VoiceXML 2.1 Development Guide

<initial> element

The initial element is used in mixed-initiative dialogs, (where the caller’s first utterances dictate application flow), allowing the caller to fill in form-wide information, (thus allowing the user to skip over the field prompts), with but one utterance. Usually, the first prompt in a mixed initiative dialog will query the caller for all information, and then only execute the fields when it determines that all field variables have not been filled. The initial element does not contain any grammars or filled events of its own; rather, it relies on the grammars and filled elements of each individual field.

usage

attributes

cond	Data Type: CDATA	Default: Optional (true)
	The cond attribute specifies a Boolean expression, which must equate to ‘true’ in order for the content to be visited and executed. (Additionally, the expr attribute must also be set to ‘undefined’, see below).
expr	Data Type: CDATA	Default: Optional
	The expr attribute specifies the initial value of the element; if this value is ‘undefined’, (default), then the element will be visited by the FIA and executed. If this attribute has a value other than ‘undefined’, then the element will not be visited until explicitly set to 'undefined', by use of the clear element.
name	Data Type: NMTOKEN	Default: Optional
	The name attribute specifies the name of the ECMAScript form item variable. Each name assigned to an Initial element must be unique, else a fatal error.badfetch will be thrown.

shadow variables

none

parents

<form>

children

code samples

<Initial cond-expr> sample

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

<vxml version = "2.1" xmlns="http://www.w3.org/2001/06/vxml">

<meta name="copyright" content="2012 voxeo corporation"/>
<meta name="maintainer" content="YOUR_EMAIL@HERE.COM"/>

<form id="F1">

<grammar xml:lang="en-us" root="TOPLEVEL">
<rule id = "TOPLEVEL">
<item> dummy </item>
</rule>
</grammar>

<initial name="Initial_1" expr="'SomeValue'" cond="false">
<prompt>
this Initial form item will be skipped, as the expression
is not equal to undefined and the condition is set to false.
</prompt>
</initial>

<block>
<goto next="#F2"/>
</block>
</form>

<form id="F2">
<grammar xml:lang="en-us" root = "myrule" mode="dtmf">
<rule id = "myrule" scope = "public">
<item> 1 <tag> out.F_1 = "1" </tag></item>
</rule>
</grammar>

<initial name="Initial_2" cond="true" expr="">
<prompt>
this inital form item will get executed, as the expression
is set to undefined and the condition is set to true pressing
DTMF 1 will execute the enclosed field.
</prompt>

<nomatch count="1">
<prompt>
Okay, I'll ask you for information one piece at a time.
</prompt>
<assign name="Initial_2" expr="true"/>
<reprompt/>
</nomatch>

<noinput>
<prompt>
Okay, the quiet type, eh?
I'll ask you for information one piece at a time.
</prompt>
<assign name="Initial_2" expr="true"/>
<reprompt/>
</noinput>

</initial>

<field name="F_1">
<prompt> try pressing DTMF 1.</prompt>
</field>

<filled>
<prompt> congratulations, the initial test was successful.</prompt>
</filled>

</form>
</vxml>

additional links

W3C 2.0 Specification

ANNOTATIONS: EXISTING POSTS

mtatum111

9/24/2008 10:45 PM (EDT)

I have a question on the <initial> element.
In the spec it has the following

This element controls the initial interaction in a mixed initiative form. Its prompts should be written to encourage the user to say something matching a form level grammar. When at least one input item variable is filled as a result of recognition during an <initial> element, the form item variable of <initial> becomes true, thus removing it as an alternative for the FIA.

Does this mean that if something is spoken, then expr="true" which causes the FIA to skip the <initial> on the next pass through? I was a little confused by the statement

When at least one input item variable is filled as a result of recognition during an <initial> element, the form item variable of <initial> becomes true, thus removing it as an alternative for the FIA.

mtatum111

9/24/2008 10:47 PM (EDT)

Also, would expr="true" or "'true'" if a spoken entry was made?

voxeoJeffK

9/25/2008 12:32 AM (EDT)

Hi,

It's not the "expr" that is set to true when a form level grammar match is made, it's the "name", which is the element's variable. Consider:

<initial name="startHere">

When the grammar is matched, startHere is assigned the value "true", and the next cycle of the FIA will skip it because the FIA only visits <initial> when its variable is undefined. If your program logic requires an <initial> tag to be revisited all you need do is clear the variable:

<clear namelist="startHere"/>

And now that will be again selected by the FIA.

hope that helps,
Jeff K.

mtatum111

9/25/2008 5:18 PM (EDT)

One more question, as I read the spec, I have come across the following for <initial>

From spec:
Note: explicit assignment of values to input item variables does not affect the value of an <initial>'s form item variable.

Does this mean that if you have already set input item variables then the <initial> element will still be executed. It sound like this is what it is saying.

For instance if we have the following where I have the field input of price set to 100, does this still mean that <initial> will be executed. I believe according to the spec it will.

<form id="main">
<var name="price" expr="100"/>
<initial>
<prompt>I will be collecting the price as well as the number
of items. You can say both now.
</prompt>
</initial>
<field name="price" type="currency" />
<prompt>What is the price</prompt>
</field>
<field name="quantity" type="number" />
<prompt>How many </prompt>
</field>

voxeoJeffK

9/26/2008 2:03 AM (EDT)

Hi,

Yes, you are correct. The <initial>'s form variable is distinct from other input variables. Whether or not the <initial> is visited is not determined by other input items.

Jeff K.