ALGOL 68RS

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ALGOL 68RS is an implementation of ALGOL 68. Other implementations of ALGOL 68.



ALGOL 68RS from RSRE was a portable compiler system written in ALGOL 68RS (bootstrapped from ALGOL 68R), and implemented on a variety of systems including the ICL 2900/Series 39, Multics and DEC VAX/VMS.

The language was based on the Revised Report, but with similar subset restrictions to ALGOL 68R. This compiler survives in the form of an Algol68-to-C compiler aka ELLA ALGOL 68.

Modules[edit]

ALGOL 68RS allow the programmer the ability of creating modules, these can be used by other programs and also allowed separate compilation.

Syntax: <lang algol68>PROGRAM [ (holelist ) ] progtitle [ CONTEXT holename IN progtitle ] [ USE uselist ] enclosed clause FINISH</lang> <lang algol68>DECS dectitle CONTEXT holename IN progtitle [ USE uselist ] decsbody KEEP keeplist FINISH</lang>

Example[edit]

PROGRAM (thinking, displaying) chess
BEGIN
  MODE PIECE = STRUCT(...);
  [12]PIECE pieces;
  ...
  HERE thinking(PIECE, pieces, BOARD, game);
  ...
  HERE displaying(PIECE, pieces, BOARD, game);
  ...
END</lang>

<lang algol68>PROGRAM thinkmodule
CONTEXT thinking IN chess
...
FINISH

An entire program can thus be composed of pieces of other modules, particularly if a hole contains a sub-hole (eg displaypiece), then this hole can in-turn be pulled into the composition.

Example: <lang algol68>PROGRAM abc COMPOSE game(thinking=thinkmodule, displaying=displayingmodule(piece=displaypiece)) FINISH</lang>