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SCXML: Conflict definition

From: Serge Voloshenyuk <serge_voloshenyuk@yahoo.com>
Date: Tue, 20 Mar 2007 14:44:45 -0700 (PDT)
Message-ID: <20070320214446.13176.qmail@web34303.mail.mud.yahoo.com>
To: www-voice@w3.org
>Two transitions conflict if the sets of states that they exit have a non-null intersection.

What about next sample:

<?xml version="1.0"?>
<scxml xmlns="http://www.w3.org/2005/07/scxml"  version="1.0"
       initialstate="prl">

    <parallel id="prl">
       <state id="p1">
          <initial>
              <transition target="p1_1"/>
          </initial>
          <state id="p1_1">
              <transition event="prl.done"  target="end1"/>
          </state>
       </state>
       <state id="p2">
          <initial>
            <transition target="p2_1"/>
          </initial>
          <state id="p2_1">
              <transition event="prl.done"   target="end2"/>
          </state>
       </state>
    </parallel>
    <state id="end1"/>
    <state id="end2"/>
</scxml>

It's conflict because destination states on event "prl.done" don't satisfy Harel's definition of compound <state> as OR-subset.

My opinion it was bad idea to introduce  algorithms for SCXML interpretation. This document will be read not only by implementors.
It's very difficult to understand this specification by potential users. 

There is simple Harel's semantics for compound states as generalization of OR/AND subset of leaf states for flat FSM.
Working of SCXML interpreter can be explained in this terms. 


 
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Received on Tuesday, 20 March 2007 21:44:51 GMT

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