MustUnderstand Module - Well I would like to :)

The MustUnderstand Module in Chapter 3.4 of the 20020821 XForms WD needs 
further and more complete explanation.

There is no use case given (perhaps that should have been in the XForms 
Requirements document). So what are the realistic scenarios where it is 
"critical" for an XForms processor to understand elements from another 

If an XForms attribute, must be added to an element from another namespace 
what are the implications (negative, I assume) for the (naive?) idea of 
"write once, run everywhere" that I had of XForms?

How can a developer or XForms author be sure that an XForms processor 
"understands" an element in a foreign namespace? What precisely does 
"understand" mean in this context? How is the "understanding" confirmed?

Why is a failure to "understand" a "fatal error"? Why is there no fallback 
option for processing?

If I am trying to use a browser with an XForms processor that doesn't 
understand the "critical" element then am I, as a user, simply left with an 
error message and a total inability to access ANY version of the form?

BTW, there is no definition of "fatal error" that I could find in the XForms 
WD. Of course I have a general idea of what a "fatal error" is but shouldn't 
it be stated clearly what an XForms processor should do when it encounters 

Andrew Watt

Received on Friday, 30 August 2002 05:19:27 UTC