Re: New tools and old exceptions

[Jeff Carter <carter@spam.innocon.com>]

Robert C. Leif, Ph.D. wrote:
> 
> From: Bob Leif, Ph.D.
> To: Comp.Lang.Ada
> 
> Many of us need all of the help that we can get. Ada.Exceptions has a
> function Exception_Information(X: Exception_Occurrence) return string;
> Exception_Occurrence is limited private and no simple information is given
> on how to call Exception_Occurrence as an argument based on a name such as
> Constraint_Error.
> From the error messages that I have been generating, Constraint_Error is an
> exception not an Occurrence.
> Therefore how does one
> Exception
> When Constraint_Error =>
> obtain the  Exception_Information on the Constraint_Error?
> I am posting this to Comp.Lang.Ada; since, I do not believe that this is a
> GNAT problem.
> 
> I would also like to note for the text book authors, that describing in
> detail how to maximize the information available in the Ada exception
> handler would be appreciated by the students and other readers.
> 
> Thank you.
> Bob Leif

Check out ARM 11.2, which defines an exception handler:

exception_handler ::=
         when [choice_parameter_specification:] exception_choice {|
exception_choice} =>
            sequence_of_statements

So you'd want something like

exception -- Block_Name
when C_E : Constraint_Error =>
   -- Something using Exception_Information (C_E):
   Text_Io.Put_Line (Item => Ada.Exceptions.Exception_Information (C_E)
);
... -- Other handlers
end Block_Name;
-- 
Jeff Carter  PGP:1024/440FBE21
Auntie-spam reply to; try ( carter @ innocon . com )
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