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DeveloperBurstall, Popplestone
First appeared1964 (1964)
Influenced by
CPL, Lisp

COWSEL (COntrolled Working SpacE Language) is a programming language designed between 1964 and 1966 by Robin Popplestone. It was based on an RPN form of Lisp combined with some ideas from CPL.

COWSEL was initially implemented on a Ferranti Pegasus computer at the University of Leeds and on a Stantec Zebra at the Bradford Institute of Technology; later, Rod Burstall implemented it on an Elliot 4120 at the University of Edinburgh.

COWSEL was renamed POP-1 during the summer of 1966 and development continued under that name from then on.

Example code

function member
lambda x y
comment Is x a member of list y;
define      y atom then *0 end
            y hd x equal then *1 end
            y tl -> y repeat up

Note that keywords were also underlined in the original printouts. Popplestone used a Flexowriter with underscoring for syntax highlighting.

See also

  • POP-2 programming language
  • POP-11 programming language
  • Poplog programming environment


  • Technical report: EPU-R-12, U Edinburgh (Apr 1966)

External links

Edited: 2021-06-18 18:12:30