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Re: Draft minutes for 2007-12-19

From: John Boyer <boyerj@ca.ibm.com>
Date: Wed, 19 Dec 2007 10:18:44 -0800
To: "Leigh L. Klotz, Jr." <Leigh.Klotz@Xerox.com>
Cc: public-forms@w3.org
Message-ID: <OF747B4DE1.5F92A124-ON882573B6.0062E5B0-882573B6.006496AB@ca.ibm.com>
Hi Leigh,

This is a great set of minutes.  Nice way to end out the year.

Right near the bottom, you have me saying this:
We can double check with Steven, but my prior experience is that we can 
produce other documents in addition to the requirements
but what I think I said was this:
We can double check with Steven, but my prior experience is that we can 
produce other documents in support of the charter requirements
Best regards,
John M. Boyer, Ph.D.
Senior Technical Staff Member
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
Blog RSS feed: 

"Leigh L. Klotz, Jr." <Leigh.Klotz@Xerox.com> 
Sent by: public-forms-request@w3.org
12/19/2007 09:22 AM


Draft minutes for 2007-12-19

Please respond with corrections.
Please start new threads for discussion.

W3C Forms teleconference December 19, 2007
* Present
Charlie Wiecha, IBM
Erik Bruchez, Orbeon
John Boyer, IBM (chair)
Leigh Klotz, Xerox (minutes)
Mark Birbeck, x-port.net
Nick van den Bleeken, Inventive Designers
Uli Lissť, Dreamlabs
Keith Wells, IBM
Blake Jones, DAISY/ViewPlus
Sebastian Schnitzenbaumer, Dreamlabs
* Agenda
Next Teleconference
Offlist ping about answer for charset and encoding (action MarkB on May 2)
Proposal to let XPath 2.0 be used with XForms 1.2 via a modularization 
IRC Minutes
Meeting Ends
* Next Teleconference
John Boyer: Our next telecon is January 9, 2008. It starts 15 minutes 
earlier and runs 15 minutes later in your time zone.
* Offlist ping about answer for charset and encoding (action MarkB on May 
Mark Birbeck: I'll try to get to this before we break for the year.
* Proposal for XForms 1.2 to allow custom function definitions
(and don't add functions like decimal-string() and sum-product()) 
John Boyer: Thanks to Erik, Uli, and Nick for holding the email 
discussion. Nick pointed out that we might need to define custom 
Erik Bruchez: Both XQuery and XSLT 2.0 support it; even custom functions 
in XSLT. The idea is that you use the constructs to define a function you 
can use any place you have XPath expressions (style sheet, model). We 
might be less tempted to add functions all over the place; you can achieve 
re-use by writing your own function. XSLT and XQuery are quite complete 
languages and XForms is not, so I'm not sure of the details. The simplest 
thing would be a way to assign a function as another XPath expression.
John Boyer: I like the extension idea. Or a way of wrapping XForms 
actions, and not have them mutate objects other than in the functions. 
Then you can use @if and @while.
Erik Bruchez: I think that would be good to be able to use actions. Not 
being able to re-use sequences of actions with parameters is a problem; 
you can re-use actions by dispatching to the model, but without parameters 
or return values. You have to use hack instances and it's awkward.
John Boyer: The xforms:function concept could easily use xforms:param or 
something els like XSLT templates. We'll get pushback if we don't make a 
limitation that the function can't have side effects. So we could limit it 
to the instance inside the function.
Erik Bruchez: In XPath you want them side-effect free as well. But imagine 
a function that returns void (empty sequence, empty nodeset) which does 
actions. If there were a way, it would cover some use cases, but I'm not 
sure how. But extension functions can have side effects. At the low level 
of the implementation, XPath allows side effects.
John Boyer: So there is a way to signify that there are side effects? That 
runs roughshod over our ability to track dependencies.
Erik Bruchez: I don't know if it's in the spec.
John Boyer: We got into trouble with Michael Kay over XPath before with 
the random and now functions. Modifying the instance is even more 
Erik Bruchez: With XQuery and XSLT 2.0 it's all XPath 2.0; Michael Kay 
says they don't really differentiate between XSLT 2.0 elements and XPath 
functions. ... and the value is an XPath expression. So you could get 
John Boyer: It reminds me that we need to tell the difference between side 
effects or not. That reminds of of Pascal procedures vs. functions. We 
could have functions being side-effect free and procedures a reusable set 
of actions, and get around the parameter problem. Anybody else have 
Leigh Klotz: I think we should focus on the interface and not the 
implementation and consider this part of the interface to XForms, and then 
towards being able to add libraries of custom libraries.
John Boyer: I think that is a separate feature; if you want to be able to 
write something that works everywhere, we have a way to do that.
Leigh Klotz: I think they're two separate problems and we should try to 
think of them separately and make sure it meets in the middle. There are 
three things: how and what we add (and we have identified two nascent 
points: XPath functions and actions), how they are specified (the 
inflection point) and then how to implement them, and on that last one, 
wholly self-contained implementations may be possible for many, but we 
should also allow native or external implementations (JavaScript or 
internal) which will encourage the development of function libraries as it 
has for XSLT.
John Boyer: Nick, anything to add.
Nick van: [irc] I'm agreeing with it
John Boyer: Should we do this for XForms 1.2?
Nick van: [irc] but what we do then with sumproduct?
Mark Birbeck: I'm agreeing too. The sooner we start addressing reusability 
the better.
John Boyer: It's not easing on-the-glass but it does ease authoring.
Nick van: It's my feeling too. If we don't add it in 1.2 then we still 
have the problem with sumproduct in 1.2. That's the main reason I proposed 
the ability to define functions.
John Boyer: It shoots the necessity of adding sumproduct, decimalstring, 
and others we haven't come across. It addresses reusability and Erik's way 
of having an easier way to invoke things.
Nick van: We can add a list of them in an appendix just like XSLT has.
John Boyer: Yes, as Leigh says, a native implementation can be faster and 
an implementation could decide to use it.
Leigh Klotz: I'm hearing namespaces there. It's just like in XSLT and 
John Boyer: I think we have a proposed resolution to work on this for 
XForms 1.2.
John Boyer: Proposed Resolution: Add to XForms 1.2 the capability to 
express function and procedure interfaces and implementations.
Leigh Klotz: Are actions and xpath the only two points we plug things in?
John Boyer: Those are the only two things with regard to side effects; 
either have them or they aren't.
Leigh Klotz: Are xpath expressions (model and ui) and actions the only two 
places? What about presentation controls as in XBL? Or are we far enough 
away from presentation by being abstract.
John Boyer: So the eventing paradigm might be one, the event handlers.
Leigh Klotz: That's events again. I just want to make sure there's enough 
Mark Birbeck: In XML Events 2 we added the ability to add have script 
inside action sequences. So, it means that the distinction among action, 
script, and function starts to blur. And secondly, I wonder if we can make 
use of it to allow calling an action from an XPath expression.
Leigh Klotz: There's also validation; Schematron plugs XPath into other 
Schema languages. We use XPath for that already, but can we plug in new 
functions there? Or how about serialization? I want to make sure that it's 
not just xf:action/* and */[@nodeset or @ref or @value] that we can use.
John Boyer: Can we get some wording?
Leigh Klotz: "Add to XForms 1.2 the capability to define interfaces to and 
implementations of extensions for both side-effect and side-effect-free 
operations, along with the specification of which points these extensions 
may be invoked, including but not limited to XPath expressions and 
John Boyer: Good. [irc] CharlieWiecha, John_Boyer, ebruchez, Nick, wellsk, 
Blake, markbirbeck, Schnitz.
John Boyer: So resolved.
Resolution 2007-12-19.1: Add to XForms 1.2 the capability to define 
interfaces to and implementations of extensions for both side-effect and 
side-effect-free operations, along with the specification of which points 
these extensions may be invoked, including but not limited to XPath 
expressions and actions.
John Boyer: Who wants to take the action item to pull together some 
spec-ready text?
Erik Bruchez: We should come up with a proposal for syntax first.
John Boyer: I agree. It'll take a couple of iterations. You could write 
sumproduct or decimal string as examples.
Erik Bruchez: I am not sure I can commit to write the whole thing but I 
can get the ball rolling for how to declare a procedure in the XForms 
Nick van: [irc] sounds perfect for me
John Boyer: Nick you want to do it?
Nick van: No, Erik will do.
Leigh Klotz: I will go look for more places to add it.
John Boyer: Sounds like two actions.
John Boyer: Erik, can you own this?
Action 2007-12-19.1: Erik Bruchez to send email to write up initial draft 
for extensions.
Action 2007-12-19.2: Erik Bruchez to produce spec-ready text for XForms 
1.2 extensions.
Action 2007-12-19.3: Leigh Klotz to investigate and report on possible 
uses for extension functions outside of xf:action/* and */[@nodeset or 
@ref or @value].
* Proposal to let XPath 2.0 be used with XForms 1.2 via a modularization 
Erik Bruchez: If we delay XPath 2.0 to XForms 2.0, then it may take years. 
If we add function libraries it may be less important. However, we still 
need it. In the XProc work we are doing with W3C, based on feedback from 
Michael Kay and others, we decided to allow either 1.0 or 2.0 and specify 
in the program whether the form author is requesting 1.0 or 2.0. There is 
decision logic in the spec that gives maximum flexibility to authors and 
implementors. I think we can do this before XForms 2.0. Also, if we have a 
big spec, then it will take a long time to get there. Our experience with 
XPath 2.0 shows you can integrate it in a light-weight way with most of 
the benefits. So I think it would be a good idea to try to specify XPath 
2.0 support in modular way on top of XForms 1.1 or 1.2.
Nick van: [irc] we maybe even want to allow different languages for the 
query (to specify node sets and refer nodes), constraint and calculation 
John Boyer: In the XML Signatures recommendation they had different 
algorithms at different requirement levels. For filtering, for example, 
there were "should" and "may" and "must". So we may want to talk about an 
optional XPath 2.0 binding.
Nick van: [irc] If we do add XPath 2.0 I would prefer we first try if we 
could add support for pluggable languages
Erik Bruchez: It may give implementors more confidence to move in this 
direction if we have something earlier; otherwise, they will wait 5 years 
before looking at it.
John Boyer: The scarey bit for me is XPath 2.0 in an XPath 1.0 processor 
even though it specifies a 1.2 processor. So maybe there is a versioning 
capability and it requires some pluggable module as Nicks says, not just 
functions, but other equipment such as XPath 2.0.
Erik Bruchez: XPath is a fundamental part of XForms so an attribute for 
that is fine for me. If you say XPath 2.0 is mandatory for XForms 2.0, and 
you don't have XForms 2.0 then it won't work anyway.
John Boyer: Absolutely, but it could be more generic: xpath-2.0, 
javascript, etc.
Mark Birbeck: [irc] But could also support JSON, for example. Perhaps my 
@hasFeature proposal from years ago?
Erik Bruchez: Can we quickly do this as a separate document under our 
John Boyer: We can double check with Steven, but my prior experience is 
that we can produce other documents in addition to the requirements.
Nick van: Or a note.
John Boyer: It would be nice to have the content first. The XML Signature 
WG produced a plethora of products: XML Canonicalization, Exclusive 
Canonicalization, and XPath Filter 2, which bears some relationship to our 
issue, of using another technology with our existing recommendation track.
Leigh Klotz: I like XPath 2.0 and Erik's proposal sounds like a good way 
to get people to look at it early.
John Boyer: No resolution, but an action to look at the module. I'm not 
sure we can backport it to 1.1 because of the Schema change for 
@hasFeature or whatever. Erik:
Action 2007-12-19.4: Erik Bruchez to investigate adding XPath 2.0 to 
XForms 1.2 in a modular way that encompasses adding other pluggable 
languages in the future.
John Boyer: OK, see you all in the new year.
* IRC Minutes
* Meeting Ends
Received on Wednesday, 19 December 2007 18:18:58 UTC

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