Re: Booch: iterator invalidation

[porton@ex-code.com (Victor Porton)]

In article <u65v268c4.fsf@gsfc.nasa.gov>,
	Stephen Leake <stephen.a.leake.1@gsfc.nasa.gov> writes:
> Simon Wright <simon@pushface.org> writes:
> 
>> > It also would be great to have the debug version of Booch, checking
>> > validity of iterators and raising an exception. With GNAT it can be
>> > done as in C by #ifdef/#endif preprocessor directives (assigning a
>> > long (may be 64, 128, or 256 bytes) counter incrementing on each
>> > invalidation to each container and analogous counters to iterators
>> > and comparing these counters).
>> 
> I believe "pragma Assert" is supported by all major Ada compilers at
> this time; that could be used to give a good "debug version".

I'm not about asserting but about records which have or don't have
a component dependingly on whether it is the debuging version. Can
variant records be used for this without lost of space efficiency?

type T_Internal(Debug: Boolean) is
  record
    -- ...
    case Debug is
      when True =>
        -- ... additional debugging stuff
      when others =>
        null;
    end case;
  end record;

type T is T_Internal(Use_Debug); -- Use_Debug is a Boolean _constant_

Will this not bring "additional debugging stuff" in the release
version (when Use_Debug=False)?