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Re: April CCXML: test case conflicts with ECMA rules

From: Chris Davis <davisc@iivip.com>
Date: Fri, 23 Apr 2010 09:15:45 -0500
Message-ID: <4BD1AB91.4020409@iivip.com>
To: www-voice@w3.org
CC: Petr Kuba <kuba@optimsys.cz>
Petr, thanks for the response.

I don't see how any CCXML implementation can be passing this test case. 
Is yours passing?

When you say:
"When this condition is being evaluated there is no "id" in current 
(Transition) scope because this variable will be declared couple of 
lines later in <var>."

that is incorrect. The  declaration of id will be made in the current 
scope(transition), regardless of where it sits visually in the 
transition. It doesn't get "declared later" - ECMA declares it inside 
the transition scope, which is visible when the ECMA first runs the 
transition.

If you comment out the var id declaration, then yes ECMA will see id 
from the parent scope. However - by declaring a var id in the new scope 
you are evaluating the local id value (undefined because the assignment 
has not taken place after the if) when ECMA runs inside the transition 
scope.

I've attached an html file with a short javascipt that demonstrates this 
misunderstanding of ECMA scopes.
Try it on Windows/Explorer, Linux/Mozilla etc, you will always get the 
output:

show ECMA function scope test
see? id is undefined...id=undefined

Here is the textual content of the attachment:
<html>
<body>
<pre>
<script type="text/javascript">
document.write("show ECMA function scope test\n");
var id=2;
function foo()
{
        if(id==2)
        {
                document.write("this won't run");
                var id = 3;
        }
        else
        {
                document.write("see? id is undefined...id="+id);
        }
}
foo();
</script>
</pre>
</body>
</html>

Regards,
Chris

Petr Kuba wrote:
> Hello Chris,
>
> I believe that the test case is correct. It tests the parent scope 
> chain delegation model as described in the CCXML specification but it 
> doesn't expect "if" to open a new scope.
>
> Let's see the statement you find offending:
>
> <if cond="id==session.id">
>
> When this condition is being evaluated there is no "id" in current 
> (Transition) scope because this variable will be declared couple of 
> lines later in <var>. Therefore searching continues in scopes CCXML, 
> Application and Session. The "id" variable is found in the Session 
> scope and therefore the condition is "true".
>
> You assume that the variable exists in the Transition scope and has 
> value 'undefined' but it is not correct. The variable doesn't exist at 
> the time when the condition above runs.
>
>
> Regards,
> Petr Kuba
>


-- 
Chris Davis
Interact Incorporated R&D
512-502-9969x117




Received on Friday, 23 April 2010 14:16:42 GMT

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