COWSEL is the COntrolled Working SpacE Language. Between 1964 and 1966, it was designed and implemented by Robin Popplestone, initially on a Ferranti Pegasus computer at the University of Leeds and on a Stantec Zebra at the Bradford Institute of Technology; later with Rod Burstall on an Elliot 4120 at the University of Edinburgh. It was based on a reverse Polish form of Lisp combined with some ideas from CPL. In the summer of 1966 it was renamed POP-1 and development continued under that name.

Table of contents
1 Example Code
2 Reference
3 External link

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


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

External link --The Early Development of POP