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Re: exf:iterate ?

From: John Boyer <boyerj@ca.ibm.com>
Date: Sun, 20 May 2007 23:12:35 +0530
To: mark.birbeck@x-port.net
Cc: "Adrian Baker" <adrian@fastmail.net>, "David Landwehr" <david.landwehr@picoforms.com>, www-forms@w3.org, www-forms-request@w3.org
Message-ID: <OF2F0CC39F.52E8F576-ON652572E1.005F0070-652572E1.006147EC@ca.ibm.com>
We resolved [1] to remove 1.1 from 1.1, since @while can at least satisfy 
all iteration requirements (though sometimes iteration is more pithy).

I have added it to Future Features, including a description of some of the 
issues that spec ready text would have to handle.   The issues are around 
insertions, value changes and especially deletions that could change the 
nodeset over which the iteration is occurring.  Put another way, the issue 
is that someone needs to write the spec to say what the answers will be 
and then everyone else needs to actually agree.  For example, there are 
three opinions about what should happen if nodes are deleted from the 
action sequence (don't do that, the nodes disappear, the nodes still exist 
as orphans). 

In essence, the iteration attribute creates a situation that is found 
nowhere else in the entire action system.  For every other action, the 
attributes of the action are a "point solution" in that they apply only to 
what that action does at a particular moment in time.  The values of the 
attributes are not needed once the action completes.  This is even true of 
@while. 

Finally, it should also be noted that some of the main use cases for an 
iteration attribute have also since been addressed by modifications to 
insert and delete to allow them to operate over a whole nodeset, so the 
most prevalent use cases for adding the feature have been addressed 
without adding enough features to create the issues above.

[1] 
http://lists.w3.org/Archives/Member/w3c-forms/2005OctDec/att-0134/2005Oct20.html#resolution1
[2] 
http://www.w3.org/MarkUp/Forms/wiki/Create_a_construct_for_actions_that_iterates_over_a_nodeset

John M. Boyer, Ph.D.
STSM: Lotus Forms Architect and Researcher
Chair, W3C Forms Working Group
Workplace, Portal and Collaboration Software
IBM Victoria Software Lab
E-Mail: boyerj@ca.ibm.com 

Blog: http://www.ibm.com/developerworks/blogs/page/JohnBoyer





"Mark Birbeck" <mark.birbeck@x-port.net> 
Sent by: www-forms-request@w3.org
05/11/2007 10:39 PM
Please respond to
mark.birbeck@x-port.net


To
"David Landwehr" <david.landwehr@picoforms.com>
cc
"Adrian Baker" <adrian@fastmail.net>, www-forms@w3.org
Subject
Re: exf:iterate ?







I agree, David. We have implemented all of your attributes, including
@iterate. :)

On 11/05/07, David Landwehr <david.landwehr@picoforms.com> wrote:
>
> I could not agree more and I found it a little strange that the working
> group did not adopt all the attributes. As far as I recall there was no
> particular reason that @iterate was dropped other than that the iterator
> description did not specify what happens when a node which it is
> iterating was deleted (however this could happen it other circumstances
> as well).
>
> Best regards,
> David Landwehr
>
> Adrian Baker skrev:
> > I'm suprised that there's no equivalent of the @exf:iterate attribute
> > (http://www.exforms.org/conditionals.html#id4484032) in XForms 1.1, to
> > go with the @while attribute.
> >
> > You can achieve the same thing with @while, but it's very cumbersome
> > because the context node doesn't change, so you need to initialise a
> > separate counter & manually increment it.
> >
> > Adrian
>
>
>
>


-- 
  Mark Birbeck, formsPlayer

  mark.birbeck@x-port.net | +44 (0) 20 7689 9232
  http://www.formsPlayer.com | http://internet-apps.blogspot.com

  standards. innovation.
Received on Sunday, 20 May 2007 17:43:00 GMT

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