Re: Is this expected behavior or not

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

On Fri, 22 Mar 2013 13:10:18 -0700 (PDT), Shark8 wrote:

> On Friday, March 22, 2013 10:07:51 AM UTC-6, Dmitry A. Kazakov wrote:
>> On Thu, 21 Mar 2013 18:27:22 -0500, Randy Brukardt wrote:
>> 
>>> But I still think you are trying too hard to avoid run-time checks.
>> 
>> If I weren't, I would use Perl, not Ada. I favor Ada exactly because it
>> gives me static checks. It is sad to see Ada drifting towards run-time /
>> dynamic-typing junk.
> 
> Runtime-typing and dynamic-typing are two different things, no?

Possibly, depends on how you define it. Anyway all boils down to run-time
checks (faults) vs. compile-time checks (errors/bugs). A failed run-time
check is a program state to anticipate. More such checks you do, more
states you have, more difficult it becomes to design tests covering these
states, or just to keep in mind that such states exist and are reachable.

I don't buy run-time checks unless *proven* that compile-time check would
be impossible to have. And this is not an optimization issue.

> Ada has always had run-time checking:

Sure.

[ It is trivial to put up an example where no compile-time check can exist,
e.g.

   function Puzzle return Positive is
   begin
      if HALT (p) then
         return -1;
      else
         return 1;
      end if;
   end Puzzle;

It is a halting problem to prove that Puzzle does not raise
Constraint_Error. ]

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