XML Multislot Grammars

In many IVR applications of moderate-to-difficult complexity, the developer needs the ability to populate multiple variable values from but a single utterance. For instance, one might want to present associated information from a captured utterance result to the caller without the caller actually querying the IVR system. A real-world example of how this would be useful might be:

Presenting relevant information when a match occurs for a name grammar: account details, phone number, or maybe even an address
Presenting make/model number for a match to a "part name" grammar
....or any number of things

As you can see, knowing how to author such a grammar is a very useful, if not required skill for grammar developers. One can do this by using a GSL-formatted grammar quite easily due to its exceptionally lightweight syntax, but the drawback of using GSL is that it is a vendor proprietary format, which will soon be deprecated entirely by all IVR providers. As such, developers who intend for their applications to have a lenghty life-cycle should consider authoring grammar content in the slightly-more-verbose, but W3C-compliant SRGS format, and use SISR-formatted interpretation returns.

Adding additional slots to a return when using SISR is actually quite easy: We simply create new variable-value assignments within the return tag using the below format:



 <item>

  utterance value

   <tag>

    out.slotname_1="interpretation value 1";

    out.slotname_2="interpretation value 2";

  </tag>

 </item>

We then access these slot values within the VoiceXML dialog by using the syntax that one would use for any slot-defined grammar:



 lastresult$.interpretation.[slotname]

To better illustrate these concepts, we present a fully fleshed out grammar, and dialog, both of which can be downloaded, tested and then edited to fit your own customized content:

XMLMultislotGrammar.xml



<?xml version= "1.0"?>

<grammar xmlns="http://www.w3.org/2001/06/grammar" xml:lang="en-US" root = "MCCARTHY">



  <rule id="MCCARTHY" scope="public">

    <one-of lang-list="en-US">



      <item>

       the orchard keeper

          <tag> out.title="The Orchard Keeper"; out.year="1965"; </tag>

      </item>



      <item>

        outer dark

          <tag> out.title="Outer Dark"; out.year="1968"; </tag>

      </item>



      <item>

       child of god

          <tag> out.title="Child of God"; out.year="1974"; </tag>

      </item>



      <item>

       suttree

          <tag> out.title="Suttree"; out.year="1979"; </tag>

      </item>



      <item>

        blood meridian

          <tag> out.title="Blood Meridian: Or the Evening Redness in the West"; out.year="1985"; </tag>

      </item>

      <item>

       all the pretty horses

          <tag> out.title="All the Pretty Horses"; out.year="1992"; </tag>

      </item>



      <item>

       the crossing

          <tag> out.title="The Crossing"; out.year="1994"; </tag>

      </item>



      <item>

       cities of the plain

          <tag> out.title="Cities of the Plain"; out.year="1998"; </tag>

      </item>



      <item>

       no country for old men

          <tag> out.title="No Country for Old Men"; out.year="2005"; </tag>

      </item>



      <item>

       the road

          <tag> out.title="The Road"; out.year="2006"; </tag>

      </item>



  </one-of>

    </rule>

</grammar>

Utterance	Slot= 'title'	Slot= 'year'
`blood meridian`	`out.title="Blood Meridian: Or the Evening Redness in the West";`	`out.year="1985";`

And what about the invoking VoiceXML code, you ask? Look no further:

SISR_Multislot.xml



<?xml version="1.0" encoding="UTF-8"?>

<vxml version = "2.1">



  <form id="MainForm">

    <field name="F_1">



    <grammar src="XMLMultiSlotGrammar.xml" type="application/grammar-xml"/>



    <prompt>

     What is your favorite novel by Cormac McCarthy?

    </prompt>



    <filled>

     <prompt>

      <value expr="lastresult$.interpretation.title"/>,

       is an exceptional piece of literature, and was well received by readers, critics,

       and Pee Wee Herman when it was originally released in

      <value expr="lastresult$.interpretation.year"/>.

     </prompt>



     <log expr="'*** INTERPRETATION RESULT = ' + lastresult$.interpretation.title"/>

     <log expr="'*** INTERPRETATION RESULT = ' + lastresult$.interpretation.year"/>

    </filled>



    </field>

  </form>



</vxml>

Download the Code!

Download the source code

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SRGS-SISR: Grammar Slots

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