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Re: Sub-forms feature

From: Lars Windauer <lars.windauer@betterform.de>
Date: Wed, 21 Nov 2012 13:29:35 +0100
To: Nick Van den Bleeken <Nick.Van.den.Bleeken@inventivegroup.com>
CC: Erik Bruchez <erik@bruchez.org>, "<public-forms@w3.org>" <public-forms@w3.org>, "public-xformsusers@w3.org" <public-xformsusers@w3.org>
Message-ID: <CCD27F4D.14E43%lars.windauer@betterform.de>

Sorry if I might get a little bit sarcastic in this mail, I really do
appreciate a lot what you guys at the Forms WG are doing and I'm grateful
for it. But you are writing that your are "scared that everybody in the near
future wants nicely encapsulated sub-forms in XForms ..", sorry, this is
nothing to be scared of but the best thing that could happen!. Just imagine,
everyone want's XForms, people getting excited about XFormsŠ. haven't have
that for quite a while, what a big step forward.

And do we really have to support everything in first place, what's the
problem about having a very small loead-embed feature set (implementors
"must" support) at the beginning (no repeated subforms, no inclusion of
JavaScript / CSS) and other features declared as "should"Š. I think it would
not be the first time this happens.

My experience with load-embed is, that Joern and I tried to solve all
problems regarding load-embed at once and in theory. The result was that we
had to give up for the same reasons you mention here. But a week later we
focused on what we really do need in our projects and left the rest aside
and it worked out great. And as mentioned in my last mail, I have not
written a single XForms application in the last three years without using
load-embed. And the funny things, all these features we had in mind
load-embed should support as well, they were never needed until today, there
was always an elegant workaround. And by the way, utilizing load-embed in
various projects without changing the implementation over more than three
years makes it kind of future proof for me..

I can't say it often enough, for me it's not about if "load-embed" is in the
recommendation or not but about if I do think that XForms is the right
choice to build XML based enterprise(!) applications.

Kind regards


> I also definitely see the value of form embed, even more for custom components
> (in which you can define insertion points e.g.: for things like tab controls).
> But I do think that if we specify something in the spec, we need to have a
> clear interoperable answer to all the questions:
> €  styling 
> € the styling of the subform should not interfere the styling of the outer
> form?
> € maybe you want to be able to style the subform from the outer form?
> € event propagation
> € it is likely that if the events in the subform start from the root of the
> outer form, the outer form starts to behave unexpected
> € do we support sending events to arbitrary elements inside de sub-form?
> € can we send events from inside the sub-form to everywhere in the outer form?
> € how does embedding/referring host language depended resources (javascript,Š)
> behave? They probably should only effect the subform.
> € How to embed the same sub-form multiple times (inside and outside a repeat)
> I know that if you are the implementor of a solution of embedded forms you
> know the ins-and-outs of the feature and know how everything behaves, but if
> you're a plain XForms author the behaviour should also make sense and it
> should be future proof.
> I'm really scared that everybody in the near future wants nicely encapsulated
> sub-forms in XForms with an *easy* way to communicate from and to the subform
> (events, bindings, Š), the current proposal will prevent us from specifying
> something like this. One of the main reasons in my opinion, that we are
> currently hesitated to define a nicely encapsulated sub-form model, is that it
> is damn hard to implement in one of the main host-languages of XForms, but
> this is changing.
> Kind regards,
> Nick Van den Bleeken
> R&D Manager
> Phone: +32 3 425 41 02
> Office fax: +32 3 821 01 71
> nick.van.den.bleeken@inventivegroup.com
> www.inventivedesigners.com
> On 21 Nov 2012, at 11:43, Lars Windauer <lars.windauer@betterform.de> wrote:
>> Eric,
>> I see that there are still issues with load-embed. But there are issues
>> with other XForms techniques / controls as well and they are in the
>> recommendation (xf:range). I do think that most of the open questions
>> could be solved quickly. At betterFORM we have flags to control if CSS and
>> JS of the subforms should be included or not, the only real problem in my
>> point of view are ID clashes. Id clashes are a real (but more theoretical)
>> issue, but in practice I never had to deal with them at all. It is quite
>> easy for XForms authors to avoid them and there are far more complex
>> issues in XForms an author has to take care of writing XForms. In the end
>> it's the same like having duplicate ids in a single form, which is as
>> likely if you have to move all your (sub-)forms in a single big form.
>> I'm writing this because my daily work is to design and implement XForms
>> based enterprise applications (including forms validated by MBs of schema
>> data, XML instances with much more than 10.000 LoC..) and I don't see how
>> to do this without load-embed or at least some kind of analogue mechanism
>> to dynamically load forms into forms.
>> Personally I can live without having load-embed in the XForms
>> recommendation since it is already available as a betterFORM extension.
>> Like all our implementations do have custom extensions. But as said
>> before, I really do think that "load-embed" takes XForms a big step
>> forward regarding enterprise applications and that the XForms community
>> should focus much more on issues like this (e.q. model two model
>> communication, interoperability of XForms and XQuery and other enterprise
>> questions) since this is an area where XForms is the answer to
>> insufficient HTML(5) forms. If I remember correctly XForms is supposed to
>> be the successor of HTML forms, not it's straggler.
>> Cheers 
>> Lars
>> __
>> betterFORM; Lars Windauer
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>> On 21.11.12 07:05, "Erik Bruchez" <erik@bruchez.org> wrote:
>>> All,
>>> The XForms WG has an editorial meeting this week and we have been
>>> discussing the proposed XForms 2.0 sub-forms feature with
>>> `show="embed"`.
>>> There are issues with specifying this feature properly, as discussed
>>> in the past, in particular in this thread [1]. In short, sub-forms
>>> raise issues related to isolation, such as visibility of ids, event
>>> propagation, and applicability of CSS styles.
>>> One possibility would be to completely ignore these issues, and just
>>> specify plain inclusions (for which there are clearly valid use
>>> cases). However the working group thinks that this falls a bit short
>>> of a solid "sub-forms" feature.
>>> There is some pretty exciting work going in the HTML world with Web
>>> Components [2], and in particular the Shadow DOM. [3] These efforts
>>> are essentially a continuation of the ideas found in XBL (without the
>>> XML part) and aim at addressing the need for a component model. Taking
>>> care of isolation is a central part of this work.
>>> While we are not discussing the inclusion of a full component model
>>> with the sub-forms feature, trying to address any of the
>>> isolation-related issues of sub-forms would probably end up
>>> overlapping with the Web Components/Shadow DOM work, which we clearly
>>> don't want to do.
>>> So the working group's current proposal is that it is better to defer
>>> this feature to a further version of XForms. Then it could possibly
>>> leverage the Web Components/Shadow DOM efforts.
>>> Thoughts welcome.
>>> -Erik
>>> [1] 
>>> http://lists.w3.org/Archives/Public/public-xformsusers/2012Jun/0015.html
>>> [2] http://www.w3.org/TR/2012/WD-components-intro-20120522/
>>> [3] 
>>> http://dvcs.w3.org/hg/webcomponents/raw-file/tip/spec/shadow/index.html
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Received on Wednesday, 21 November 2012 12:30:13 UTC

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