Re: A state-machine language in XML

Stephane Bortzmeyer <bortzmeyer@nic.fr> Fri, 16 March 2007 20:47 UTC

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Date: Fri, 16 Mar 2007 21:45:31 +0100
From: Stephane Bortzmeyer <bortzmeyer@nic.fr>
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Subject: Re: A state-machine language in XML
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On Thu, Feb 22, 2007 at 03:52:13PM +0100,
 Stephane Bortzmeyer <bortzmeyer@nic.fr> wrote 
 a message of 19 lines which said:

> For those who would prefer a XML syntax:
> 
> http://www.w3.org/TR/2007/WD-scxml-20070221/

After reading it, I can summary:

The language is more powerful than Cosmogol. It includes things like
guards (conditions for the firing of the a transition, something which
is missing from Cosmogol, partly because it requires a language to
express boolean expressions; State Chart XML uses JavaScript).

Its syntax is obviously very different :-) And it uses the word
"target" instead of "next" for the state after the transition.

It has substates (using XML natural taste for recursivity), something
which could be useful in Cosmogol (X509, for instance, is described by
embedded state machines).

It has rich control abilities, again using JavaScript expressions.

The example http://www.cosmogol.fr/examples.html#door would look like:

<state id="Open">
  <transition event="Close it" target="Closed"/>
  <transition event="Blow it out" target="Gone"/>
</state>

<state id="Closed">
  <transition event="Open it" target="Open"/>
  <transition event="Blow it out" target="Gone"/>
</state>

<state id="Gone"/>

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