Re: Good Ada Style For Impossible Actions?

[Dr Nancy's Sweetie <kilroy@elvis.rowan.edu>]

Jeffrey Carter wrote, in reply to a question about when to use exceptions
and functions for testing error conditions:
> It sounds as if you could have mouse events outside the proper window
> at any time, so such an event would not be exceptional. So having a
> function would probably be a good idea.
>
> But if you use the function and still get a mouse event outside the
> proper window, you should also have an exception to indicate that.

If the function tries to compute a logical address for an invalid
mouse position, a CONSTRAINT_ERROR will be raised because the logical
position will be outside its valid range.

Is there a good heuristic for "raise your own exception" and "don't
clutter up the exception namespace"?


Darren Provine ! kilroy@elvis.rowan.edu ! http://www.rowan.edu/~kilroy
"C++ is like jamming a helicopter inside a Miata and expecting some
 sort of improvement." -- Drew Olbrich