Re: C++ Standardization (was: Once again, Ada absent from DoD SBIR solicitation)

[dewar@merv.cs.nyu.edu (Robert Dewar)]

Bob Duff said

"If you were the last company on Earth using Ada, then you would not have
a competetive advantage -- you would be stuck shovelling money into the
last Ada compiler on Earth.  And it would be buggy and inefficient, and
the latest and greatest configuration management tools wouldn't work
with it."

Unnecessarily pessimistic I think, in several respects. Sure this may be
true if you are talking about a proprietary compiler built and maintained
in a vacuum, but in fact it takes relatively little use of Ada to support
the continued development of GNAT, and the reason that is achievable is
that we maintain open systems standards precisely so that the "latest
and greatest configuration management tools" will work with minimial
or even zero effort.

We are committed to GNAT becoming the best compiler for any language, period.
Sure it would be nice if Ada really took off and became super succesful,
but our business plan does NOT depend on this hapenning, and GNAT can
continue to prosper and improve without depending on huge amounts of
resources. 

I think this is important. People have mentioned reently that top
management often worries about the future of Ada. If your only
response is to depend on the hope that Ada will become wildly
successful, then if I was in that position, I would ban Ada use
immediately. It is not that I am sure this will not happen, it is
that I certanly cannot say I am sure it will happen, and relying
on super sucess for Ada is far too risky.

It is much more convincing to be able to demonstrate that there will
be at least one usable high quality technology that allows the
potential of Ada 95 to be realized REGARDLESS of whether or not
Ada succeeds in grabbing a huge market share. Ironically, this
assurance that such success is not required is one thing that will
greatly help to increase the chances of such success.

I can't speak for any other Ada vendors, but Ada Core Technologies is
very optimistic about its future, and we see ourselves as being around
for the long term, and succeeding in continuing to improve the quality
of the compiler. Shortly we will release 3.07 which has some substantial
improvements. In fact, why not? here is a preview of the new features:

   GNAT now checks for the case of a body file present when the spec does
   not require a body. GNAT always diagnosed the error when the body was
   compiled, but if only the spec was compiled, the suspicious body was
   ignored. The presence of a body file when no body is allowed is now
   considered an error in Ada 95 mode, and a warning in Ada 83 mode.

   Packed arrays with bounds depending on a discriminant now work correctly

   The DEC pragmas have been implemented. Those of interest to GNAT ports
   in general are as follows (see below for full documentation)
       Common_Object
       Component_Alignment
       Export_Function
       Export_Object
       Export_Procedure
       Export_Valued_Procedure
       Import_Function
       Import_Object
       Import_Procedure
       Import_Valued_Procedure
       Suppress_All

   The DEC attributes have been implemented. Those of interest to GNAT ports
   in general are as follows (see below for full documentation)
       Bit
       Machine_Size
       Null_Parameter
       Type_Class

   Attribute Mechanism_Code allows determination of the parameter passing
   mechanism chosen by GNAT, as possibly controlled by the Import, Export
   and C_Pass_By_Copy pragmas.

   Pragma Extend_System allows transparent extension of package System to
   accomodate definitions from other implementations of Ada.

   Machine code insertions have been completely implemented. A new section
   in gnatinfo.txt describes the use. Both code statements as such, and
   also intrinsic calls are available. The latter allow interspersing
   machine instructions in Ada code. Inlining of machine code procedures
   is fully supported.

   The pragma C_Pass_By_Copy is implemented in a manner that is completely
   compatible with the Intermetrics implementation of this pragma.

   The default mechanism for passing records to foreign convention subprograms
   is now by-reference. This can be modified by either use of one of the
   DEC extended Import/Export pragmas, or by use of the C_Pass_By_Copy pragma.

   Further extended support for representation clauses, including more cases
   of misaligned fields, and non-standard layouts. Record representation
   clauses no longer require that the position of all fields be specified.

   Pragma Error_Monitoring has been removed. This pragma was not used and had
   a number of conceptual and implementation problems.

And of course that is 3.07, we are hard at work on 3.08, and have already
added many interesting new capabilities that will show up in 3.08. Not
listed in the above list is the general improvements in reliability and
performance that come from steady work on these aspects.

GNAT is still in its infancy if we take a long term view, which we do!
We have many ideas for improving its performance and realiability and
functionality, and fully expect to see these ideas realized in coming
years.