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Re: The message action is for messages, not arbitrary dialogs

From: John Boyer <boyerj@ca.ibm.com>
Date: Tue, 9 Jan 2007 18:24:03 -0800
To: mark.birbeck@x-port.net
Cc: www-forms@w3.org, www-forms-request@w3.org
Message-ID: <OFD4737411.A81137D3-ON8825725F.000C568F-8825725F.000D3362@ca.ibm.com>
Hi Mark,

Yes, thanks, and ditto :-)

I didn't disagree with rich messages.  All manner of enriched text 
could/should be available through host language constructs.

For me it breaks when the "rich" in "rich message" becomes so rich that it 
isn't a message anymore.  Because then message isn't a base class for 
whatever you are ending up with.

As you'll see in my response to Leigh, we have to say something about the 
semantics of message because it has to do something, but I don't think we 
say more than is necessary.  It is a display-only device.  This is no 
different than claiming that the output element is for display only.  You 
say that message is "something that can appear and disappear" whereas I 
claim it is "a message that can appear and disappear".  Moreover, the 
content model for message was defined to be only chardata and output 
elements, not repeats.  So, at the XForms level, a message is a simple 
textual string created by concatenating char data with the results of 
output elements evaluated at the time the message action is invoked.   The 
host language is free to add host language constructs that help beautify 
that text.  But form controls are not text. 

Finally, note that by erratum, the material relating help to message was 

John M. Boyer, Ph.D.
STSM: Workplace Forms Architect and Researcher
Co-Chair, W3C Forms 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

"Mark Birbeck" <mark.birbeck@x-port.net> 
Sent by: www-forms-request@w3.org
01/09/2007 02:57 PM
Please respond to

Re: The message action is for messages, not arbitrary dialogs

Hi John,

First, I hope you had a good break, and all the best for 2007.

> And, in any case, the whole issue remains orthogonal to the issue of 
what markup
> is expected to function interoperably within an xforms message.  The 
> schema does *not* include *any* host language markup in a message.  Host
> language authors are encouraged to add host language  constructs, but 
this does
> not in my view mean that they are allowed to add *all* host language 
> everywhere since doing so violates the definition of the construct 

I can see what you're trying to do, but I worry about being so
prescriptive, and I disagree that allowing rich messages goes against
the 'definition' of 'message'.

In my view, a message should be seen as more akin to a 'base class'
that has fairly clearly defined behaviour, but no claim can be made
about the semantics. It is something that 'appears' at some point, and
then depending on the value of @level, it will either disappear
automatically, or it requires the user to make it disappear. Beyond
that there is little more you can say about 'message', and in this it
is not unlike switch/case.

One reason I make the point about it being a base class that defines
*behaviour*, is that in XForms, 'help' is defined in terms of
'message'. In many help systems the help page you look at can do all
sorts of things, like have a tree view of contents, allow you to
search for help topics, and so on. If you start saying that the
semantics of 'message' are that it does not contain form controls then
that would preclude making 'help' behave in any other way than the
limited way that you are suggesting 'message' does.

But if you say that a message is simply something that appears and
disappears--i.e., it is defined by its behaviour, rather than its
purpose--then 'help' can nicely layer semantics onto 'message', but
retain the functionality.

> It is pretty clear that the host language constructs to be added are 
those that assist
> in diplaying a better message to the user (like bold, font changes, 
etc).  Other uses
> of UIInline might allow more constructs as appropriate to the situation.

I'd also worry about defining 'message' as something that can't take
form controls. For example, surely repeat, group and switch/case are
useful inside a 'message'? And once they are accepted as useful
(indeed, necessary) ways of creating rich responses for users, then
it's difficult to see what is gained by preventing other controls from
appearing in a message.

You could insist that they don't appear, but then you're left with
very basic messages, and you would also need to come up with a
*semantic* definition of 'message' that justifies this limitation.
Saying that messages are only 'one way' obviously does not rule out
using repeat, etc.. so that would not be good enough. And as it
happens, since in the approach I am advocating the action of the
'message' in and of itself does not return any data, then even
including a handful of input controls does not prevent the message
from being regarded as 'one way'.

(I should clarify that in formsPlayer you could have XForms, SVG and
MathML inside a 'message', and I see nothing in the spec that prevents



Mark Birbeck
x-port.net Ltd.

e: Mark.Birbeck@x-port.net
t: +44 (0) 20 7689 9232
w: http://www.formsPlayer.com/
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Received on Wednesday, 10 January 2007 02:24:23 UTC

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