An extensive revision of ALGOL 60 by Adriaan van Wijngaarden et al. ALGOL 68 was discussed from 1963 by Working Group 2.1 of IFIP. Its definition was accepted in December 1968.
ALGOL 68 was the first, and still one of very few, programming languages for which a complete formal specification was created before its implementation. However, this specification was hard to understand due to its formality, the fact that it used an unfamiliar metasyntax notation (not BNF) and its unconventional terminology.
One of the singular features of ALGOL 68 was its orthogonal design, making for freedom from arbitrary rules (such as restrictions in other languages that arrays could only be used as parameters but not as results). It also allowed user defined data types, then an unheard-of feature.
It featured structural equivalence; automatic type conversion (“coercion”) including dereferencing; flexible arrays; generalised loops (for-from-by-to-while-do-od), if-then-else-elif-fi, an integer case statement with an ‘out’ clause (case-in-out-esac); skip and goto statements; blocks; procedures; user-defined operators; procedure parameters; concurrent execution (par-begin-end); semaphores; generators “heap” and “loc” for dynamic allocation. It had no abstract data types or separate compilation.
- Algol 60 revised
algol 60 revised language (Or “Revised ALGOL 60”) A revision of Algol 60 which still lacked standard I/O. [“Revised Report on the Algorithmic Language ALGOL 60”, Peter Naur ed, CACM 6(1):1-17 (Jan 1963)]. [Sammet 1969, p.773]. (1995-01-25)
- Algol 68 revised
algol 68 revised language A significant simplification of ALGOL 68. [“Revised Report on the Algorithmic Language ALGOL 68,” A. Van Wijngaarden et al, Acta Informatica 5:1-236, 1975, also Springer 1976, and SIGPLAN Notices 12(5):1-70, May 1977]. (1995-05-03)
- Algol 68-r
algol 68-r language A restriction of ALGOL 68 permitting one-pass compilation, developed at the Royal Signals Radar Establishment, Malvern, Worcester, UK in April 1970. Identifiers, modes and operators must be declared before use. There is no automatic proceduring and no concurrency. It was implemented in ALGOL 60 under GEORGE 3 on an ICL 1907F. [“ALGOL […]
- Algol 68c
algol 68c language A variant of ALGOL 68 developed by S. Bourne and Mike Guy of Cambridge University in 1975 and used as the implementation language for the CHAOS OS for the CAP capability computer. ALGOL 68C was ported to the IBM 360, VAX/VMS and several other platforms. (1995-05-02)