what happens in situ, in live) of CDL, and says fixing description is
useful for controlling the run-time. A charming understanding of
dynamism between description and what is realised.

(2) And this is far from being inconsistent with the use of static
abstraction such as types, logics and others:

--- First, it helps you to write down a reference description which
    you are sure means what you want.

--- Second, it enhances clarity of description itself, and gives
    us the idea what it is like (as dtd and schemas do).

--- Third, it can give useful info to a run-time: a monitor can
    rely on extra information for controlling interaction. A simple
    one: you should send two integers rather than one boolean.
    A more complex: You never give low quote to more than 10
    customers. Analogous to the use of run-time types in JVM.

Well I realise there are more.

--- Fourth, you can write a meta-specification. You start from a fixed
    choreo, which, depending on what is observed at run-time, can be
    updated and replaced at run-time. A new choreography can even be
    generated at run time. Perhaps like some modern dance performance?
    (Pina Bausch's)?  Or like writing scripts for the next scenes as a
    movie is being screened, as some directors seem to be doing?
    (close Mr. Buckley's feedback loop).

--- Fifth, your static abstraction is even more important when we
    allow such dynamic configuration. In fact it will be near
    impossible to control such evolvable behaviour without a basic notion
    of  typing. If a director can change dancing in situ, and if that 
director
    can go  completely mad (at run-time, say), how can you be sure
    everything works all right?

Surely there will be more, but let's finish here. As an academic note,
process algebras such as pi-calculus and CSP would offer a basic tool
for studying such complex run-time behaviour.

kohei
Received on Tuesday, 21 February 2006 01:53:53 UTC

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