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RE: ISSUE-827: bug in detecting final states [SCXML-LC-Comments]

From: Zhou, Guojun <guojun.zhou@intel.com>
Date: Tue, 29 Jan 2013 17:02:42 +0000
To: Voice Browser Working Group <w3c-voice-wg@w3.org>, "www-voice@w3.org" <www-voice@w3.org>
Message-ID: <22B15B6D6C7C0D449E8F870C48CA2B1048BA976A@ORSMSX107.amr.corp.intel.com>
Can someone help remove me from this list? I am no longer doing work in this area. Thanks very much in advance!

-----Original Message-----
From: Jim Barnett [mailto:Jim.Barnett@genesyslab.com] 
Sent: Tuesday, January 29, 2013 7:01 AM
To: Voice Browser Working Group; www-voice@w3.org
Subject: RE: ISSUE-827: bug in detecting final states [SCXML-LC-Comments]

Here's a further detail to consider:  a state machine may enter a <final> child of <scxml> on any transition, even if there are still events in the internal event queue.  In that case, should the state machine process those events, or should it stop immediately?  In some sense, this is a distinction without a difference, because if the state machine is in a <final> child of <scxml>, no transitions are available to take.  An external observer will never see a difference between an implementation that processes the remaining events, and one that doesn't.  But at the algorithm/code level, the difference is significant.

-----Original Message-----
From: Voice Browser Working Group Issue Tracker [mailto:sysbot+tracker@w3.org] 
Sent: Tuesday, January 29, 2013 9:11 AM
To: w3c-voice-wg@w3.org; www-voice@w3.org
Subject: ISSUE-827: bug in detecting final states [SCXML-LC-Comments]

ISSUE-827: bug in detecting final states [SCXML-LC-Comments]


Raised by: James Barnett
On product: SCXML-LC-Comments

>From Gavin Kistner:

Consider this test case:

    <scxml xmlns="http://www.w3.org/2005/07/scxml" version="1.0" name="HistoryTest">
      <state id="s" initial="s1">
        <state id="s1">
          <onentry><raise event="go"/></onentry>
          <transition event="go" target="pass"/>
        <final id="pass"/>

And this test runner:

    final2 = RXSCy.Machine(@data['final2']).start
    assert(final2.is_active?('pass'),"final2 should pass")
    refute(final2.running?,"final2 should not be running")

In my interpreter, the first assertion works, but the second fails. The state machine enters the 'pass' final state, but the `running` flag is never set to false.

Looking at the algorithm, I don't see where it this case is covered. There are only two spots where running is set to false. The first is when receiving an external cancel event during the mainEventLoop, and the other is at the end of enterStates:

    for s in configuration:
            if isFinalState(s) and isScxmlState(s.parent):
                running = false

1) Is my test case wrong? Should entering the 'pass' final above not kill the interpreter?
2) Or should the above pseudo-code be `if isInFinalState(s) and isScxmlState(s.parent)"`?

Received on Wednesday, 30 January 2013 10:51:30 UTC

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