Re: Structured exception information

[Georg Bauhaus <bauhaus@futureapps.de>]

On Sun, 2007-01-28 at 08:18 -0500, Stephen Leake wrote:
> Stephen Leake <stephen_leake@stephe-leake.org> writes:
> 
> > However, I have yet to see an _actual_ implemention of View that is
> > not equivalent to "write this string to a device". So I do _not_
> > anticipate changing that implementation.
> 
> I have to take this back, partly. Ray Blaak posted an example where
> View would do:
> 
> Write Short_Description to immediate display device

Our office printer has four LEDs, two in green, two in
red. In addition, there are some defined blinking
sequences. On top of the chassis, there is a label with
a legend explaining a number of these combinations.

So the "exception strings" are external to the program
supposedly running inside the printer. I agree that there
are no natural language strings that can usefully be sent
to the 4 LEDs. But in this example we have a reporting
facility that is easily modified by replacing the label
with explanatory text in Spanish, say. Now,

> Write Detailed_Description to log device

if there was an occurrence of Paper_Jam, and
if there is a way to communicate with this printer
using same cable connection, the handler can also construct
information more useful to service personnel, or to service
machinery using a communications protocol.
 The point is that all of these views will use the
same information (ID of the device part that reports failure,
kind of failure, ...). Depending on what View is being used,
what reporting language, what communications channel,
etc., typed exception information could be used to construct
a suitable object depending on the display.