W3C home > Mailing lists > Public > www-forms@w3.org > August 2006

Re: Switch case construct

From: Mark Seaborne <m_seaborne@mac.com>
Date: Fri, 18 Aug 2006 11:53:24 +0100
Message-Id: <E6CE1597-8835-43F4-8259-6BFED5FE16C8@mac.com>
To: www-forms <www-forms@w3.org>

But case doesn't take single node binding, and it isn't a form  
control.  The only benefit I can see that giving case single node  
binding, etc is that you can set the relevance of a case rather than  
the relevance of a trigger with a toggle action pointing at the case.  
Logically your form still consists of a set of cases with triggers  
used to toggle between them.

Is it definitely the case that the content of non-relevant groups  
have to be in memory? It might be worth asking for clarification on  
that from the working group.

John Boyer pointed out (http://lists.w3.org/Archives/Public/www-forms/ 
2006Aug/0059.html) that the working group has discussed this and come  
to a resolution about the implications of a case not being selected.  
Is this likely to satisfy your own requirement only to have to load  
into memory as much of the form as is in active cases (I know of at  
least 1 implementation that already does this)? If it does then I see  
no reason why you couldn't just use:

<xf:trigger ref="instance('dojo')/wf1">
	<xforms:action ev:event="DOMActivate">
		<xf:message level="modal">case 1 select event</xf:message>
		<xf:toggle case="Section-I"/>

	<xf:case id="Section-I">


with CSS to style your triggers as the trigger portion of tabs.

All the best


On 18 Aug 2006, at 10:43, Francisco Monteiro wrote:

> Mark,
> I am using  "conventional" model-based switching , if you look at  
> the xforms source you will see that the xf:case is used just as a  
> normal single node binding control.
> When I set about writing the XForms processor I looked at what was  
> available, looked at design patterns currently used by my clients  
> and BPEL/Workflow and then set about creating these composite  
> controls, nobody does creating of composite controls better then  
> Dojo and Yahoo!UI.
> The inner details of why I used tabswitch case is that for very  
> large forms we only need to parse what workflow the client wants,  
> with group I would have to parse the whole forms!
> Look at the XForms source and it answers many of your other questions.
> I have a "pattern" documentation and some clients use it for  
> Templating and writing special composite controls.
> Thanks
> Francisco
> From: www-forms-request@w3.org [mailto:www-forms-request@w3.org] On  
> Behalf Of Mark Seaborne
> Sent: 18 August 2006 10:14
> To: www-forms
> Subject: Re: Switch case construct
> Francisco,
> Surely the effect you achieve in your form, of using model based  
> relevance to determine which cases are potentially viewable by the  
> user, is already achievable using "conventional" model-based  
> switching? You could use group instead of switch/case, or, if you  
> were using switch/case as currently defined (rather than your own  
> tabswitch/case) you would just bind triggers styled to look like  
> tabs to you model. Either way the same effect is achieved.
> The thing that stands out about your tabswitch element is that it  
> manages case selection directly without the need for some other  
> mechanism, such as triggers. That is rather neat. So if switch was  
> to be changed to allow this kind of @appearance="tabbed" (for  
> example) then each case would automatically get its own trigger,  
> that would need to behave just like a normal trigger, I guess with  
> a default action of toggle to its parent case, triggered by  
> DOMActivate.
> I think that this might fall under the category of making common  
> design patterns easy for authors and could be considered by the WG.
> The simplest pattern achievable like this is to say all cases would  
> be relevant. If you wanted the mechanism to support relevance then  
> you would either need ref/bind on case.
> But then where would the auto-generated trigger get its label, etc  
> from?
> If you have to add to case single node binding, label, help, hint  
> and action it is arguable that you might as easily wrap them in a  
> trigger element as described above, which would give more  
> flexibility with styling, etc.
> So maybe switch/case is alright after all? I'm not sure.
> All the best
> Mark
> On 18 Aug 2006, at 08:22, Francisco Monteiro wrote:
>> My take on the whole switch-case construct is that it is too  
>> restrictive. The case element is a control so all rules about  
>> Xforms control should apply by this I mean enabled, disabled etc.  
>> When you are doing workflow and have tabbed switch, the case  
>> element is viewed as a "section" just as paper forms are written  
>> today.
>> I have a small example here which demonstrates what I am implying  
>> and it can be viewed here
>> http://showoff2.awardspace.biz/pack/pack/examples/tabswitch2.html
>> Most clients I have like it this way, they see up front what is  
>> enabled or disabled. Xforms must be viewed in terms of workflow,  
>> anything which helps users have a easy experience should be  
>> encouraged.
>> Regards
>> Francisco
Received on Friday, 18 August 2006 10:53:59 UTC

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