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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: References on encoding (Hierarchical) State Machines / Automata
 in Ada?
Date: Wed, 13 Feb 2013 18:05:57 +0000
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Date: 2013-02-13T18:05:57+00:00
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david.mentre@gmail.com writes:

> Hello,
>
> Would somebody have references on the encoding of State Machines or
> Hierarchical State Machines in Ada?
>
> [...] The application domain is safety critical systems with real time
> constraints (timers).

There was a paper at an Ada UK conference a while back - the idea was
machine verification of hand-coded state charts; turned out that the
implementers didn't understand the state machines the way the designers
had intended, and they got them wrong anyway.

So I'd be reluctant to see hierarchical state machines used in
safety-related software; the simpler the better.

On the other hand, if you don't allow HSMs you will have separate
cooperating state machines; also tricky to reason about.