Re: C/C++ cheaper than Ada?? how? Re: Ada 200X

Re: C/C++ cheaper than Ada?? how? Re: Ada 200X

[Sam Harbaugh, Palm Bay, Florida]

re: cheaper - This spring the project I am on was directed by the DoD
customer to switch from Ada95 to C++.  The customer perceives that C++ is
less expensive than Ada95.  I will wait at least a year to give an opinion
on relative cost.  If you haven't looked at C++ in a while look again, the
draft standard ANSI/ISO C++ has new features.

re: Ada 200X - I suggest: 1) Recognize that it is a multilingual world,
accomodate other popular languages. The program I am on is a C++ project
but actually there are 13 programming languages to be used. 2) Recognize
that it is a multi-architecture world, accomodate interpretive systems and
systems which don't admit programs which have runtime systems.

my 2 cents - worth every penny

Re: C/C++ cheaper than Ada?? how? Re: Ada 200X

[Robert Dewar]

<<re: Ada 200X - I suggest: 1) Recognize that it is a multilingual world,
accomodate other popular languages. The program I am on is a C++ project
but actually there are 13 programming languages to be used. 2) Recognize
that it is a multi-architecture world, accomodate interpretive systems and
systems which don't admit programs which have runtime systems.
>>

I find this puzzling. Ada 95 is the ONLY language to systematically
accomodate other languages, and it goes very far in this respect. If you
have specific suggestions for improvements in this area, fine, but to
somehow suggest that Ada 95 dos NOT accomodate other popular languages
seems bizarre.

Ada is perfectly interoperable with interpretive systems. Usually these
days, that is a code word for Java. The fact that two separate vendors
of Ada compilers are providing Ada compilers that generate JBC should
be an indication that this is not a problem.

As for "don't admit programs which have runtime systems". There is nothing
about Ada that requires that every Ada program needs a runtime system. Indeed,
GNAT provides a capability, which we call GNORT (GNAT with No RUntime) that
does what it says. Allows the compilation of programs with absolutely no
runtime. Obviously this means that there are restrictions in the subset
that can be used, but it is a pretty big subset (much bigger than SPARKI
for example), and in the Java Byte Code context, GNAT will accomdoate
the Ravenscar tasking model, again with zero runtime.

So I really don't see what the quote above is asking for, and I certainly
don't see any substantial issues to be addressed in Ada 200X here. Again,
if there are specific suggests rather than what appear to be ill-informed
generalizations, then that would be very helpful!

Robert Dewar
Ada Core Technologies

Re: C/C++ cheaper than Ada?? how? Re: Ada 200X

[Larry Kilgallen]

In article <dewar.900353937@merv>, dewar@merv.cs.nyu.edu (Robert Dewar) writes:

> As for "don't admit programs which have runtime systems". There is nothing
> about Ada that requires that every Ada program needs a runtime system. Indeed,
> GNAT provides a capability, which we call GNORT (GNAT with No RUntime) that
> does what it says. Allows the compilation of programs with absolutely no
> runtime. Obviously this means that there are restrictions in the subset
> that can be used,

Not so obvious to some of us.  Please elaborate.

Larry Kilgallen

Re: C/C++ cheaper than Ada?? how? Re: Ada 200X

[ak]

kilgallen@eisner.decus.org (Larry Kilgallen) writes:

> In article <dewar.900353937@merv>, dewar@merv.cs.nyu.edu (Robert Dewar) writes:
> 
> > As for "don't admit programs which have runtime systems". There is nothing
> > about Ada that requires that every Ada program needs a runtime system. Indeed,
> > GNAT provides a capability, which we call GNORT (GNAT with No RUntime) that
> > does what it says. Allows the compilation of programs with absolutely no
> > runtime. Obviously this means that there are restrictions in the subset
> > that can be used,
> 
> Not so obvious to some of us.  Please elaborate.

I guess all features related to tasking (protected types, the task type)
are gone. Exceptions need moderate run time system support, so maybe they
are gone too (?)

-Andi

Re: C/C++ cheaper than Ada?? how? Re: Ada 200X

[Larry Kilgallen]

In article <m3btqs39lg.fsf@fred.muc.de>, ak@muc.de writes:
> kilgallen@eisner.decus.org (Larry Kilgallen) writes:
> 
>> In article <dewar.900353937@merv>, dewar@merv.cs.nyu.edu (Robert Dewar) writes:
>> 
>> > As for "don't admit programs which have runtime systems". There is nothing
>> > about Ada that requires that every Ada program needs a runtime system. Indeed,
>> > GNAT provides a capability, which we call GNORT (GNAT with No RUntime) that
>> > does what it says. Allows the compilation of programs with absolutely no
>> > runtime. Obviously this means that there are restrictions in the subset
>> > that can be used,
>> 
>> Not so obvious to some of us.  Please elaborate.
> 
> I guess all features related to tasking (protected types, the task type)
> are gone. Exceptions need moderate run time system support, so maybe they
> are gone too (?)

Well I didn't take "no run time" to mean "no operating system",
but even if it does, an Ada compiler could emit the necessary
instructions as part of the image to do tasking.

I am not saying it is cost-effective for a particular market
situation, but it is not a technical impossibility.

Are the GNORT restrictions just pragmatics, or are there technical
limits?

And by "no runtime" is it meant "no operating system" ?

Larry Kilgallen

Re: GNORT

[Markus Kuhn]

Robert Dewar wrote:
> As for "don't admit programs which have runtime systems". There is nothing
> about Ada that requires that every Ada program needs a runtime system. Indeed,
> GNAT provides a capability, which we call GNORT (GNAT with No RUntime) that
> does what it says. Allows the compilation of programs with absolutely no
> runtime.

How is this activated in GNAT? Do I just have to write something like

  pragma Restrictions(No_Exceptions, Max_Tasks => 0);

and the run-time system is gone?

Markus

-- 
Markus G. Kuhn, Security Group, Computer Lab, Cambridge University, UK
email: mkuhn at acm.org,  home page: <http://www.cl.cam.ac.uk/~mgk25/>

Re: GNORT

[Robert Dewar]

Markus asks

<<How is this activated in GNAT? Do I just have to write something like

  pragma Restrictions(No_Exceptions, Max_Tasks => 0);

and the run-time system is gone?
>>

this = GNORT


No, it is a special pragma (pragma No_Runtime)
(it is equivalent to a set of restrictions, plus does some other things!)

Re: C/C++ cheaper than Ada?? how? Re: Ada 200X

[Dr Richard A. O'Keefe]

Sam Harbaugh, Palm Bay, Florida wrote:
> If you haven't looked at C++ in a while look again, the
> draft standard ANSI/ISO C++ has new features.

Which will, of course, be useless in *portable* programs until 3 to
5 years after the standard is finalised, if the history of C89 is
any guide.

As things are right now, a student here developed a really snazzy
package on system X using "C++" compiler Y and gave it to me on a
system Z disc, but the "C++" compiler W on that system choked and
died on it.  That really is the typical C++ experience these days.
One hopes that the eventual existence of (a screamingly complex)
standard (still lacking a lot of useful Ada stuff) will change
things, but as I'm _still_ waiting for one particular vendor to
support something that has been pretty much unchanged in C++ drafts
for several years now, I wouldn't hold your breath.
 
> re: Ada 200X - I suggest: 1) Recognize that it is a multilingual world,
> accomodate other popular languages.

Ada 95 _already_ recognised that, in a far more effective way than
any other programming language standard yet in existence.  (Mind you,
there isn't an _official_ interface between Ada and REXX or Visual
Basic, but neither is there an official C++ interface to those things.)
There _is_ an Ada CORBA binding...