Combined Programming Language
Encyclopedia
CPL was a multi-paradigm
programming language
, that was developed in the early 1960s.
and the University of London
Computer Unit during the 1960s hence CPL gained the nickname "Cambridge Plus London". The collaborative effort was responsible for the "Combined" in the name of the language (previously, the name was Cambridge Programming Language). D. W. Barron
and Christopher Strachey
were involved (for others see paper). In 1963 (when the paper was published) it was currently being implemented on the Titan Computer
at Cambridge and the Atlas Computer
at London.
It was heavily influenced by ALGOL 60
, 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. CPL attempted to go beyond ALGOL to include industrial process control and business data processing, among other things. CPL was also 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 about 1970, but the language never gained much popularity and seems to have disappeared without trace sometime in the 1970s.
A later language based on CPL, called BCPL
(for Basic CPL, although originally Bootstrap CPL) was a much simpler language intended primarily as a systems programming language, particularly for writing compiler
s. BCPL then led, via
B, to the popular and influential C programming language
.
Multi-paradigm programming language
Programming languages can be grouped by the number and types of paradigms supported.-Paradigm summaries:A concise reference for the programming paradigms listed in this article....
programming language
Programming language
A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....
, that was developed in the early 1960s.
Design
CPL was developed jointly between the Mathematical Laboratory at the University of CambridgeUniversity of Cambridge
The University of Cambridge is a public research university located in Cambridge, United Kingdom. It is the second-oldest university in both the United Kingdom and the English-speaking world , and the seventh-oldest globally...
and the University of London
University of London
-20th century:Shortly after 6 Burlington Gardens was vacated, the University went through a period of rapid expansion. Bedford College, Royal Holloway and the London School of Economics all joined in 1900, Regent's Park College, which had affiliated in 1841 became an official divinity school of the...
Computer Unit during the 1960s hence CPL gained the nickname "Cambridge Plus London". The collaborative effort was responsible for the "Combined" in the name of the language (previously, the name was Cambridge Programming Language). D. W. Barron
D.W. Barron
David William Barron [FBCS] is a British academic in Physics and Computer Science.- Radio Wave Propagation :Barron's work with H. Risbeth on radio wave propagation was pioneering in furthering the understanding of how radio waves were reflected at the ionospheric boundary.- Computer Science :David...
and Christopher Strachey
Christopher Strachey
Christopher Strachey was a British computer scientist. He was one of the founders of denotational semantics, and a pioneer in programming language design...
were involved (for others see paper). In 1963 (when the paper was published) it was currently being implemented on the Titan Computer
Titan (computer)
Titan was the prototype of the Atlas 2 computer developed by Ferranti and the University of Cambridge Mathematical Laboratory in Cambridge, England...
at Cambridge and the Atlas Computer
Atlas Computer (Manchester)
The Atlas Computer was a joint development between the University of Manchester, Ferranti, and Plessey. The first Atlas, installed at Manchester University and officially commissioned in 1962, was one of the world's first supercomputers, considered to be the most powerful computer in the world at...
at London.
It was heavily influenced by ALGOL 60
ALGOL 60
ALGOL 60 is a member of the ALGOL family of computer programming languages. It gave rise to many other programming languages, including BCPL, B, Pascal, Simula, C, and many others. ALGOL 58 introduced code blocks and the begin and end pairs for delimiting them...
, 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. CPL attempted to go beyond ALGOL to include industrial process control and business data processing, among other things. CPL was also 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 about 1970, but the language never gained much popularity and seems to have disappeared without trace sometime in the 1970s.
A later language based on CPL, called BCPL
BCPL
BCPL is a procedural, imperative, and structured computer programming language designed by Martin Richards of the University of Cambridge in 1966.- Design :...
(for Basic CPL, although originally Bootstrap CPL) was a much simpler language intended primarily as a systems programming language, particularly for writing compiler
Compiler
A compiler is a computer program that transforms source code written in a programming language into another computer language...
s. BCPL then led, via
B, to the popular and influential C programming language
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
.
Example
The function MAX as formulated by Peter Norvig:
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 §