MDL programming language

MDL (the MIT Design Language) is a descendant of the Lisp programming language. Its initial purpose was to provide high level language support for the Dynamic Modeling Group at MIT's Project MAC. It was initially developed in 1971 on the  PDP-10 computer under the Incompatible Timesharing System. The initial development team consisted of Gerald Sussman and Carl Hewitt of the Artificial Intelligence Lab, and Chris Reeve, Bruce Daniels, and David Cressey of the Dynamic Modeling Group. Later, Stu Galley, also of the Dynamic Modeling Group, wrote the MDL documentation.