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RE: Matching a choice grammar

From: Rajesh N <rajeshn@huawei.com>
Date: Wed, 22 Apr 2009 09:52:05 +0530
To: 'Pavel Cenek' <cenek@optimsys.cz>
Cc: www-voice@w3.org, ranjit@huawei.com
Message-id: <000101c9c301$e51bd580$2001120a@china.huawei.com>
Hi Pavel,

 

Thanks a lot for your inputs.

 

The doubt is whether a <grammar> element, which is a child of a <choice> of
a <menu>, should be considered as a menu grammar or as choice's local
grammar.

 

If it is to be considered as a menu grammar, then the scope=document applies
to it, and the behavior should be as you have clarified (like the way
Optimtalk works).

 

However, if it is not to be considered as a menu grammar, and just be
treated as <choice>'s local grammar, then the behavior should be as per the 

"else if ( the utterance matched a grammar belonging to a <choice> )"
branch of Appendix C.
 
It would be great if some more voices are heard on this issue.
 
Thanks
Rajesh

  

 

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From: Pavel Cenek [mailto:cenek@optimsys.cz] 
Sent: Tuesday, April 21, 2009 3:42 PM
To: Rajesh N
Cc: www-voice@w3.org; ranjit@hauwei.com
Subject: Re: Matching a choice grammar

 

Hi Rajesh and Puneet,

Let me comment on your question.

I believe that after providing the 5567 input in the second scenario, FIA
should jump to the menu, consequently 
the formVar in the form's scope will be inaccessible and error.semantic will
be thrown. This seems to me to be the logical behavior and this is how our
VoiceXML platform OptimTalk behaves.

Also, when you look into the VoiceXML 2.0 conformance test suite, the
assertion no 1085 states:
If a document scope menu grammar is matched while processing another 
form and the matched <choice> element's event or eventexpr is thrown
and the event handler does not transition to a new form, the FIA
resumes in the <menu> after clearing the menu's anonymous form
item variable.
This suggests that the interpreter must have tranistioned to the menu before
processing the event.

I find the cited formulation in Appendix C misleading. However, I am not
sure about the motivation for the 

else if ( the utterance matched a grammar belonging to a <choice> )

branch. For this particular use case it seems that simply removing it would
solve the problem. However, there is probably a good reason for having it
there. Anyway, it seems to me that a fix will be necessary here.

Regards,

   Pavel




-- 
      Pavel Cenek, CEO
      OptimSys, s.r.o.
      cenek@optimsys.cz
      Tel: +420 541 143 065
      Fax: +420 541 143 066
      http://www.optimsys.cz


Rajesh N wrote: 

Hi,

 

The following VXML script and couple of execution logs attached supplements
Puneet's earlier query.

Kindly go through the same and provide your suggestions.

 

VoiceXML script:

 

<?xml version="1.0" ?>

<vxml xmlns= <http://www.w3.org/2001/vxml> "http://www.w3.org/2001/vxml"
version="2.0">

 

 <property name="inputmodes" value="dtmf voice" />

 

  <catch event="error.semantic">

    <log> In error.semantic event handler </log>

    <exit/>

  </catch>

 

  <catch>

    <log> In generic event handler, event caught is <value expr="_event"/>
</log>

    <log> In generic event handler, variable formVar is  <value
expr="formVar"/> </log>

    <exit/>

  </catch>

 

  <menu dtmf="true" scope="document">

    <prompt> Welcome to menu </prompt>

    <choice event="myEvent1">

       first  

       <grammar src="builtin:dtmf/digits?length=4" />

    </choice>

    <choice dtmf="0" next="#form2" />

    <choice event="myEvent2" />

  </menu>

 

  <form id="form2">

    <var name="formVar" expr="100" />     

 

    <field name="field2" modal="false">

      <grammar version="1.0" root="digit" type="application/srgs+xml"
mode="dtmf">

        <rule scope="public" id="digit">

          <one-of>

            <item>666</item>

            <item>777</item>

          </one-of>

        </rule>

      </grammar>

      <prompt> second </prompt>

      <filled>

        <log> In filled of field2 </log>

      </filled>

    </field>

 

  </form>

</vxml>

 

Execution scenario1: During input collection of field2, provide input
matching menu level grammar.

 

Prompt: Welcome to menu

Input: 0 (matches choice no:2 ) - leads to form2

Prompt: second

Input: 1 (matches choice no:3) - FIA jumps to menu and throws myEvent2

<log>: In generic event handler, event caught is myEvent2

...Accessing formVar is menu scope leads to error.semantic

<log>: In error.semantic event handler

End of application

 

Execution scenario2: During input collection of field2, provide input
matching <grammar> which is a child of <choice>

 

Prompt: Welcome to menu

Input: 0 (matches choice no:2 ) - leads to form2

Prompt: second

Input: 5567 (matches digits?length=4 <grammar> child of choice no:1) - FIA
does not jump to menu. Throws myEvent1 in form scope

<log>: In generic event handler, event caught is myEvent1

<log>: In generic event handler, variable formVar is 100                //No
error.semantic here as formVar is accessible

End of application  

 

 

Is the behavior observed in execution scenario2 correct? Is it correct for
the interpreter to not jump to menu though the grammar which matched is a
child grammar of <choice>?

 

Thanks

Rajesh

 

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From: www-voice-request@w3.org [mailto:www-voice-request@w3.org] On Behalf
Of Puneet Sharma
Sent: Thursday, April 02, 2009 5:10 PM
To: www-voice@w3.org
Cc: ranjit@hauwei.com
Subject: Matching a choice grammar

 

Hi,

 

  I feel there is an ambiguity in behavior of <choice> element.

 

  Consider case, where while recognition in a <form> , <menu
scope="document">'s  choice is matched. Then, I feel there is an ambiguity
about scope of current execution of <choice> element. Specification does not
clarify either it should be <menu> or <form>. 

 

 

Please refer below section of Vxml 2.0  : 

http://www.w3.org/TR/voicexml20/#dmlAFIA

 

           Appendix C - Form Interpretation Algorithm

    //
    // Process Phase: process the resulting utterance or event.
    //
 
    Assign the utterance and other information about the last
    recognition to application.lastresult$.
            // Must have an utterance
 
    if ( the utterance matched a grammar belonging to a <link> )
      If the link specifies an "next" or "expr" attribute,
      transition to that location.  Else if the link specifies an
      "event" or "eventexpr" attribute, generate that event.
 
    else if ( the utterance matched a grammar belonging to a <choice> )
      If the choice specifies an "next" or "expr" attribute,
      transition to that location.  Else if the choice specifies
      an "event" or "eventexpr" attribute, generate that event.
 
    else if ( the utterance matched a grammar from outside the current
              <form> or <menu> )
    {
      Transition to that <form> or <menu>, carrying the utterance
      to the new FIA.
    }

 

        From this I understand that, if <choice> is matched from outside of
<menu> then execute <choice> without any transition to that <menu>, so it is
not clear that in which scope  event thrown by such <choice> element should
be handled.

          If it is <menu> then above specified algorithm does not allow that
because that grammar is from <choice>, and if it is <form>  then <form> will
be executing <filled> from some other scope which is not right to do.

 

    Please also clarify below points also considering above scenarios:

   Specification:  A menu can be viewed as a form containing a single field
whose grammar and whose <filled> action are constructed from the <choice>
elements. 

 

        This statement says that, <choice> is treated as <menu>/<form> level
grammar and  but <menu> can  specify scope attribute  which means <choice>
can be matched at global scope.   

 

Regards

Puneet 

 

 

 
Received on Wednesday, 22 April 2009 04:24:41 GMT

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