MDL

A programming language, a descendant of the language Lisp whose initial purpose was to provide high level language support for the Dynamic Modeling Group at Massachusetts Institute of Technology's (MIT) Project MAC.

Model Development Language or More Datatypes than Lisp or MIT Design Language

Wikipedia | "MDL Programming Primer" "The MDL Programming Language" "The MDL Programming Environment" | The MDL Programming Language (Source)

"The MDL programming language began existence in late 1970 (under the name Muddle) as a successor to Lisp (Moon, 1974), a candidate vehicle for the Dynamic Modeling System, and a possible base for implementation of Planner (Hewitt, 1969). The original design goals included an interactive integrated environment for programming, debugging, loading, and editing: ease in learning and use; facilities for structured, modular, shared programs; extensibility of syntax, data types and operators: data-type checking for debugging and optional data-type declarations for compiled efficiency; associative storage, coroutining, and graphics. Along the way to reaching those goals, it developed flexible input/output (including the ARPA Network), and flexible interrupt and signal handling. It now serves as a base for software prototyping, research, development, education, and implementation of the majority of programs at MIT-DMS: a library of sharable modules, a coherent user interface, special research projects, autonomous daemons, etc."

Sample of PDP-10 MDL:

 <DEFINE EXIT-TO (EXITS RMS)
         #DECL ((EXITS) EXIT (RMS) <UVECTOR [REST ROOM]>)
         <MAPF <>
               <FUNCTION (E)
                  #DECL ((E) <OR DIRECTION ROOM CEXIT NEXIT DOOR>)
                  <COND (<TYPE? .E DIRECTION>)
                        (<AND <TYPE? .E ROOM> <MEMQ .E .RMS>>
                         <MAPLEAVE T>)
                        (<AND <TYPE? .E CEXIT> <MEMQ <2 .E> .RMS>>
                         <MAPLEAVE T>)
                        (<AND <TYPE? .E DOOR>
                              <OR <MEMQ <DROOM1 .E> .RMS>
                                  <MEMQ <DROOM2 .E> .RMS>>>
                         <MAPLEAVE T>)>>
               .EXITS>>

Tags: language   gamedev   dynamic   functional  

Last modified 12 December 2025