ADA compilers

ADA compilers

[Patty]

I am trying to find an ADA compiler for ADA83 for a Pentium/RedHat
Enterprise Linux 3 operating system platform, but have not been able to
locate one so far. Anyone know of one??

Re: ADA compilers

[Pascal Obry]

"Patty" <patricia.l.addiss@honeywell.com> writes:

> I am trying to find an ADA compiler for ADA83 for a Pentium/RedHat
> Enterprise Linux 3 operating system platform, but have not been able to
> locate one so far. Anyone know of one??

Why Ada83, are you porting an application ?

Have a look at GNAT. Part of GCC and commercial support available from
AdaCore. http://www.adacore.com. I'm sure there is some other compilers
for GNU/Linux I'll let other answer...

Pascal.

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Re: ADA compilers

[Patty]

Yes, we are trying to port an existing application.  I have looked at
GNAT, but they only have ADA95.

Re: ADA compilers

[Dmitry A. Kazakov]

On 3 Jun 2005 12:12:01 -0700, Patty wrote:

> Yes, we are trying to port an existing application.

Egh, how to port Ada 83 to Ada 95 without Ada 95?

>  I have looked at GNAT, but they only have ADA95.

1. There should be no problem to port Ada 83 code to Ada 95.
Incompatibilities are rather minor.

2. AFAIK, GNAT has "-gnat83" switch for Ada 83 legacy code.

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

Re: ADA compilers

[Björn Lundin]

2005-06-03 kl. 21.21 skrev Dmitry A. Kazakov:

> On 3 Jun 2005 12:12:01 -0700, Patty wrote:
>
>> Yes, we are trying to port an existing application.
>
> Egh, how to port Ada 83 to Ada 95 without Ada 95?

Porting to another OS perhaps?

The OP is looking for and ADA compiler for linux, not an Ada 95 
compiler.

/Björn

Björn Lundin
bnl at spray dot se

Re: ADA compilers

[Jeff C]

Patty wrote:
> Yes, we are trying to port an existing application.  I have looked at
> GNAT, but they only have ADA95.
> 

The issues involved with an update from Ada 83 to Ada 95 are <<= any 
issues you will run into with simply porting code from one compiler/os 
to another.

If the existing code makes use of a lot of vendor specific packages and 
it does not encapsulate it well, this will be a bit of work.

In any case if I were doing a bid (and I've done lots of them) the port 
from Ada 83 to Ada 95 would probably not even how up in the last digit 
compared to any other issues associated with the port.


What can be a bit more difficult (situation I have been in for a long 
time) is when you need the same (or mostly the same) codebase to be 
backwards compatible with the old compiler for some time. The only 
trouble in this case is just verifying from time to time that you did 
not "leak" any ada 95 features into your code base.

In any case I've got about 150K SLOC of Ada 83 that I also use with an 
Ada 95 compiler (with Ada 83 being the primary compiler still for a 
variety of reasons) and I've only got 1 file that is branched to make 
the Ada 83 work with the Ada 95 compiler because it is Ada 95 (note 
there are 5 or 6 other branched files but these are branched due to some 
vendor specific library issues or other areas that are due to vendor 
differences and not Ada language revision differences).

Re: ADA compilers/ difference between 83 and 95

[Chris Albertson]

--- Patty <patricia.l.addiss@honeywell.com> wrote:

> Yes, we are trying to port an existing application.  I have looked at
> GNAT, but they only have ADA95.
> 
> _______________________________________________
> comp.lang.ada mailing list
> comp.lang.ada@ada-france.org
> http://www.ada-france.org/mailman/listinfo/comp.lang.ada
> 


Chris Albertson
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  Cell:   310-990-7550
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Re: ADA compilers

[Keith Thompson]

"Patty" <patricia.l.addiss@honeywell.com> writes:
> Yes, we are trying to port an existing application.  I have looked at
> GNAT, but they only have ADA95.

Most valid Ada 83 programs are valid Ada 95 programs with the same
semantics.  Most of the exceptions (such as using new keywords as
identifiers) are easy to fix.

Try compiling the application with GNAT (or with any Ada 95 compiler).
You're likely to run into more problems going from one compiler to
another than going from Ada 83 to Ada 95, especially if the program
uses any compiler-specific features -- and you're going to have to fix
those problems anyway.

Since Ada 83 compilers are, for the most part, no longer being
maintained, you might not be able to find one that works with a newer
operating system.

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
San Diego Supercomputer Center             <*>  <http://users.sdsc.edu/~kst>
We must do something.  This is something.  Therefore, we must do this.

Re: ADA compilers

[Björn Lundin]

2005-06-03 kl. 21.12 skrev Patty:

> Yes, we are trying to port an existing application.  I have looked at
> GNAT, but they only have ADA95.
>
We have ported a fairly large system from Ada83 to Ada 95 (Ie using an 
Ada 95 compiler on Ada83 code)
with hardly no problems. The things to watch out for is if you have 
variable names that
are the same as the new reserved words that Ada 95 brings. Ie you cant 
have a variable called 'aliased' since
that is a reserved word now.

We are using Gnat now, and had troble with some applications due to 
circular dependencies,
with the resukt that the Gnat compiler refused to link the application. 
The 'difficult' application contained heavy
use of tasking, in combination of a great deal of generic packages. The 
old compiler said OK, and so did other
Ada 95 compilers. Minor rewrite solved it.

A BIG difference with Gnat and other compilers are the way the Ada 
library a
is handled. We used it a lot, having several libraries in the same 
level, but not able to see each other.
ie
global
     level2-1
     level2-2
        level3
     level2-3

where the ones on level2 could all see global, but not each other. 
Level3 could see level2-2 and global but not the others

Of course, having different packages, with the same name, in all 
level2's is common in our system.
Tcl-script reading flat file'repository' based on current working 
directory, and
use of environment variables ADA_INCLUDE_PATH and ADA_OBJECT_PATH made
it possible to make it work, without having to use several projectfiles.

This was the
biggest challege

Then of course, packages using vendors spcifics, as how to get the 
command line, tasking policies
etc will differ.

Another thing to watch out for, if tasking is inviolved, is how the old 
compiler created tasks.
Is it run by the os like threads or locally in the runtime? This 
changes the way you can interact
with blocking io. We got a big boost using Gnat, because it made it 
possible to use
blocking io, instead of polling.

This was on Aix, but compiled and linked and tested (very very little) 
on Linux and mac os X as well

/Björn

Björn Lundin
bnl at spray dot se

Re: ADA compilers

[Jeffrey Carter]

Patty wrote:
> Yes, we are trying to port an existing application.  I have looked at
> GNAT, but they only have ADA95.

I have used GNAT to develop Ada-83 code. In fact, I had to do so again 
only a couple of weeks ago. The -gnat83 switch turns GNAT into an Ada-83 
compiler.

Note that it's Ada, a woman's name, not the American Dental Association.

-- 
Jeff Carter
"Oh Lord, bless this thy hand grenade, that with it thou
mayst blow thine enemies to tiny bits, in thy mercy."
Monty Python and the Holy Grail
24

Re: ADA compilers

[Martin Krischik]

Patty wrote:

> I am trying to find an ADA compiler for ADA83 for a Pentium/RedHat
> Enterprise Linux 3 operating system platform, but have not been able to
> locate one so far. Anyone know of one??

Well you can use gnat with the "-gnat83" option.

Martin

-- 
mailto://krischik@users.sourceforge.net
Ada programming at: http://ada.krischik.com

Re: ADA compilers/ difference between 83 and 95

[Chris Albertson]

Sorry aout the last message hadno text. Here is is again


I'm curious, will ada83 programs not compile under ada95?

If there is a problem where is it?  What part of the language spec
changed in an incompatable way?  Yes I do have some old code that
currently runs on a VAX and I'm like to get it running on a
Duel Xeon system under Solaris 10.  I assumed only minor work 
would be required.  I think gnat has a switch to disallow
the '95 syntax.  

I would not want to use an old compiler, so much work has been
done in recent years it would be a shame not to take advantage
of it



Chris Albertson
  Home:   310-376-1029  chrisalbertson90278@yahoo.com
  Cell:   310-990-7550
  Office: 310-336-5189  Christopher.J.Albertson@aero.org
  KG6OMK

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Re: ADA compilers/ difference between 83 and 95

[Keith Thompson]

Chris Albertson <chrisalbertson90278@yahoo.com> writes:
> Sorry aout the last message hadno text. Here is is again
>
> I'm curious, will ada83 programs not compile under ada95?
>
> If there is a problem where is it?  What part of the language spec
> changed in an incompatable way?
[snip]

The biggest change is the new reserved words that Ada 83 programs
might use as identifiers.  (That's actually not a very common problem,
as far as I know).

The best way to find out is to try compiling the code with an Ada 95
compiler and read the error messages.

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
San Diego Supercomputer Center             <*>  <http://users.sdsc.edu/~kst>
We must do something.  This is something.  Therefore, we must do this.

Re: ADA compilers/ difference between 83 and 95

[Jeffrey Carter]

Chris Albertson wrote:

> If there is a problem where is it?  What part of the language spec
> changed in an incompatable way?  Yes I do have some old code that
> currently runs on a VAX and I'm like to get it running on a
> Duel Xeon system under Solaris 10.  I assumed only minor work 
> would be required.  I think gnat has a switch to disallow
> the '95 syntax.  

I've compiled lots of Ada-83 code with Ada-95 compilers and never had a 
serious problem. The important thing is that the code was designed to be 
portable in the first place. If you have lots of compiler or platform 
dependencies in your code, it becomes harder.

-- 
Jeff Carter
"Oh Lord, bless this thy hand grenade, that with it thou
mayst blow thine enemies to tiny bits, in thy mercy."
Monty Python and the Holy Grail
24

Re: ADA compilers/ difference between 83 and 95

[Marin David Condic]

I've ported a LOT of VAX/VMS (DEC) Ada 83 to Gnat Ada95 and never 
encountered anything that was a problem between the two language 
versions. There may be some obscure corner-case rules that trigger 
incompatibilities but in practical use, I just never encountered any. I 
did get some warnings about using the package ASCII and maybe that's as 
close to an incompatability as I've seen.

Mostly, I had some issues where different compiler writers had different 
views of what to implement. A few instances where DEC Ada handled 
unconstrained types differently from Gnat Ada and, of course, some 
vendor specific implementation details once in a while (like packages 
that may or may not be there because they are vendor supplied) but two 
observations: I don't recall anything that got past the compiler that 
ended up being an issue - so the compiler is your friend here. I don't 
recall anything that didn't run just fine when it finally linked. I 
*have* had problems when porting between two *different* platforms - 
mostly with byte-sex issues, but that has been minimal. (Ada 95 has some 
features to help you out making byte-sex issues portable as well, but I 
have not delved into them lately)

Porting even a large body of Ada code (if reasonably well written to be 
portable - no fair throwing in compiler-specific things in every unit & 
expecting zero effort) even across platforms has not been much of an 
issue in my experience. I've done a few hundred thousand lines in a 
couple of days & had it up and running - but it was *my* code so I was 
familiar with it and I have usually had the wisdom to isolate any 
compiler specifics. Even a stranger's code being moved across platforms 
and to a different language standard ought to be minimal fuss.

MDC


Chris Albertson wrote:
> Sorry aout the last message hadno text. Here is is again
> 
> 
> I'm curious, will ada83 programs not compile under ada95?
> 


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