Maclisp

Maclisp, also written MACLISP, is a dialect of the Lisp programming language that grew out of Project MAC at the Massachusetts Institute of Technology in the late 1960s. It was based on Lisp 1.5 and first ran on the Digital Equipment Corporation PDP-6, with Richard Greenblatt as main developer of the original codebase and Jon L. White responsible for its later maintenance. The name came into use in the early 1970s to tell it apart from other PDP-6 Lisp forks such as BBN Lisp. Maclisp replaced the association list lookup of Lisp 1.5 with a value cell for dynamic variables, added reader macros, and later gained features such as bignums, strings and a fast numeric compiler. It carried the Macsyma algebra system and the SHRDLU program and became widely used in artificial intelligence research, and it is no longer actively maintained.