Re: xforms:item and xforms:itemset: label and value bound to non-existing nodes

Hi Allan and Eric,

When the label has an empty nodeset, the string result of that is empty 
string. 
Non-relevance also typically gets styled as non-visible, so in both of 
those cases the label of the item would not be seen.
Non-relevance could also be styled as disabled, but for a label to be 
disabled means that it is greyed out.

But we don't have anywhere in which the label being non-relevant or empty 
affects the control for which it is a label.

Non-relevance is applied based on a UI binding between the control and the 
model.  We have direct language in 
the spec that says if you have no UI binding, then relevance does not 
apply.  We also have special language that
says that the implicit group within each iteration of an unrolled repeat 
acts as if it has a UI binding with respect to 
inheriting model relevance.

We could *add* language that says that the relevance of each node of an 
itemset's nodeset is applied to the
generated item,  but that language doesn't exist now, and if it did, then 
we would have an inconsistency because
there is no way currently to put a UI binding on the explicitly declared 
items.

So, right now relevance does not get applied to items, regardless of how 
they are declared.

John M. Boyer, Ph.D.
Senior Product Architect/Research Scientist
Co-Chair, W3C XForms Working Group
Workplace, Portal and Collaboration Software
IBM Victoria Software Lab
E-Mail: boyerj@ca.ibm.com  http://www.ibm.com/software/

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





"Allan Beaufour" <beaufour@gmail.com> 
Sent by: www-forms-request@w3.org
04/19/2006 01:36 AM

To
"Erik Bruchez" <erik@bruchez.org>
cc
"Xforms W3C WG" <www-forms@w3.org>
Subject
Re: xforms:item and xforms:itemset: label and value bound to non-existing 
nodes







On 4/18/06, Erik Bruchez <erik@bruchez.org> wrote:
> I am not sure that the spec is very explicit on this matter. Consider:
>
> <xforms:item>
>    <xforms:label ref="some-label"/>
>    <xforms:value ref="some-value"/>
> </xforms:item>
>
> Now what if "some-label" doesn't point to a node? This is probably the
> same as, say, an xforms:input label not pointing to a node. Does this
> mean that the XForms engine handles:
>
> o The label as non-relevant?

Yes, it is a form control, so it should be non-relevant then.

> o The label as an empty string?

Hmm, it's not bound to anything at all, so "null" would be more correct I 
guess.

> o The whole item as not available for selection?

And here comes the tricky part :)

I would say that if a value is non-relevant, the item should not be
choosable in a select(1), no matter the state of the label. (I would
go for not displaying the item, but with a relevant label, you could
possibly show a non-selectable/greyed-out label).

A non-relevant label with a relevant value... I cannot see the use of
it, but the item should then have a blank label? I'm not sure about
this...

> Same question when "unrolling" the xforms:itemset. Say you have
> something like this:

I think whatever behaviour is defined for an item, also goes for the
"unrolled" items in an itemset.

--
... Allan