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Need to re-work Chapter 2 substantively?

From: <AndrewWatt2001@aol.com>
Date: Wed, 12 Dec 2001 04:39:52 EST
Message-ID: <13d.60d58f8.29487fe8@aol.com>
To: www-forms@w3.org
CC: xforms@yahoogroups.com
I guess since the XForms WD is almost at Last Call WD it is probably time to 
raise an issue which has been niggling me for several versions of the spec. 

I think the division of Purpose / Presentation / Data is a little wooly.

There are two issues, from my perspective:
1. The examples in Chapter 2 are not ideally structured and need to be 
re-drafted
2. I suspect the Purpose / Presentation / Data structure itself may be 
fundamentally flawed or redundant

I feel a little like the wee boy daring to suggest the Emperor has no 
clothes, so I hope you will be patient as I try to explain my concerns.

Let me deal with the more superificial concern first. In the table in Chapter 
2 of the WD under the "Purpose" header we see terms like "Time Card" and 
"Order Form". It seems to me that those **in terms of purpose** (assuming it 
has its natural meaning) would be more appropriately expressed as "Collection 
of worker time data" and "Collection of order data". That sort of term/phrase 
is a "purpose", as I understand the term. Terms like "time card" and "order 
form" are actually presentations (or include an element of presentation) in 
my view.

When you come to use phrases like those I have suggested under the Purpose 
heading you tend to find that it is a litany of "[whatever type of] data 
collection". And the data is listed under the Data heading.

Which brings me to my deeper concern. Is the three way division of Purpose / 
Presentation / Data needed at all?

For the scenarios which readily come to mind I find the three way division 
working out as:
1. Purpose - collecting X data
2. Presentation - [potentially multiple] 
 - order form on desktop PC
 - order form on palm computer etc etc
3. Data - X data (maps usually - always??? - one to one with item 1, Purpose).

The obvious scenarios, at least to me, work out as
1 purpose : multiple presentations : 1 set of data
So if purpose and data map one to one do we really need a three way structure?

The other possible scenario is:
1 purpose: multiple presentations : multiple sets of data (attenuated for wee 
devices)
But is that "one" XForms model at all? Or, when we have multiple sets of data 
don't we, when we think about the situation more precisely, have multiple 
purposes?

As an example we might have:
full personal info collection : desktop PC presentation : full personal info
abbrev personal info collection : mobile phone form : abbrev personal info

Again, in this type of scenario where the purpose (carefully spelled out) 
differs the data set seems to move in parallel - again with a one to one 
relationship.

I hope I have been able to express why I have doubts about the current 
presentation of Chapter 2 and the underlying structure fairly clearly. If WG 
members have scenarios where we have
1 or many purposes : multiple presentations : 1 set of data 
then I guess we may actually need the three way Purpose / Presentation / Data 
division.

If not, is simplicity and clarity not better served by a two way Presentation 
/ Data Model view?

I would like to suggest that the WG considers that a two dimensional 
Presentation / Data Model explanation/structure is more concise and perhaps 
better represents the potential advantages which XForms brings to the Web.

Andrew Watt                                                
Received on Wednesday, 12 December 2001 04:39:57 GMT

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