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attributes, software architecture, CC/PP and accessibility

From: Scott Luebking <phoenixl@netcom.com>
Date: Tue, 1 Feb 2000 14:04:25 -0800 (PST)
Message-Id: <200002012204.OAA22088@netcom.com>
To: w3c-wai-gl@w3.org

In a previous posting, Wendy asked me to look at CC/PP amd see
if it is in sync with my ideas.

Before going into that discussion, I thought it might be helpful to
talk a little about attributes/preferences and software architecture.

An arrangement that I've found helpful in software architecture is to
provide for external attributes/preferences and internal attributes/preferences.
The external attributes/preferences are known outside of the program
while internal attributes/preferences are known only inside of the program.
There are several advantages to this arrangement.  One is that the names
used for the external attributes/preferences can be renamed, aliased, etc
and the internal attributes/preferences can be left the same.  Only
the mapping of the external attributes/preferences to internal
attributes/preferences need be changes.  This arrangement also allows
for external attributes/preferences to be specified from different sources
using names relevant to the source without needing to change the
internal attributes/preferences.

In this arrangement, values from CC/PP would be seen as external
attributes/preferences from the CC/PP source.  Also, a web page
could be provided for specifying user preferences using attributes/preferences
which need not have the same names as CC/PP.  The names would
be more relevant to the purpose of the web page where the names
from CC/PP would be more generic.

Assuming that a web site provides an ability to store a user's
preferences from a previous visit, a user preference page and the
handling for CC/PP, the following steps would probably occur
when a user visits the web site:

    1.  set internal attributes/preferences from defaults

    2.  set internal attributes/preferences from stored user preferences

    3.  query user agent for CC/PP information

    4.a.  if no CC/PP information is returned, display a greeting web page
	  with a link to user preferences web page which has a list
	  of external attributes/preferences relevant to the web site

    4.b.  if CC/PP information is returned, set the internal attributes/preferences
	  from the external attributes/preferences provided by the
	  CC/PP.  then display a greeting web page with a link
	  to user preferences web page which has a list of external
	  attributes/preferences relevant to the web site.  (This web
	  page will let a user over-ride values provided by CC/PP
	  as might be needed for the particular session.  It is also
	  highly useful for debugging.)

In this organization, CC/PP should identify major classes of disability,
e.g. "blind", "upper arm limitations".  The application would then translate
these external attributes/preferences into possible internal
attributes/preferences like "use simple format" or "include fast
section navigation".  (Ideally, the user preference web page would allow
the user to turn off all features relevant to a disability or
let the user pick and choose which disability features to include.)

As near as I can tell, CC/PP isn't providing information about
a person's disability.

Received on Tuesday, 1 February 2000 17:06:55 UTC

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