On 20–24 July 1970 a working conference was arranged by the International Federation for Information Processing (IFIP) to discuss the problems of implementing the language,[1] a small team from the Royal Radar Establishment (RRE) attended to present their compiler, written by I. F. Currie, Susan G. Bond,[2] and J. D. Morrison.
The compiler was distributed at no charge by International Computers Limited (ICL) on behalf of the Royal Radar Establishment (RRE).
The proceduring coercion was dropped, and the form mode : expression was redefined as a procedure denotation, casts being indicated by an explicit VAL symbol: Code that had a valid use for call by name (for example, Jensen's device) could simply pass a procedure denotation: In the version of the language defined in the revised report these changes were accepted, although the form of the cast was slightly changed to mode (expression).
In the original language the VOID mode was represented by an empty mode: The ALGOL 68-R team decided to use an explicit VOID symbol in order to simplify parsing (and increase readability): This modification to the language was adopted by the ALGOL 68 revised report.
In the revised report on ALGOL 68 formal bounds were also removed, but the FLEX indication was moved in position so it could be include in formal declarers: In ALGOL 68 code can be run in parallel by writing PAR followed by a collateral clause, for example in: the procedures producer and consumer will be run in parallel.
The effects of this restriction were rarely important and, if necessary, could be worked around by using a cast to provide a strong context at the required point in the program.
As ALGOL 68-R was implemented on a machine with 6-bit bytes (and hence a 64 character set) this was quite complex and, at least initially, programs had to be composed on paper punched tape using a Friden Flexowriter.
ALGOL 68-R was delivered with its own library format and utilities which allowed sharing of modes, functions, variables, and operators between separately compiled segments of code which could be stored in albums.
Machine instructions could be written inline, inside CODE ... EDOC sections and the address manipulation operators INC, DEC, DIF, AS were added.
[15] An example, using a George peri operation to issue a command: A copy of the ALGOL 68-R compiler, runnable under the George 3 operating system emulator, by David Holdsworth (University of Leeds), is available, with source code, under a GNU General Public License (GPL).