Eric Norum wrote:
I agree with Michael that turning seq from a DFA into an arbitrary
procedural language interpreter is not a good thing.
On Apr 6, 2006, at 1:09 PM, Laznovsky, Michael wrote:
Hi- while this might be fairly easy to do given the way seq does its
internal bookkeeping, seems to me it would muck up the relatively clean
DFA state-machine model we have now. I've handled cases like you
describe
(e.g. an "ABORT" button that allows interrupting a long series of
states)
by adding extra intermediate states, as in:
state A
{
entry {
flag = OK;
}
when (<event>) {
if (trouble) flag = BUBU;
} state A_check
}
state A_check
{
when (flag == BUBU) { /* uh oh! */
} state A_abort
when () {
} state B /* next state */
}
The "out-of-order" transitions I mentioned referred to a future
debugging
environment, where it might be useful to interactively force a
transition
to an arbitrary state.
Looks like I could use some instruction on the value and use
of a DFA. All my SNL programs look like this:
state monitor {
when (A && B && C && D && E) {
...
} state action1
when (A && B && C && D && !E) {
...
} state action2
}
Ok, I'm exaggerating, but only a little. Nevertheless, it's true
that MOST of the things I need to to in EPICS that can't easily be
done in a database end up looking like the above. Maybe someone
knowledgeable could give a short course in how things really should
be done in SNL.
--
Tim Mooney ([email protected]) (630)252-5417
Beamline Controls & Data Acquisition Group
Advanced Photon Source, Argonne National Lab.
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- RE: snc/seq enhancements ... local-variable access Laznovsky, Michael
- Re: snc/seq enhancements ... local-variable access Eric Norum
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