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

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

=See also=

=Reference=

=External links=