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RE: grammars for pre-defined events like help, cancel, exit?

From: Scott McGlashan <scott.mcglashan@pipebeach.com>
Date: Tue, 23 Jul 2002 12:25:48 +0200
Message-ID: <2764A29BE430E64A92EB56561587D2E7107E4F@se01ms02.i.pipebeach.com>
To: "Lutz Birkhahn" <lbirkhahn@adomo.com>, <www-voice@w3.org>


thanks for your comments. 

These 'universal' grammars were defined in voiceXML 1.0. In VoiceXML
2.0, while we recognized that they may be useful, especially for novice
developers, we also recognized that they would rarely be used in
production grade applications. Hence, we introduce a property called
'universals' in 6.3.4 (see below). By default, no universal command
grammars are defined but the application developer can write their own
using <link>s which throw the appropriate events. This gives the
developer full control over the universal grammars activated in an
application and avoids, as you point out, conflicts between platform
grammars and developer grammars. However, if the developer wishes to use
the platform's grammars, then they can do so by changing the universals
property to, for example, 'all'. The language of the grammars are
determined by the xml:lang feature (see 3.1.1).

universal property:

Production-grade applications often need to define their own universal
command grammars, e.g., to increase application portability or to
provide a distinctive interface.   They specify new universal command
grammars with <link> elements.  They turn off the default grammars with
this property. Default catch handlers are not affected by this property.

The value "none" is the default, and means that all platform default
universal command grammars are disabled. The value "all" turns them all
on. Individual grammars are enabled by listing their names separated by
spaces. For instance "cancel exit help" is equivalent to "all".

Let me know if you need further information.

[leader, W3C VoiceXML 2.0 Dialog team] 

-----Original Message-----
From: Lutz Birkhahn [mailto:lbirkhahn@adomo.com]
Sent: Thursday, July 18, 2002 04:41
To: www-voice@w3.org
Subject: grammars for pre-defined events like help, cancel, exit?

I couldn't find any definition in the VoiceXML working drafts (20020424)
who is supposed to define the grammars for the pre-defined events such
"help", "cancel" or "exit".

Section 5.2.6 specifies "help" as a "pre-defined event", which should be
thrown when "the user has asked for help". But it is not defined how the
user can ask for help.

In section 3.1.4, "Activation of Grammars", it says:

   When the interpreter waits for input as a result of visiting a field,
   the following grammars are active:
   - [...]
   - grammars defined by platform default event handlers, such as help,
     exit and cancel.

Does this mean, the implementor of a VoiceXML platform has to define a
default grammar (probably in a <link> element inside <vxml>?) with some
"reasonable" contents? In what language?

IMHO the VoiceXML standard should either define a default grammar to be
for <help>, <cancel>, and <exit>, or it should explicitly state that
events have to be implemented by the user (VXML author). If every
implementor is forced to define his own grammars for these events,
are for sure (is "goodbye" handled by the VXML page or does it trigger
exit event being thrown?).

Hoping for some clarification or comments,


[it seems this mail didn't get through the first time. If you received
double, sorry]

Lutz Birkhahn                                       System Software
Adomo Inc. --  10001 N. De Anza Boulevard Suite 220  --  Cupertino, CA
Received on Tuesday, 23 July 2002 06:18:31 UTC

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