Re: Objects, processes, and encapsulation

[Twan Basten <tbasten@xxxxxxxxxxxxxx>]

p0072370 wrote:

> >ianeast wrote:
> >> Think we need to understand what '+' and '-' mean with regard to
> >> processes, before we can truly do justice to process inheritance.
> >An interesting problem. I don't pretend to have the final answer but
> >I've put some thoughts into a paper:
> >
> >T. Basten and W.M.P. van der Aalst. Inheritance of Behavior. Journal of Logic
> >and Algebraic Programming, 47(2):47-145, March/April 2001.
> >
> >It is available at my homepage: http://www.ics.ele.tue.nl/~tbasten/
> Thanks Twan. 84 pages, wow! Will take up an evening or two.
> Will get back to you.

If you skip the proofs it's not too bad :-). Go straight to the examples in either
process algebra (ACP) or Petri nets, whichever you like most.

> Notice in the abstract you refer to expressing inheritance in terms of
> blocking and hiding method calls. I suppose what I had in mind was
> whether there might be some basis in certain CSP operators.

The basic idea is that one process extends another process if you can't
distinguish the two processes after blocking and/or hiding the new methods (or
should I say actions in this community :-) added to the extended process.

Hiding/blocking methods is a means to motivate and define a notion of behavioral
inheritance.
In the end, it boils down to adding parallel, alternative, iterative or sequential
behavior under certain restrictions that guarantee that the old behavior is
preserved. Each of these extensions corresponds to nice operators ...

I would definitely be interested if someone is willing to translate the ideas to
CSP ...

Twan