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CPL
:
,
,
,
et al.Firstappeared1963;63years agoInfluenced by
Influenced
CPL (Combined Programming Language) is a
multi-paradigm programming language
developed in the early 1960s. It is an early ancestor of the
via the
and
languages.
CPL
was developed initially at the Mathematical Laboratory at the
as the "Cambridge Programming Language" and later published jointly between Cambridge and the
Computer Unit as the "Combined Programming Language" (CPL was also nicknamed by some as "Cambridge Plus London"
or "Christopher's Programming Language"
).
,
and others were involved in its development. The first paper describing it was published in 1963, while it was being implemented on the
at Cambridge and the
at London.
It was heavily influenced by
, but instead of being extremely small, elegant and simple, CPL was intended for a wider application area than scientific calculations and was therefore much more complex and not as elegant as ALGOL 60. CPL was a big language for its time, and it attempted to go beyond ALGOL to include industrial process control, business data processing, and possibly some early command line games.
CPL was intended to allow low-level programming and high level abstractions using the same language.
However, CPL was only implemented very slowly. The first CPL compiler was probably written around 1970,
but the language never gained much popularity and seems to have disappeared without trace sometime in the 1970s.
(for "Basic CPL", although originally "Bootstrap CPL") was a much simpler language based on CPL, intended primarily as a
language, particularly for writing
;
it was first implemented in 1967, prior to CPL's first implementation. BCPL then led, via
, to the popular and influential
.
The function MAX as formulated by
:
Max(Items, ValueFunction) = value of § (Best, BestVal) = (NIL, -∞) while Items do § (Item, Val) = (Head(Items), ValueFunction(Head(Items))) if Val > BestVal then (Best, BestVal) := (Item, Val) Items := Rest(Items) ̸§ result is Best ̸§ The closing section block symbol used here (̸§) is an approximation of the original symbol, in which the cross stroke is vertical. This is available in Unicode as §⃒ but does not display correctly on many systems.
It is thought that CPL was never fully implemented in the 1960s, existing as a theoretical construct with some research work on partial implementations.
Peter Norvig has written (for Yapps, a Python
) a simple CPL to
translator for modern machines.
Fundamental Concepts in Programming Languages
Barron, D. W.; Buxton, J. N.; Hartley, D. F.; Nixon, E.; Strachey, C. (1 August 1963).
. The Computer Journal. 6 (2): 134–143.
:
.
.
"Clive Feather on CPL and BCPL"
. Lysator.liu.se. Retrieved 18 August 2013.
Jensen, Richard (9 December 2020).
""A damn stupid thing to do"—the origins of C"
. Ars Technica. Retrieved 10 December 2020.
Yadav, P. (2005).
. Discovery Publishing House.
.
(23 August 2011).
"Prescient but Not Perfect: A Look Back at a 1966 Scientific American Article on Systems Analysis"
. Scientific American Blog Network. Retrieved 10 December 2020.
Mitchell, John C.;
(2003).
Concepts in Programming Languages
. Cambridge University Press.
.
(1 January 1968).
. The Computer Journal. 11: 26–30.
:
.
(2013).
. Computer Conservation Society. Retrieved 3 May 2023.
Norvig, Peter.
"Complete Annotated Checkers Program"
. norvig.com. Retrieved 11 June 2021.
How BCPL evolved from CPL, Martin Richards, 2011
Collected papers of Christopher Strachey, section pertaining to CPL, archived at the Bodleian Library, Oxford;
D.W. Barron, J.N. Buxton, D.F. Hartley, E. Nixon, and C. Strachey.
The Computer Journal6:2:134-143 (1963), available
.
J. Buxton, J.C. Gray, and D. Park.
CPL Elementary Programming Manual, Edition II (Cambridge)
(1966).
University of London Institute of Computer Science and The Mathematical Laboratory, Cambridge.
(1966).