Re: SDL-News: sub-state machine and persistent state

Subject: Re: SDL-News: sub-state machine and persistent state
From: Eckhardt Holz (
Date: Thu Feb 13 2003 - 09:55:41 GMT

Become an SDL Forum Society member <>
The originator of this message is responsible for its content.
-----From Eckhardt Holz <> to sdlnews -----


with most recent version of SDL (SDL-2000) sub-states are available in
SDL. The concept is called composite states, similar to UML you can
decompose a state into a sub-state machine a shallow and a deep history
mechanism as well as multiple entry and exit points are available too.
You may also decompose a state into multiple semi-concurrent state
machines (alternating execution of transitions).
However, I am not sure, whether any of the SDL tools (e.g. SDT/TAU,
Cinderella, etc) does already implement these new concepts.
For more information on SDL-2000 see my webpages with a tutorial:

Eckhardt Holz

Scott Shen wrote:
> Hi:
> Does anyone know how to model sub-state machine in SDL? Is it correct to
> say that we can define sub-state machines in procedures but whenever the
> procedure is called the sub-state always starts from "start"?
> Now I want to have multiple sub-state machines (each is run in a
> procedure) running concurrently inside a process, therefore every time
> the process leaves and returns to a procedure the revisited procedure
> should remember what was its last sub-state and resume from the same
> sub-state. Is there any way allow me to do something like that in SDL?
> Or, is there a better (the right way) approach?
> Thanks,
> Scott Shen
> Sr. Software Architect
> Holley Communications Canada Inc.
> Tel: 604.233.3804, Fax: 604.231.8745
> ##300-13775 Commerce Parkway
> Richmond, BC V6V 2V4
> Canada

Dr. Eckhardt Holz
Institut für Informatik            Rudower Chaussee 25
Humboldt-Universität zu Berlin        D 12489 Berlin
Tel.: +49-30-20933116            Germany
Fax.: +49-30-20933112  

--End text from Eckhardt Holz <> to sdlnews --- For extra SDL Forum Society benefits join at <>

This archive was generated by hypermail 2a23 : Thu May 09 2013 - 16:05:49 GMT