Re: ANN: Kickstarter for beginning work on a new open-source Compiler

[dirk@feles.cs.kuleuven.be. (Dirk Craeynest)]

In article <87txaqd28v.fsf@ludovic-brenta.org>,
Ludovic Brenta  <ludovic@ludovic-brenta.org> wrote:
>"J-P. Rosen" <rosen@adalog.fr> writes:
>> FYI, Gnat was always written in Ada, bootstrapped from the Alsys
>> compiler.
>
>Really?  I always thought it was bootstrapped from Ada/Ed?

Yes, really.  The first successful bootstrap of GNAT, using the Alsys
Ada 83 compiler, was announced at the Ada-Europe conference in June
1993 in Paris (by Robert Dewar, IIRC).

And no, it wasn't by using Ada/Ed, as that was an interpreter
and didn't generate any object code or executable.  Ada/Ed did
generate some high-level intermediate representation, which was
then interpreted.

>So what's
>the relationship between Ada/Ed and GNAT, apart from both being
>developed at New York University?

You got it: both are implementations of Ada, developed at NYU.

Ada/Ed was intended as a kind of operational specification of Ada,
and was developed in parallel with the Ada 83 language.

Some more trivia...

The first Ada/Ed version was written in SETL (a programming language
based on sets), which was also interpreted.  Hence two levels
of step-by-step execution: SETL interprets Ada/Ed, which in turn
interprets your Ada program.  Clearly the result was "rather slow".

I still remember a tiny Towers-of-Hanoi demo-program we wrote, with
a basic ASCII-graphics display for the 3 stacks of disks.  With 5
disks, it took two nights and a full day to run!  (I must still have
the output file somewhere...).

Later on a second version of Ada/Ed was made available, which was
written in C.  That one was already more suitable for teaching purposes
(which was what we used it for at the Leuven university at that time).

End of trivia... ;-)

Dirk
Dirk.Craeynest@cs.kuleuven.be (for Ada-Belgium/-Europe/SIGAda/WG9 mail)

*** 19th Intl.Conf.on Reliable Software Technologies - Ada-Europe'2014
*** June 23-27, 2014 **** Paris, France **** http://www.ada-europe.org