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Re: Controlling relevance in XForms 1.0 without changing context node and without using @context

From: Adrian Baker <adrian@fastmail.net>
Date: Mon, 09 Oct 2006 10:55:17 +1300
Message-ID: <452973C5.3080802@fastmail.net>
To: Mark Birbeck <www-forms-request@frink.w3.org>
CC: WWW-FORMS@W3.ORG

Hi Mark,

I guess I took Leigh's '/your/condition/here' path as just a placeholder 
for any expression! So sure, that path would be fine. Just to be clear 
then, if I had:

    <xf:group ref=".[invoice/currency='euro']">...</xf:group>

Then this would be an example of a dynamic dependency, correct?

Regarding your second point: now that I re-read the spec I see this. 
Perhaps 7.5.1 could be made clearer, because it gave me the impression 
that dynamic dependencies were 'unacceptable' in *all* binding 
expressions. In particular, this sentence seems quite general:

    "Not every possible XPath expression is acceptable as a binding 
expression."

Perhaps 'binding expression' could be qualified with 'model binding 
expression'. Or, since 7.5.2 already states this, perhaps this can be 
removed altogether.

A related question: here (7.5.1) the spec states that not every possible 
XPath is acceptable (ie not paths which create dynamic dependencies), 
whereas just below (7.5.2) it states that dynamic dependencies will 
require manual rebuilding - which implies that they *are* acceptable.

Which is it - are they prohibited? Or permitted, as long as the form 
author is aware they may have to manually trigger a rebuild? In which 
case the statement that 'not every XPath expression is acceptable' seems 
inconsistent.

Adrian

Mark Birbeck wrote:
> Hi Adrian,
>
> It's not a dynamic dependency, since for any given snapshot of the
> instance data, the result of this expression won't change until nodes
> are added or deleted, and then there will be a rebuild.
>
> Having said that, in this example it doesn't matter, since XForms
> allows dynamic dependencies in UI expressions. A recalculation of the
> nodes referenced is performed in the refresh phase, and then a
> 'rewiring' takes place automatically between the model and the UI.
>
> Regards,
>
> Mark
>
> On 06/10/06, Adrian Baker <adrian@fastmail.net> wrote:
>   
>>  Isn't this a case of
>> http://www.w3.org/TR/xforms/slice7.html#expr-dynamic-dependency
>> ?
>>
>>  Leigh Klotz wrote:
>>  <xf:group ref=".[/your/condition/here]">...</xf:group>
>>
>>
>>
>>     
>
>
>   
Received on Sunday, 8 October 2006 21:55:32 GMT

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