PLAnner-like System Modelled on ActORs. Carl Hewitt, 1975. The first actOR language. ORiginally called Planner-73, and implemented in MacLisp. Lisp-like syntax, but with several kinds of parentheses and brackets. ["A PLASMA Primer", B. Smith et al, AI Lab WORking Paper 92, MIT Oct 1975]. ["Viewing Control Structures as Patterns of Passing Messages", C. Hewitt, AI Lab Memo 410, MIT 1976].