- From: Bijan Parsia <bparsia@isr.umd.edu>
- Date: Fri, 19 Sep 2003 21:55:44 -0400
- To: Drew McDermott <drew.mcdermott@yale.edu>
- Cc: www-ws@w3.org
On Friday, September 19, 2003, at 04:59 PM, Drew McDermott wrote: > [me] >> Suppose C sends a message to P two or more times, at least on >> some runs, e.g.: >> >> C = (seq (P) (if Q then ... else (P))) >> >> I've suppressed the actual dataflow, but assume that C is sending data >> to P and getting some back. With respect to a run of C in which Q is >> false after C interacts with (P), let P1 be that first interaction, >> and P2 be the second. > > [Bijan Parsia] > Fine. > >> What exactly are P1 and P2? > > Don't know, and don't care. > > *Someone* has to decide somewhere, sometime. Oh, I see. That's fine :) I even agree. > Judging from this and other things you've said, I'm guessing you're > adopting the Anthropomorphic Stance. Can I guess that you've conceded victory to me? :) > That is, you're visualizing P as > an entity that exists, minds its own business, lives and lets live, Uh. Well, introspection reports no such thing. But ok. > and occasionally gets messages that it feels compelled to respond to. This latter bit sounds more close to my understanding. > Fine. We can have *all* processes be like that if you want. Well, uh, is this my choice? This is pretty much what a SOAP/WSDL web service *is*, or is trending toward, AFAICT. > But P may be getting messages from many different agents > simultaneously. Yes. > It must keep track somehow of which messages are > starting a new conversation and which are following up an old one. Yep. > I > take it that the Anthropomorphic Stance holds that it's the _content > of each message_ that determines which conversation it's a part of. Well, I don't know. Are the headers part of the content? If I set up a session, is that part of it? But sure, why not? > The parts of a message that determine such things might be called > "correlation tokens." (Maybe that's exactly what they're called; I > know the word "correlation" is used in a way relevant to my > puzzlement.) Ok. > So my followup question is: Where in DAML-S (if anywhere) do we > specify the correlation tokens in messages? We totally punt on that. I regard this as a problem. In the stabs I've made at distributing control structure, I've run into this issue. I suspect it happens even if you retain the "single controlling interpreter with rpc calls", except I think that either the rpc calls are in fact stateless, or coordination is left to other mechanisms. Cheers, Bijan Parsia.
Received on Friday, 19 September 2003 21:55:30 UTC