Re: function-available gone?

Hi Elliotte,

The function was removed in the Dec. 2001 draft, and the following month 
the Jan. 2002 draft then added the mechanism currently in use.  The 
attribute had a longer name in that draft, but instead of having that 
function, the model element declares a 'functions' attribute that lists 
all of the extension functions needed to run the form (those available 
from the core library in XPath 1.0 or the XForms spec need not be listed 
as they are not extensions to the XForms library).

Having the XPath function would have required the following additional 
machinery:

1) the form author would have to set up an event handler to run the XPath 
that called the function-available() function.
2) The form author would have needed a way to generate a processing halt 
if the function returned false. 

By comparison, the current method allows the XForms processor to determine 
very early in the lifecycle of the document (i.e. before running any 
XPaths) whether or not the necessary functions are available.  It is also 
a much easier way to make such a statement compared to the function method 
outlined above.

Cheers,
John M. Boyer, Ph.D.
STSM: 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





Elliotte Harold <elharo@metalab.unc.edu> 
07/10/2007 06:53 PM

To
John Boyer/CanWest/IBM@IBMCA
cc
www-forms@w3.org
Subject
Re: function-available gone?






John Boyer wrote:
> 
> Hi Elliotte,
> 
> Could you give me a pointer to a WD that has this function?
> 

http://www.w3.org/TR/2001/WD-xforms-20010828/slice6.html

section 6.6.1


-- 
Elliotte Rusty Harold  elharo@metalab.unc.edu
Java I/O 2nd Edition Just Published!
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