Compiling AFLEX 1.4a with Dec Ada 83 3.5-20 on Open VMS 7.1

Compiling AFLEX 1.4a with Dec Ada 83 3.5-20 on Open VMS 7.1

[singlespeeder]

I've got hold of the source for AFLEX 1.4a and want to compile it to run on
Open VMS 7.1

The compiler I have access to is DEC Ada 83 3.5-20.

As far as I can tell there are two things in the code that require
modification.

1) AFLEX 1.4a assumes that the Ada 95 package Ada.Command_Line is available.
2) AFLEX 1.4a assumes that the Ada 95 implementation of Text_IO is
available, and uses the file Standard_Error. It also generates a debug
scanner that uses Standard_Error.

I've addressed the first issue by writing a package VAX_Command_Line that
wraps starlet, and I just used that in place of Ada.Command_Line - I only
had to change two packages, both of which were documented in the manual.

I'm having more trouble with the second issue. In the lex specification for
the scanner I currently get around the scanner assuimg the presence of
Standard_Error by the following kludge in my lex specification. (Note that
AFLEX 1.4a only has two user defined sections, not 4 as in some manuals)

-- definitions
%%
-- rules
%%
-- user defined section copied before yylex
package foo is
    standard_error : text_io.file_type;
    function yylex return token;
end foo;
package body foo is
##
-- user defined section copied after yylex
begin
    text_io.create (file => standard_error,
        mode => out_file,
        name => lexer_error.txt);
end foo;

So my package foo declares it's own standard_error, which it creates when
the package is elaborated. It always does this even when I instruct AFLEX
not to generate a debug scanner - in which case I get an empty
lexer_error.txt file.

Is there a better way of writing my lex specification so that I don't have
to have this kludge, or am I going to have to poke around in the source of
Aflex? I don't want to do this because I don't want to then have to generate
a set of tests for  AFLEX to make sure I haven't screwed it up.

Nick

Re: Compiling AFLEX 1.4a with Dec Ada 83 3.5-20 on Open VMS 7.1

[Marin David Condic]

Not really addressign your question directly, but....  There is an Ada95
implementation for Alpha/VMS. I have not checked in a while, but look at the
GNAT FTP site and see if it is still there. I had it installed on an
Alpha/VMS platforma couple of years ago and it worked very well, supporting
all the DEC specific pragmas, etc. It would save you from having to hammer
together patches to go backwards to Ada83...

MDC
--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com
Web:      http://www.mcondic.com/


"singlespeeder" <singlespeeder@32sixteen.com> wrote in message
news:9bsm5c$khe$1@uranium.btinternet.com...
> I've got hold of the source for AFLEX 1.4a and want to compile it to run
on
> Open VMS 7.1
>
> The compiler I have access to is DEC Ada 83 3.5-20.
>
> As far as I can tell there are two things in the code that require
> modification.
>
> 1) AFLEX 1.4a assumes that the Ada 95 package Ada.Command_Line is
available.
> 2) AFLEX 1.4a assumes that the Ada 95 implementation of Text_IO is
> available, and uses the file Standard_Error. It also generates a debug
> scanner that uses Standard_Error.
>
> I've addressed the first issue by writing a package VAX_Command_Line that
> wraps starlet, and I just used that in place of Ada.Command_Line - I only
> had to change two packages, both of which were documented in the manual.
>
> I'm having more trouble with the second issue. In the lex specification
for
> the scanner I currently get around the scanner assuimg the presence of
> Standard_Error by the following kludge in my lex specification. (Note that
> AFLEX 1.4a only has two user defined sections, not 4 as in some manuals)
>
> -- definitions
> %%
> -- rules
> %%
> -- user defined section copied before yylex
> package foo is
>     standard_error : text_io.file_type;
>     function yylex return token;
> end foo;
> package body foo is
> ##
> -- user defined section copied after yylex
> begin
>     text_io.create (file => standard_error,
>         mode => out_file,
>         name => lexer_error.txt);
> end foo;
>
> So my package foo declares it's own standard_error, which it creates when
> the package is elaborated. It always does this even when I instruct AFLEX
> not to generate a debug scanner - in which case I get an empty
> lexer_error.txt file.
>
> Is there a better way of writing my lex specification so that I don't have
> to have this kludge, or am I going to have to poke around in the source of
> Aflex? I don't want to do this because I don't want to then have to
generate
> a set of tests for  AFLEX to make sure I haven't screwed it up.
>
> Nick
>
>

Re: Compiling AFLEX 1.4a with Dec Ada 83 3.5-20 on Open VMS 7.1

[Ted Dennison]

In article <9c1avq$mr9$1@nh.pace.co.uk>, Marin David Condic says...
>
>Not really addressign your question directly, but....  There is an Ada95
>implementation for Alpha/VMS. I have not checked in a while, but look at the
>GNAT FTP site and see if it is still there. I had it installed on an
>Alpha/VMS platforma couple of years ago and it worked very well, supporting
>all the DEC specific pragmas, etc. It would save you from having to hammer
>together patches to go backwards to Ada83...

There also used to be an Ada 83 port of lex/yacc floating around somewhere. That
cobweb over at http://www.adahome.com may actually be of some use for you. :-)

---
T.E.D.    homepage   - http://www.telepath.com/dennison/Ted/TED.html
          home email - mailto:dennison@telepath.com

Re: Compiling AFLEX 1.4a with Dec Ada 83 3.5-20 on Open VMS 7.1

[Charlie McCutcheon]

Marin David Condic wrote:

> Not really addressign your question directly, but....  There is an Ada95
> implementation for Alpha/VMS. I have not checked in a while, but look at the
> GNAT FTP site and see if it is still there. I had it installed on an
> Alpha/VMS platforma couple of years ago and it worked very well, supporting
> all the DEC specific pragmas, etc. It would save you from having to hammer
> together patches to go backwards to Ada83...
>

GNAT for OpenVMS Alpha still exists.  See
http://www.openvms.compaq.com/commercial/ada/gnat_hp.html and/or
http://www.gnat.com/ for more information.

Compaq Ada only has limited extensions for Ada 95.  I don't expect this to
change to help you any...

Charlie

Re: Compiling AFLEX 1.4a with Dec Ada 83 3.5-20 on Open VMS 7.1

[Marin David Condic]

What exactly do you mean by "extensions for Ada 95"? I used GNAT on an
Alpha/VMS platform & it supported the full Ada95 language. It had some
pragmas that were not in the standard that were put there to support old
DEC-Ada83 pragmas. (BTW: Perfectly legal, just in case someone wants to
start The Great DEC/Ada/Nonstandard/Failure Debate again. :-) There was
probably some support for DEC/Ada supplied packages that weren't in the
standard (Starlet comes to mind), but I never had to use that, so I don't
know for sure. (Again, a perfectly legal and reasonable thing to do.)
Most/all of that was done for compatibility with the Ada83 DEC compiler &
beyond that I don't know of any "extensions".

I think the original issue was one of trying to take some Ada95 code and
cobble it backwards to run on the DEC Ada83 compiler. Upgrading to Ada95
would likely solve the problems. I doubt there would be much need to get any
extensions made to the compiler to do that.

MDC
--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com
Web:      http://www.mcondic.com/


"Charlie McCutcheon" <charlie.mccutcheon@NOSPAMcompaq.com> wrote in message
news:3AF000FC.2E00D5F0@NOSPAMcompaq.com...

> Compaq Ada only has limited extensions for Ada 95.  I don't expect this to
> change to help you any...
>

Re: Compiling AFLEX 1.4a with Dec Ada 83 3.5-20 on Open VMS 7.1

[Marin David Condic]

O.K. Compaq bought DEC - thus inheriting the DEC Ada83 compiler. DEC had
contracted at some point with ACT to have GNAT ported to their hardware and
basically used this as their upgrade path from Ada83. (Hence GNAT was the
"official" DEC compiler at some juncture.) Did Compaq take the DEC Ada83
compiler and start upgrading it? If so, for what reason? (Seeing as how they
had Ada95 available.) Or is this some completely unrelated product? If it
doesn't target VMS, it doesn't seem to have much relevance to the original
problem, so I'm rather guessing that it must be derived from the original
DEC compiler.

MDC
--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com
Web:      http://www.mcondic.com/


"Larry Kilgallen" <Kilgallen@eisner.decus.org.nospam> wrote in message
news:u38o8Pk66$OW@eisner.encompasserve.org...
> He ascribed the "extensions for Ada 95" to "Compaq Ada".  That is the
> Ada83 implementation (nee DEC Ada (nee VAX Ada)) and has nothing to
> do with GNAT on Alpha VMS.
>

Re: Compiling AFLEX 1.4a with Dec Ada 83 3.5-20 on Open VMS 7.1

[Larry Kilgallen]

In article <9cp2to$gkf$1@nh.pace.co.uk>, "Marin David Condic" <marin.condic.auntie.spam@pacemicro.com> writes:
> What exactly do you mean by "extensions for Ada 95"? I used GNAT on an
> Alpha/VMS platform & it supported the full Ada95 language.

> "Charlie McCutcheon" <charlie.mccutcheon@NOSPAMcompaq.com> wrote in message
> news:3AF000FC.2E00D5F0@NOSPAMcompaq.com...
> 
>> Compaq Ada only has limited extensions for Ada 95.  I don't expect this to
>> change to help you any...

He ascribed the "extensions for Ada 95" to "Compaq Ada".  That is the
Ada83 implementation (nee DEC Ada (nee VAX Ada)) and has nothing to
do with GNAT on Alpha VMS.

At least one of those extensions in Compaq Ada is a slight variation
on bounded/unbounded string, added as a package rather than built into
the compiler.

Re: Compiling AFLEX 1.4a with Dec Ada 83 3.5-20 on Open VMS 7.1

[Marin David Condic]

Yes. That was basically my impression. DEC/Ada83 vs Gnat/Ada95. I don't
remember if DEC was in the business of directly selling a Gnat distribution
with/without any specific support - but I do remember their sales weenies
indicating that this was the upgrade path from Ada83. I basically got the
public distribution and had our IT dude install it & it worked fine.

When DEC was assimilated I figured Compaq would continue support for
whatever DEC did while migrating towards other products, until the last
vestiges of DEC withered away and were consigned to the dustbin of history.
I figured that the Ada83 compiler would go along for the ride. (pity - it
was a really great compiler and one of the very first descent quality Ada
implementations.) However, the Gnat library model was really a better idea
as was Ada95, so I didn't shed too many tears over it. About the only
incompatibility I tripped across in porting the code I was responsible for
was a difference of opinion on how to implement discriminated records. It
was not hard to find or fix, so the port was mostly painless. It was a real
testimony to the portability of Ada - I had Ada code that worked on PC/NT,
Sun/Unix and Alpha/VMS and the porting between the three platforms was
pretty much just a recompile and go. (Except for systems where we hooked
heavily to OS services or file formats I can't recall anything that didn't
just recompile & run with no bugs introduced.

MDC
--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com
Web:      http://www.mcondic.com/


"Larry Kilgallen" <Kilgallen@eisner.decus.org.nospam> wrote in message
news:A7+MNsS+DhZT@eisner.encompasserve.org...
> GNAT is officially recommended on VMS (Alpha only) by Compaq (nee DEC) for
> those who want Ada95.  It is not sold by Compaq, but they would be happy
to
> sell you one or more machines to run it on :-)
>

Re: Compiling AFLEX 1.4a with Dec Ada 83 3.5-20 on Open VMS 7.1

[Jeffrey Carter]

Larry Kilgallen wrote:
> 
> At least one of those extensions in Compaq Ada is a slight variation
> on bounded/unbounded string, added as a package rather than built into
> the compiler.

I hate to be pedantic (actually, I LOVE to be be pedantic, but don't
tell anyone), but Ada.Strings.Bounded and Ada.Strings.Unbounded are
technically packages, not built into the compiler.

--
Jeffrey Carter

Re: Compiling AFLEX 1.4a with Dec Ada 83 3.5-20 on Open VMS 7.1

[Larry Kilgallen]

In article <9cpd6o$kgg$1@nh.pace.co.uk>, "Marin David Condic" <marin.condic.auntie.spam@pacemicro.com> writes:
> O.K. Compaq bought DEC - thus inheriting the DEC Ada83 compiler. DEC had
> contracted at some point with ACT to have GNAT ported to their hardware and
> basically used this as their upgrade path from Ada83. (Hence GNAT was the
> "official" DEC compiler at some juncture.) Did Compaq take the DEC Ada83
> compiler and start upgrading it? If so, for what reason? (Seeing as how they
> had Ada95 available.) Or is this some completely unrelated product? If it
> doesn't target VMS, it doesn't seem to have much relevance to the original
> problem, so I'm rather guessing that it must be derived from the original
> DEC compiler.

Compaq Ada = DEC Ada
DEC Ada = VAX Ada (except that it also does Alpha)

Those are official Compaq (nee DEC) products, available for license today.
They implement Ada83.

GNAT is officially recommended on VMS (Alpha only) by Compaq (nee DEC) for
those who want Ada95.  It is not sold by Compaq, but they would be happy to
sell you one or more machines to run it on :-)

> 
> MDC
> --
> Marin David Condic
> Senior Software Engineer
> Pace Micro Technology Americas    www.pacemicro.com
> Enabling the digital revolution
> e-Mail:    marin.condic@pacemicro.com
> Web:      http://www.mcondic.com/
> 
> 
> "Larry Kilgallen" <Kilgallen@eisner.decus.org.nospam> wrote in message
> news:u38o8Pk66$OW@eisner.encompasserve.org...
>> He ascribed the "extensions for Ada 95" to "Compaq Ada".  That is the
>> Ada83 implementation (nee DEC Ada (nee VAX Ada)) and has nothing to
>> do with GNAT on Alpha VMS.
>>
> 
> 
> 
-- 
==============================================================================
Great Inventors of our time: Al Gore -> Internet; Sun Microsystems -> Clusters
==============================================================================

Re: Compiling AFLEX 1.4a with Dec Ada 83 3.5-20 on Open VMS 7.1

[Larry Kilgallen]

In article <9cq06u$qmp$1@nh.pace.co.uk>, "Marin David Condic" <marin.condic.auntie.spam@pacemicro.com> writes:
> Yes. That was basically my impression. DEC/Ada83 vs Gnat/Ada95. I don't
> remember if DEC was in the business of directly selling a Gnat distribution
> with/without any specific support - but I do remember their sales weenies
> indicating that this was the upgrade path from Ada83. I basically got the
> public distribution and had our IT dude install it & it worked fine.
> 
> When DEC was assimilated I figured Compaq would continue support for
> whatever DEC did while migrating towards other products, until the last
> vestiges of DEC withered away and were consigned to the dustbin of history.
> I figured that the Ada83 compiler would go along for the ride.

Remember those stories about long-lived Ada projects ?
Some of them don't want to switch compilers 1/4 of the
way through their life-cycle.

==============================================================================
Great Inventors of our time: Al Gore -> Internet; Sun Microsystems -> Clusters
==============================================================================

Re: Compiling AFLEX 1.4a with Dec Ada 83 3.5-20 on Open VMS 7.1

[Marin David Condic]

Yes, that's true. But typically you freeze on a specific version of the
compiler out of fear that any changes made to it will only screw things up.
(Or at least require huge amounts of regression testing!) Maybe you take
maintenance releases that fix known bugs, but the minute you start buying
into new features, you might as well be taking a new compiler.

Of course there are always portability issues that might keep you from
moving to a different brand of compiler. (Hopefully Ada/Software
Engineering/Common Sense got the pain down to a minimum.) I see your point,
but I'm wondering what is in it for Compaq? If it were me, I'd provide
maintenance support to keep my existing customers happy, but I'd put any
new-feature $$$ into extending the next generation product. (That being
Ada95/Gnat in this context.) Continuing to enhance DEC/Ada83 with Ada95
features only creates a divergence similar to Win95 & WinNT - which can be a
*real* expensive hobby.

Now if someone wants to simply pay me for modifications on a cost-plus
basis, I'll modify that compiler until it parses Eiffel, Smalltalk, Java,
Snobol, Cobol, Lisp, Perl, DCL, JCL and even Befunge. (And for your
convenience, all in the same file!) It just wouldn't seem like a wise thing
to do if it were *my* money. :-)

MDC
--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com
Web:      http://www.mcondic.com/



"Larry Kilgallen" <Kilgallen@eisner.decus.org.nospam> wrote in message
news:Igp6s1LxpQMC@eisner.encompasserve.org...
> In article <9cq06u$qmp$1@nh.pace.co.uk>, "Marin David Condic"
<marin.condic.auntie.spam@pacemicro.com> writes:
> Remember those stories about long-lived Ada projects ?
> Some of them don't want to switch compilers 1/4 of the
> way through their life-cycle.
>

Re: Compiling AFLEX 1.4a with Dec Ada 83 3.5-20 on Open VMS 7.1

[Gautier of my Mollin]

Marin David Condic:

>Continuing to enhance DEC/Ada83 with Ada95
>features only creates a divergence similar to Win95 & WinNT - which
>can be a *real* expensive hobby.

OK, so which one would you abandon: Win95 or WinNT ?

__________________________________________
Gautier  --  http://www.diax.ch/users/gdm/

_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com

Re: Compiling AFLEX 1.4a with Dec Ada 83 3.5-20 on Open VMS 7.1

[Larry Kilgallen]

In article <9crr5a$h37$1@nh.pace.co.uk>, "Marin David Condic" <marin.condic.auntie.spam@pacemicro.com> writes:
> Yes, that's true. But typically you freeze on a specific version of the
> compiler out of fear that any changes made to it will only screw things up.
> (Or at least require huge amounts of regression testing!) Maybe you take
> maintenance releases that fix known bugs, but the minute you start buying
> into new features, you might as well be taking a new compiler.

It depends on the "new feature" in question.  One was the ability to
run on the lastest processors (EV6 at the time).  Nothing for customers
to change in their code.

> Of course there are always portability issues that might keep you from
> moving to a different brand of compiler. (Hopefully Ada/Software
> Engineering/Common Sense got the pain down to a minimum.) I see your point,
> but I'm wondering what is in it for Compaq? If it were me, I'd provide
> maintenance support to keep my existing customers happy, but I'd put any

That is what they do.

The string package is an abberation.

Re: Compiling AFLEX 1.4a with Dec Ada 83 3.5-20 on Open VMS 7.1

[Charlie McCutcheon]

Sorry, I apparently too vague and confused people.  Thanks, Larry for stepping in.

Compaq Ada is still supported, and is at Ada 83 plus some packages for Ada 95 features.  Not many however.  No
language syntax changes for 95, nor will there ever likely be any.

We still fix bugs reported for Ada 83, and I still hear from customers...

For new features, or Ada 95 support, we recommend GNAT, which works on OpenVMS Alpha.

Charlie
Compaq Ada

Re: Compiling AFLEX 1.4a with Dec Ada 83 3.5-20 on Open VMS 7.1

[Don McCabe]

The "official" Ada compiler from Compaq is still the Ada83 compiler from 
DEC and is now supported as a "mature" product which means no new 
functionality will be developed but maintenance support is available for 
programs committed to the compiler. Also, there was indeed a port of 
ACT's GNAT which was started by DEC and is "promoted" by Compaq as an 
alternative compiler. All maintenance/upgrades/etc to the GNAT port are 
strictly through ACT. The port did give users of Compaq Ada83 a very 
easy port to the ACT Ada95 compiler because it provided all the required 
pragmas and even the extended system package. We still use both 
compilers on our Alpha machines.

Marin David Condic wrote:

> O.K. Compaq bought DEC - thus inheriting the DEC Ada83 compiler. DEC had
> contracted at some point with ACT to have GNAT ported to their hardware and
> basically used this as their upgrade path from Ada83. (Hence GNAT was the
> "official" DEC compiler at some juncture.) Did Compaq take the DEC Ada83
> compiler and start upgrading it? If so, for what reason? (Seeing as how they
> had Ada95 available.) Or is this some completely unrelated product? If it
> doesn't target VMS, it doesn't seem to have much relevance to the original
> problem, so I'm rather guessing that it must be derived from the original
> DEC compiler.
> 
> MDC
> --
> Marin David Condic
> Senior Software Engineer
> Pace Micro Technology Americas    www.pacemicro.com
> Enabling the digital revolution
> e-Mail:    marin.condic@pacemicro.com
> Web:      http://www.mcondic.com/
> 
> 
> "Larry Kilgallen" <Kilgallen@eisner.decus.org.nospam> wrote in message
> news:u38o8Pk66$OW@eisner.encompasserve.org...
> 
>> He ascribed the "extensions for Ada 95" to "Compaq Ada".  That is the
>> Ada83 implementation (nee DEC Ada (nee VAX Ada)) and has nothing to
>> do with GNAT on Alpha VMS.
>> 


-- 
Donald P. McCabe        mailto:donald.p.mccabe@boeing.com
Embedded Software Designer V    Phone: (480) 891-6135
The Boeing Company - Mesa    FAX  : (480) 891-5280