Combined Programming Language

The Combined Programming Language (CPL) was a computer programming language developed jointly between the Mathematical Laboratory at the University of Cambridge and the University of London Computer Unit during the 1960s. The collaborative effort was responsible for the "Combined" in the name of the language (previously, the name was Cambridge Programming Language). Christopher Strachey was 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 big, only moderately elegant, and complex. It was intended to be good for both scientific programming (in the way of FORTRAN and ALGOL) and also commercial programming (in the way of COBOL). In fact, it can be seen as a similar effort to PL/I in this way.

CPL proved just a bit much for the small computers and immature compiler technologies of the time. Properly working compilers were probably written by about 1970, but the language was never very popular 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 compilers. BCPL then led, via
B, to the popular and influential C programming language.

References

*D.W. Barron, J.N. Buxton, D.F. Hartley, E. Nixon, and C. Strachey. "The main features of CPL", "The Computer Journal" 6:2 (1963), pp. 134–143.