Re: Running a preprocessor from GPS?

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Thu, 30 Jul 2015 06:00:11 -0700 (PDT), EGarrulo wrote:

> On Thursday, July 30, 2015 at 1:22:36 PM UTC+2, Niklas Holsti wrote:
>> On 15-07-30 11:45 , EGarrulo wrote:
>>  > Exceptions in Ada cannot ... be chained
>> 
>> I'm not sure what you mean by "chained", but an Ada exception handler 
>> can either raise another exception, or re-raise the same exception, for 
>> handling at higher levels.
> 
> By "chained", I mean that a failure in an operation can
> cause a failure in the calling operation, and so on.  Let's
> imagine that the initialization of an application relies
> on reading a configuration file.  If the syntax of the 
> configuration file is not correct, then the routine that
> reads it will raise an exception, but this exception would
> be too low-level to be meaningful for the user.  Therefore,
> it makes sense to chain this exception to another higher-
> level exception that explains what the application was
> trying to do.  To the end user, this will appear as a chain
> of exceptions:
> 
> - INITIALIZATION_ERROR: The application failed to initialize;
> - CONFIGURATION_ERROR: The configuration failed;
> - BAD_FORMAT: The configuration file isn't formatted correctly;
> - SYNTAX_ERROR: The value of LEVEL is not of the expected type.
> 
> Basically, each exception in the chain answers the
> question "why?"  Now, if you report only one of those
> exceptions, then you lose context.  This is why you should
> be able to chain exceptions.  Of course, you could achieve
> a similar result by concatenating messages, but this way
> you would be performing manually what the language should
> have performed automatically.

exception
    when Error : Chain_Error =>
        raise Chain_Error with "Worse than " & Exception_Message (Error);
end;

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de