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Your help is needed to better define XForms Basic

From: Micah Dubinko <MDubinko@cardiff.com>
Date: Thu, 18 Apr 2002 15:36:00 -0700
Message-ID: <E840F0B7E6189547BDB91DA8BF2228AB28C40D@csmail.cardiff.com>
To: "'www-forms@w3.org'" <www-forms@w3.org>
Greetings XForms enthusiasts,

The XForms Working Group recently published a Last Call Working Draft and
asked for public comment. A number of the comments involved the description
of XForms Basic, requesting a better and easier-to-implement definition.

To solve these problems and address the Last Call comments, the Working
Group has formed an XForms Basic Task Force. The goals of the task force are
to:

* Identify specific areas that are trouble spots in XForms Basic
* Come up with specific proposals to fix the trouble spots
* Seek public feedback on both of the above
* Make final recommendations to the Working Group


1. HARD DATA

We conducted a poll among mobile device vendors within the Working Group,
rating each feature on the following scale:

1 - trivial to implement
2 - minor problems -- I could support 4-8 total things this complex
3 - medium -- I could support 2 or 3 things this complex
4 - very challenging -- I could support at most 1 thing this complex
5 - showstopper -- I can't implement XForms with this feature

Participants were asked to rate High-level XForms features on this scale.
The averaged results:

Schema Structures
1.0 xsi:type
5.0 all other parts of Schema Structures

Schema Datatypes
2.7 Basic
3.7 Everything

XPath
3.0 Streaming XPath, decimal
4.0 Streaming XPath, IEEE
4.7 Full XPath

UI
2.3 All UI except <repeat> stuff
3.3 All UI including <repeat> stuff

Constraints
1.0 Omit all "computed expression" constraints
3.5 Omit only "calculate"
4.0 All constraints

XForms Actions
4.0 All XForms Actions

A second round of questioning covered greater detail:

Constraints
1.7 type
1.7 readonly
1.3 required
1.7 relevant
3.0 calculate
1.7 constraint (isValid)
2.0 maxOccurs
2.0 minOccurs
1.0 p3ptype

Events
2.7 The dispatch Element
2.3 The refresh Element
2.3 The recalculate Element
2.3 The revalidate Element
1.7 The setfocus Element
1.7 The load Element
1.7 The setvalue Element
1.7 The send Element (submitInstance)
1.7 The reset Element
2.0 The script Element
2.3 The message Element
2.0 The action Element

Events associated with Repeat
3.0 The setindex Element (setRepeatCursor)
3.0 The insert Element
3.0 The delete Element

Events associated with Switch
2.0 The toggle Element


2. PROPOSALS

Based on the above data, the task force is offering the following initial
proposals., each of which can be accepted or rejected independently. We
welcome additional proposals as well.


XML SCHEMA - XForms Basic should include the defined subset of Datatypes,
and xsi:type and nothing more from Structures. At no point would "Structural
Validation" (or any other flavor of XML Schema validation) of instance data
take place.

XPATH - XForms Basic should use only a subset of XPath 1.0, by removing the
following:
  - no "|" union operator on node-sets
  - remove all axes except: child, attribute, namespace
  - only position(), self (.),  and attribute (@foo) tests allowed in
predicates

IEEE - XForms Basic should allow decimal arithmetic implementations of XPath
(the XPath specification uses IEEE floating point). This may produce
slightly different calculations in some cases, but that is an implementation
trade-off. (Note this is present in the Last Call Working Draft)

USER INTERFACE - XForms Basic should omit repeating structures (<repeat> and
<itemset>), as well as <insert> and <delete> XForms Actions.

CONSTRAINTS - XForms Basic should remove 'calculate' and all other computed
properties. (Note that this would severely reduce the power of XForms, and a
number of participants expressed concern over making such a large cut.)

SCRIPT - XForms Basic should not have any means to connect to scripting
languages, including the <script> XForms Action and the IDL method
getInstanceDocument().

EVENTS I - XForms Basic should omit the <dispatch> XForms Action.

EVENTS II - XForms Basic should omit the <refresh>, <recalculate>, and
<revalidate> XForms Actions.

3. REQUEST FOR FEEDBACK

Please comment on any of these proposals by responding to www-forms@w3.org.
Note that this is a subscription list, so please send an initial message
with the subject "subscribe" if you are not already subscribed. The comment
period ends at midnight GMT on Sunday, May 5, 2002.

Thanks!

Micah Dubinko
Editor, XForms 1.0
Received on Thursday, 18 April 2002 18:36:07 GMT

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