Re: csp as database query language

["Gordon Hutchison" <gordon_hutchison@xxxxxxxxxx>]

Do you mean something analogous to the "ready set" for a process - i.e.
those events the process will
accept from it's environment being the result set of the query processed at
that point?

I was often warned that visibility of the offered events of a process
without them actually
occurring led to a break down of some of the useful mathematical properties
of composed CSP
processes. Can anyone (re)explain this to me....  :-)

I was interested in it in order to take specification processes that, for
example, had things like sets and
looking at how they might be implemented with real queues by composing the
unchanged process
offering any one of a number of events with another "event
scheduling/priority"  type process that had
some knowledge of the "order" that the events appeared in the ready set of
the other process and/or the
"importance" of hte other processes/events which could remain unchanged
from the spec version.

Gordon.




                                                                                                                                    
                      "Campbell, John"                                                                                              
                      <John.Campbell@siin        To:       <occam-com@xxxxxxxxx>                                                    
                      et.trw.com>                cc:                                                                                
                                                 Subject:  csp as database query language                                           
                      14/03/2003 17:52                                                                                              
                                                                                                                                    
                                                                                                                                    



Dear All

The mindset of most people using CSP (or manifestations
of it like OCCAM) is to write programs to *make* something
happen.  I've been thinking the last few days that there
might be a useful alternative interpretation.

It seems to me that you could write a CSP description of
a *hypothetical* process that might be at work in a large
data base.  You could do a probablistic analysis to see
how many matches you'd expect in a random system, and
test the csp with the real system to see actual matches.

Thoughts anyone?
-jc