MACLISP (or Maclisp) is a dialect of the Lisp programming language. It originated at MIT's Project MAC (from which it derived its prefix) in the late 1960s and was based on Lisp 1.5. Richard Greenblatt was the main developer of the original codebase for the PDP-6; Jonl White was responsible for its later maintenance and development. The name 'Maclisp' started being used in the early 1970s to distinguish it from other forks of PDP-6 Lisp, notably BBN Lisp. Lisp is a family of computer programming languages with a long history and a distinctive fully-parenthesized syntax. ... A programming language is an artificial language that can be used to control the behavior of a machine, particularly a computer. ... The Massachusetts Institute of Technology (MIT) is a private, coeducational research university located in Cambridge, Massachusetts. ... Project MAC, later the MIT Laboratory for Computer Science (LCS), was a research laboratory at MIT. Project MAC would become famous for groundbreaking research in operating systems, artificial intelligence, and the theory of computation. ... The 1960s decade refers to the years from January 1, 1960 to December 31, 1969, inclusive. ... Richard D. Greenblatt is an American programmer. ... The PDP-6 (Programmed Data Processor-6) was a computer model developed by Digital Equipment Corporation (DEC) in 1963. ... The 1970s decade refers to the years from 1970 to 1979, also called The Seventies. ... In software engineering, a project fork or branch happens when a developer (or a group of them) takes a copy of source code from one software package and starts to independently develop a new package. ... BBN LISP was a dialect of the Lisp programming language by Bolt, Beranek and Newman Inc. ...

Maclisp ran on DEC PDP-6/10 computers, initially only on ITS, but later under all the other PDP-10 operating systems. Its original implementation was in PDP-10 assembly language. It was later implemented on Multics using PL/I. Maclisp developed considerably in its lifetime, adding major features along the way which in other language systems would typically correspond to major release numbers. The DEC logo Digital Equipment Corporation was a pioneering American company in the computer industry. ... The PDP-10 was a computer manufactured by Digital Equipment Corporation (DEC) from the late 1960s on; the name stands for Programmed Data Processor model 10. It was the machine that made time-sharing common; it looms large in hacker folklore because of its adoption in the 1970s by many... Look up its in Wiktionary, the free dictionary. ... Multics (Multiplexed Information and Computing Service) was an extraordinarily influential early time-sharing operating system. ... PL/I (Programming Language One, pronounced pee el one) is an imperative computer programming language designed for scientific, engineering, and business applications. ...

Maclisp was used to implement the Macsyma symbolic algebra program; Macsyma's development also drove a number of features in Maclisp. The SHRDLU blocks-world program was written in Maclisp, and so the language was in widespread use in the artificial intelligence research community through the early 1980s. It was also used to implement other programming languages, such as Planner and Scheme. Multics Maclisp was used to implement the first Lisp-based Emacs. MACSYMA Reference Manual, MIT, 1977 Macsyma is a computer algebra system that was originally developed from 1967 to 1982 at MIT as part of Project MAC and later marketed commercially. ... A computer algebra system (CAS) is a software program that facilitates symbolic mathematics. ... // SHRDLU was an early natural language understanding computer program, developed by Terry Winograd at MIT from 1968-1970. ... Garry Kasparov playing against Deep Blue, the first machine to win a chess game against a reigning world champion. ... This article does not cite any references or sources. ... Planner (often seen in publications as PLANNER) is a programming language designed by Carl Hewitt at MIT, and first published in 1969. ... Scheme is a multi-paradigm programming language. ... Emacs is a class of text editors, possessing an extensive set of features, that are popular with computer programmers and other technically proficient computer users. ...

Maclisp was very influential, but is no longer actively maintained. Nonetheless, it now runs on PDP-10 emulators and can be used for experimenting with early AI programs. DosBox emulates the familiar command line interface of DOS. An emulator duplicates (provide an emulation of) the functions of one system with a different system, so that the second system behaves like (and appears to be) the first system. ...

Maclisp started with a small, fixed number of data types: cons cell, atom (later called "symbol"), integer, and floating-point number. Later additions included: arrays, which were however never first-class data-types; arbitrary-precision integers (bignums); strings; and tuples. All objects (except inums) were implemented as pointers, and their data type was determined by the block of memory into which it pointed, with a special case for small numbers (inums). CONS, Connection-Oriented Network Service, is one of the two OSI stack network layer protocols, the other being CLNS (Connectionless Network Service). ...

Programs could be interpreted or compiled. Compiled behavior was the same as interpreted except that local variables were lexical by default in compiled code, and no error checking was done for inline operations such as CAR and CDR. The Ncomplr compiler (mid-1970s) introduced fast numeric support to the Lisp world, generating machine instructions for arithmetic rather than calling interpretive routines which dispatched on data type. This made Lisp arithmetic comparable in speed to Fortran for scalar operations (though Fortran array and loop implementation remained much better).

The original version was limited by the 18-bit word address of the PDP-10, and considerable effort was expended in keeping the implementation lean and simple. Multics Maclisp had a far larger address space, but was expensive to use. When the memory and processing power of the PDP-10 were exceeded, the Lisp Machine was invented: Lisp Machine Lisp is the direct descendant of Maclisp. Several other Lisp dialects were also in use, and the need to unify the community resulted in the modern Common Lisp language. The PDP-10 was a computer manufactured by Digital Equipment Corporation (DEC) from the late 1960s on; the name stands for Programmed Data Processor model 10. It was the machine that made time-sharing common; it looms large in hacker folklore because of its adoption in the 1970s by many... The original Lisp machine built by Greenblatt and Knight Lisp machines were general-purpose computers designed (usually through hardware support) to efficiently run Lisp as their main software language. ... Lisp Machine Lisp is a dialect of the Lisp programming language, a direct descendant of MacLisp, and was initially developed in the mid to late 1970s as the systems programming language for the MIT Lisp machines. ... Lisp is a family of computer programming languages with a long history and a distinctive fully-parenthesized syntax. ... Common Lisp, commonly abbreviated CL, is a dialect of the Lisp programming language, published in ANSI standard X3. ...

MACLISP was named for Project MAC, and is unrelated to Apple's Macintosh ("Mac") computer, which it predated by many years. The Lisp systems for the Macintosh, MCL and OpenMCL, have no particular similarity to Maclisp. Macintosh, also known as Mac, is a family of personal computers manufactured by Apple Computer, Inc. ... Wikipedia does not yet have an article with this exact name. ...

References

• Hackers: Heroes of the Computer Revolution

Hackers: Heroes of the Computer Revolution (ISBN 0385191952) is a book by Steven Levy about the hacker culture. ...

External links

• MacLisp manual
• The Multics Maclisp compiler