Re: Algol68 compiler ? (Andy Pryor)
23 Feb 1996 18:20:13 -0500

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From: (Andy Pryor)
Newsgroups: comp.compilers
Date: 23 Feb 1996 18:20:13 -0500
Organization: Praxis plc, Bath, UK
References: 96-02-236 96-02-240 96-02-253
Keywords: algol68 (Arthur Chance) writes:
> Does anyone know what happened to the Algol 68RS system? AFAIR, this
> was written at RRE (RSRE, DRA - the place keeps changing its name)
> Malvern here in the UK as a successor to A68R, and it was written
> specifically to be portable.

Roger Barnett <> writes:
> The implementation of this compiler was, I think, a joint development
> between RSRE and Oxford University - the first version ran on an ICL
> system.

The South West Universities Regional Computer Centre (SWURCC) at the
University of Bath were also involved in its development, and supported it on
behalf of ICL for a number of years.

SWURCC also wrote a version for Multics, funded by Honeywell.

> I don't know who were selling the other platform versions, but I seem
> to recall that both Praxis in Bath and Rex Thompson in Farnham had
> some involvement. IIRC, Praxis had a compiler which generated C code,
> but that part of the company was split off around the time Praxis were
> taken over (anyone spotted a common theme here ? :) ); I have no
> information on its current status.

The systems development group at SWURCC, including the compiler
people, were split off to form Praxis. Praxis were funded by RSRE/DRA
to produce an ALGOL 68RS to C translator ("ctrans") in order to port
the ELLA (hardware description language) compiler and simulator to Sun
Sparc and Apollo workstations.

Praxis Electronic Design (which looked after ELLA, amongst other
things) was split off and sold, but went bust after a couple of years.
DRA decided then to make ELLA public domain, and funded some more work
from Praxis (ie me) to improve the portability of Ctrans and its
generated code, and to make it ANSI C compliant. DRA now own the
rights, and have made Ctrans publically available as part of their
ELLA distribution.

This has been discussed recently in comp.lang.misc, and this is what I posted
there (thanks to Richard O'Keefe for encouraging me to look in this group):

Trevor Jenkins said:

> Please somebody tell me and Pat Knight that a free and
> freely-available compiler exists somewhere out there.

An ALGOL 68 to C converter ("ctrans") is freely available as part of the
public domain ELLA (hardware description language) package from DRA Malvern in

The program is itself written in ALGOL 68, so the package contains a SunOS
Sparc binary (or a set of generated C files) to get you bootstrapped.

Ctrans is a portable ALGOL 68 compilation system that allows Algol 68
programs to be compiled and run on most systems for which an ANSI C
compiler is available.

The system consists of these components
    - Algol 68 to C translator (a68toc)
    - C header files providing type definitions and support macros required by
            the generated C code
    - run-time support library including garbage-collected heap allocator
    - an ALGOL 68 prelude library that provides interfaces to XPG3-compatible
            operating system facilities (note that these interfaces are not the same
            as the ALGOL 68 standard prelude defined in the Revised Report).

Ctrans can be easily ported to most systems that possess an ANSI C
compiler (e.g. gcc), and an XPG3 standard C library.

The heap management system works best on virtual memory systems, but
can be made to work in other environments.

The translator is based on the portable ALGOL 68 RS front-end
implemented by RSRE (now DRA) and therefore accepts all standard RS
extensions to the language (with a few exceptions).
Andy Pryor
Praxis Critical Systems 20 Manvers St, BATH, BA1 1PX, UK Tel:+44 1225 739257/444700 Fax:+44 1225 739281

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