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Encyclopedia > Lisp (programming language)
Lisp
Paradigm: multi-paradigm: functional, procedural, reflective
Appeared in: 1958
Designed by: John McCarthy
Developer: Steve Russell, Timothy P. Hart, and Mike Levin
Typing discipline: dynamic, strong
Dialects: Common Lisp, Scheme, Emacs Lisp
Influenced: Logo, Smalltalk, Ruby, Dylan, Mathematica

Lisp is a family of computer programming languages with a long history and a distinctive fully-parenthesized syntax. Originally specified in 1958, Lisp is the second-oldest high-level programming language in widespread use today; only Fortran is older. Like Fortran, Lisp has changed a great deal since its early days, and a number of dialects have existed over its history. Today, the most widely-known general-purpose Lisp dialects are Common Lisp and Scheme. For the programming language, see Lisp (programming language). ... A programming paradigm is a paradigmatic style of programming (compare with a methodology, which is a paradigmatic style of doing software engineering). ... This does not cite any references or sources. ... Functional programming is a programming paradigm that conceives computation as the evaluation of mathematical functions and avoids state and mutable data. ... This does not adequately cite its references or sources. ... In computer science, reflection is the process by which a computer program of the appropriate type can be modified in the process of being executed, in a manner that depends on abstract features of its code and its runtime behavior. ... Year 1958 (MCMLVIII) was a common year starting on Wednesday (link will display full calendar) of the Gregorian calendar. ... John McCarthy (born September 4, 1927, in Boston, Massachusetts, sometimes known affectionately as Uncle John McCarthy), is a prominent computer scientist who received the Turing Award in 1971 for his major contributions to the field of Artificial Intelligence. ... For other uses, see Software developer (disambiguation). ... Steve Russel created the first videogame, Spacewar at the Tech Model Railroad Club at the MIT. Categories: Substubs ... In computer science, a type system defines how a programming language classifies values and expressions into types, how it can manipulate those types and how they interact. ... In computer science, a type system defines how a programming language classifies values and expressions into types, how it can manipulate those types and how they interact. ... In computer science and computer programming, the term strong typing is used to describe those situations where programming languages specify one or more restrictions on how operations involving values having different datatypes can be intermixed. ... A dialect of a programming language is a (relatively small) variation or extension of the language that does not change its intrinsic nature. ... Common Lisp, commonly abbreviated CL, is a dialect of the Lisp programming language, published in ANSI standard X3. ... Scheme is a multi-paradigm programming language. ... Emacs Lisp is a dialect of the Lisp programming language used by the GNU Emacs and XEmacs text editors (which we will collectively refer to as Emacs in this article. ... Logo turtle graphic The Logo programming language is a functional programming language. ... For other uses, see Small talk. ... Ruby is a reflective, dynamic, object-oriented programming language. ... The Dylan programming language (pronounced , like the name) is functional, object-oriented, reflective and dynamic. ... For other uses, see Mathematica (disambiguation). ... This article is about the machine. ... Computer programming (often shortened to programming or coding) is the process of writing, testing, and maintaining the source code of computer programs. ... Year 1958 (MCMLVIII) was a common year starting on Wednesday (link will display full calendar) of the Gregorian calendar. ... A high-level programming language is a programming language that, in comparison to low-level programming languages, may be more abstract, easier to use, or more portable across platforms. ... Fortran (previously FORTRAN[1]) is a general-purpose[2], procedural,[3] imperative programming language that is especially suited to numeric computation and scientific computing. ... A dialect of a programming language is a (relatively small) variation or extension of the language that does not change its intrinsic nature. ... Common Lisp, commonly abbreviated CL, is a dialect of the Lisp programming language, published in ANSI standard X3. ... Scheme is a multi-paradigm programming language. ...


Lisp was originally created as a practical mathematical notation for computer programs, based on Alonzo Church's lambda calculus. It quickly became the favored programming language for artificial intelligence research. As one of the earliest programming languages, Lisp pioneered many ideas in computer science, including tree data structures, automatic storage management, dynamic typing, object-oriented programming, and the self-hosting compiler. ‹ The template below (Expand) is being considered for deletion. ... The lambda calculus is a formal system designed to investigate function definition, function application, and recursion. ... Garry Kasparov playing against Deep Blue, the first machine to win a chess game against a reigning world champion. ... Computer science, or computing science, is the study of the theoretical foundations of information and computation and their implementation and application in computer systems. ... In computer science, a tree is a widely-used computer data structure that emulates a tree structure with a set of linked nodes. ... In computer science, garbage collection (GC) is a form of automatic memory management. ... In computer science, a datatype or data type (often simply a type) is a name or label for a set of values and some operations which one can perform on that set of values. ... Object-oriented programming (OOP) is a programming paradigm that uses objects and their interactions to design applications and computer programs. ... Self-hosting refers to the use of a computer program as part of the toolchain or operating system that produces new versions of that same program—for example, a compiler that can compile its own source code. ... A diagram of the operation of a typical multi-language, multi-target compiler. ...


The name Lisp derives from "List Processor". Linked lists are one of Lisp languages' major data structures, and Lisp source code is itself made up of lists. As a result, Lisp programs can manipulate source code as a data structure, giving rise to the macro systems that allow programmers to create new syntax or even new "little languages" embedded in Lisp. In computer science, a linked list is one of the fundamental data structures, and can be used to implement other data structures. ... A binary tree, a simple type of branching linked data structure. ... Source code (commonly just source or code) is any series of statements written in some human-readable computer programming language. ... A macro in computer science is an abstraction, that defines how a certain input pattern is replaced by an output pattern according to a defined set of rules. ... A domain-specific programming language (domain-specific language, DSL) is a programming language designed to be useful for a specific set of tasks. ...


The interchangeability of code and data also gives Lisp its instantly recognizable syntax. All program code is written as s-expressions, or parenthesized lists. A function call or syntactic form is written as a list with the function or operator's name first, and the arguments following; for instance, a function f that takes three arguments might be called using (f x y z). An S-expression (S stands for symbolic) is a convention for representing data or an expression in a computer program in a text form. ...

Contents

The invention of Lisp

Lisp was invented by John McCarthy in 1958 while he was at MIT. McCarthy published its design in a paper in Communications of the ACM in 1960, entitled "Recursive Functions of Symbolic Expressions and Their Computation by Machine, Part I"[1] (Part II was never published). He showed that with a few simple operators and a notation for functions, one can build a Turing-complete language for algorithms. John McCarthy (born September 4, 1927, in Boston, Massachusetts, sometimes known affectionately as Uncle John McCarthy), is a prominent computer scientist who received the Turing Award in 1971 for his major contributions to the field of Artificial Intelligence. ... Year 1958 (MCMLVIII) was a common year starting on Wednesday (link will display full calendar) of the Gregorian calendar. ... The Massachusetts Institute of Technology (MIT) is a private, coeducational research university located in Cambridge, Massachusetts. ... Communications of the ACM (CACM) is the flagship monthly magazine of the Association for Computing Machinery. ... Year 1960 (MCMLX) was a leap year starting on Friday (link will display full calendar) of the Gregorian calendar. ... In computability theory a programming language or any other logical system is called Turing-complete if it has a computational power equivalent to a universal Turing machine. ...


Lisp was first implemented by Steve Russell on an IBM 704 computer. Russell had read McCarthy's paper, and realized (to McCarthy's surprise) that the eval function could be implemented as a Lisp interpreter. Steve Russel created the first videogame, Spacewar at the Tech Model Railroad Club at the MIT. Categories: Substubs ... The IBM 704, the first mass-produced computer with floating point arithmetic hardware, was introduced by IBM in April, 1956. ...


The first complete Lisp compiler, written in Lisp, was implemented in 1962 by Tim Hart and Mike Levin at MIT.[2] This compiler introduced the Lisp model of incremental compilation, in which compiled and interpreted functions can intermix freely. The language used in Hart and Levin's memo is much closer to modern Lisp style than McCarthy's earlier code. Year 1962 (MCMLXII) was a common year starting on Monday (the link is to a full 1962 calendar) of the Gregorian calendar. ...


Curiosities of the early history

Information Processing Language was the first AI language, from 1955 or 1956, and already included many of the concepts, such as list-processing and recursion, which came to be used in Lisp. Information Processing Language (IPL) is a programming language developed by Allen Newell, Cliff Shaw, and Herbert Simon at RAND Corporation and the Carnegie Institute of Technology from about 1956. ...


McCarthy's original notation used bracketed "M-expressions" that would be translated into S-expressions. As an example, the M-expression car[cons[A,B]] is equivalent to the S-expression (car (cons A B)). Once Lisp was implemented, programmers rapidly chose to use S-expressions, and M-expressions were abandoned. M-expressions surfaced again with short-lived attempts of MLISP[3] by Horace Enea and CGOL by Vaughan Pratt. M-Expressions are so-called meta-expressions which were intended to be used in Lisp. ... Vaughan Pratt is Professor Emeritus of Computer Science at Stanford University. ...


Two assembly language macros for the IBM 704 became the primitive operations for decomposing lists: car (Contents of Address Register) and cdr (Contents of Decrement Register). Lisp dialects still use car and cdr (pronounced: [kɑr] and ['kʊdər]) for the operations that return the first item in a list and the rest of the list respectively. A macro in computer science is an abstraction, that defines how a certain input pattern is replaced by an output pattern according to a defined set of rules. ... The IBM 704, the first mass-produced computer with floating point arithmetic hardware, was introduced by IBM in April, 1956. ... Introduced in the Lisp programming language, car (IPA [kar], just like the English word car) and cdr (IPA [kÊŒ dÉ™r] or [ku dÉ™r]) are primitive operations upon linked lists composed of cons cells. ... Introduced in the Lisp programming language, car (IPA [kar], just like the English word car) and cdr (IPA [kÊŒ dÉ™r] or [ku dÉ™r]) are primitive operations upon linked lists composed of cons cells. ... The symbols of the International Phonetic Alphabet can be used to show pronounciation in English. ...


Genealogy and variants

Over its almost fifty-year history, Lisp has spawned many variations on the core theme of an S-expression language. Moreover, each given dialect may have several implementations – for instance, there are more than a dozen implementations of Common Lisp. Common Lisp, commonly abbreviated CL, is a dialect of the Lisp programming language, published in ANSI standard X3. ...


Differences between dialects may be quite visible – for instance, Common Lisp and Scheme use different keywords to define functions. Within a dialect that is standardized, however, conforming implementations support the same core language, but with different extensions and libraries.


Historically significant dialects

  • LISP 1.5 [2] – First widely distributed version, developed by McCarthy and others at MIT. So named because it contained several improvements on the original "LISP 1" interpreter, but was not a major restructuring as the planned LISP 2 would be. (LISP 2 used an M-expression-based syntax and would not be widely used.)
  • Stanford LISP 1.6 [3] – This was a successor to LISP 1.5 developed at the Stanford AI Lab, and widely distributed to PDP-10 systems running the TOPS-10 operating system. It was obsoleted by Maclisp and InterLisp.
  • MACLISP [4] – developed for MIT's Project MAC (no relation to Apple's Macintosh, nor to McCarthy), direct descendant of LISP 1.5. It ran on the PDP-10 and Multics systems.
  • InterLisp [5] – developed at BBN for PDP-10 systems running the Tenex operating system, later adopted as a "West coast" Lisp for the Xerox Lisp machines. A small version called "InterLISP 65" was published for Atari's 6502-based computer line. For quite some time MacLisp and InterLisp were strong competitors.
  • Franz Lisp – originally a Berkeley project; later developed by Franz Inc. The name is a humorous deformation of 'Franz Liszt'.
  • ZetaLisp – used on the Lisp machines, direct descendant of MacLisp.
  • EuLisp – attempt to develop a new efficient and cleaned-up Lisp.
  • ISLisp – attempt to develop a new efficient and cleaned-up Lisp. Standardized.
  • IEEE Scheme – IEEE standard, 1178-1990 (R1995)
  • ANSI Common Lisp – mostly, a cleaned up subset of ZetaLisp incorporating CLOS.

M-Expressions are so-called meta-expressions which were intended to be used in Lisp. ... The Stanford Artificial Intelligence Laboratory (commonly called the Stanford AI Lab, or SAIL), was one of the leading centres for artificial intelligence research from the 1960s through the 1980s. ... 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 TOPS-10 System was a computer operating system from Digital Equipment Corporation (DEC) for the PDP-10 released in 1964 and later on for the DEC-System10. ... MACLISP (or Maclisp) is a dialect of the Lisp programming language. ... Interlisp (also seen with a variety of capitalizations) was a version of the Lisp programming language originally developed in 1967 at Bolt, Beranek and Newman in Cambridge, Massachusetts. ... MACLISP (or Maclisp) is a dialect of the Lisp programming language. ... 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 first Macintosh computer, introduced in 1984, upgraded to a 512K Fat Mac. The Macintosh or Mac, is a line of personal computers designed, developed, manufactured, and marketed by Apple Computer. ... John McCarthy (born September 4, 1927, in Boston, Massachusetts, sometimes known affectionately as Uncle John McCarthy), is a prominent computer scientist who received the Turing Award in 1971 for his major contributions to the field of Artificial Intelligence. ... 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... Multics (Multiplexed Information and Computing Service) was an extraordinarily influential early time-sharing operating system. ... Interlisp (also seen with a variety of capitalizations) was a version of the Lisp programming language originally developed in 1967 at Bolt, Beranek and Newman in Cambridge, Massachusetts. ... BBN might refer to: Bolt, Beranek and Newman, (now known as BBN Technologies), a technology company in Cambridge, Massachusetts, best known for its work on packet switching technology Bible Broadcasting Network, a global Christian radio network headquartered in Charlotte, NC Big Bang nucleosynthesis Big Brother Nigeria, a reality show which... 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 TOPS-20 operating system by DEC was the second proprietary OS for the PDP-10. ... This article is about a corporate game company. ... The MOS Technology 6502 is an 8-bit microprocessor that was designed by Chuck Peddle for MOS Technology in 1975. ... Franz Lisp, written at UC Berkeley by the students of Professor Richard J. Fateman, was a Lisp system based larged on Maclisp, but written specifically to be a host for running Macsyma on a Digital Equipment Corp (DEC) VAX. It appeared on the scene at the end of 1978 shortly... Sather tower (the Campanile) looking out over the San Francisco Bay and Mount Tamalpais. ... Franz Inc. ... “Liszt” redirects here. ... ZetaLisp was the name Symbolics gave to their dialect of Lisp on their Lisp Machine models, to distinguish it from the MIT version. ... 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. ... MACLISP (or Maclisp) is a dialect of the Lisp programming language. ... Please wikify (format) this article as suggested in the Guide to layout and the Manual of Style. ... From ISLISP.info: The ISLISP programming language is a member of the Lisp family of programming languages. ... Scheme is a multi-paradigm programming language. ... The American National Standards Institute or ANSI (pronounced an-see) is a nonprofit organization that oversees the development of standards for products, services, processes and systems in the United States. ... Common Lisp, commonly abbreviated CL, is a dialect of the Lisp programming language, published in ANSI standard X3. ... ZetaLisp was the name Symbolics gave to their dialect of Lisp on their Lisp Machine models, to distinguish it from the MIT version. ... The Common Lisp Object System (CLOS) is the facility for object-oriented programming which is part of Common Lisp (CL). ...

Lisp and AI

Since its inception, Lisp was closely connected with the artificial intelligence research community, especially on PDP-10[4] systems. Lisp was used as the implementation of the programming language Micro Planner that was the foundation for the famous AI system SHRDLU. In the 1970s, as AI research spawned commercial offshoots, the performance of existing Lisp systems became a growing issue. Garry Kasparov playing against Deep Blue, the first machine to win a chess game against a reigning world champion. ... 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... Planner (often seen in publications as PLANNER) is a programming language designed by Carl Hewitt at MIT, and first published in 1969. ... // SHRDLU was an early natural language understanding computer program, developed by Terry Winograd at MIT from 1968-1970. ... The 1970s decade refers to the years from 1970 to 1979, also called The Seventies. ...


Lisp was a difficult system to implement with the compiler techniques and stock hardware of the 1970s. Garbage collection routines, developed by then-MIT graduate student Daniel Edwards, made it practical to run Lisp on general-purpose computing systems, but efficiency was still a problem. This led to the creation of Lisp machines: dedicated hardware for running Lisp environments and programs. Advances in both computer hardware and compiler technology soon made Lisp machines obsolete, to the detriment of the Lisp market. In computer science, garbage collection (GC) is a form of automatic memory management. ... Mapúa Institute of Technology (MIT, MapúaTech or simply Mapúa) is a private, non-sectarian, Filipino tertiary institute located in Intramuros, Manila. ... 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. ...


During the 1980s and 1990s, a great effort was made to unify the numerous Lisp dialects (most notably, InterLisp, Maclisp, ZetaLisp, and Franz Lisp) into a single language. The new language, Common Lisp, was essentially a compatible subset of the dialects it replaced. In 1994, ANSI published the Common Lisp standard, "ANSI X3.226-1994 Information Technology Programming Language Common Lisp." At that time the world market for Lisp was much smaller than it is today. The 1980s refers to the years from 1980 to 1989. ... For the band, see 1990s (band). ... Interlisp (also seen with a variety of capitalizations) was a version of the Lisp programming language originally developed in 1967 at Bolt, Beranek and Newman in Cambridge, Massachusetts. ... MACLISP (or Maclisp) is a dialect of the Lisp programming language. ... ZetaLisp was the name Symbolics gave to their dialect of Lisp on their Lisp Machine models, to distinguish it from the MIT version. ... Franz Lisp, written at UC Berkeley by the students of Professor Richard J. Fateman, was a Lisp system based larged on Maclisp, but written specifically to be a host for running Macsyma on a Digital Equipment Corp (DEC) VAX. It appeared on the scene at the end of 1978 shortly... Common Lisp, commonly abbreviated CL, is a dialect of the Lisp programming language, published in ANSI standard X3. ... Year 1994 (MCMXCIV) was a common year starting on Saturday (link will display full 1994 Gregorian calendar). ... The American National Standards Institute (ANSI) is a private, non-profit standards organization that produces industrial standards in the United States. ...


Lisp today

Having declined somewhat in the 1990s, Lisp has experienced a regrowth of interest since 2000. Most new activity is focused around open source implementations of Common Lisp, and includes the development of new portable libraries and applications. Year 2000 (MM) was a leap year starting on Saturday (link will display full 2000 Gregorian calendar). ... Open source refers to projects that are open to the public and which draw on other projects that are freely available to the general public. ... Common Lisp, commonly abbreviated CL, is a dialect of the Lisp programming language, published in ANSI standard X3. ...


Many new Lisp programmers were inspired by writers such as Paul Graham and Eric S. Raymond to pursue a language others consider antiquated. New Lispers often describe the language as an eye-opening experience and claim to be substantially more productive than in other languages. [5] Graham is developing a new Lisp dialect called Arc. Paul Graham For Paul Graham the photographer, see Paul Graham (photographer). ... Eric S. Raymond (FISL 6. ... Paul Graham For Paul Graham the photographer, see Paul Graham (photographer). ... Arc is a dialect of Lisp, currently developed by Paul Graham. ...


Peter Seibel's Practical Common Lisp, a tutorial for new Lisp programmers published in 2004, was briefly Amazon.com's second most popular programming book. Practical Common Lisp (ISBN 1590592395) is an introductory book on Common Lisp by Peter Seibel which in the third chapter implements a testing framework, then discusses most of Common Lisps language features and finally in the last chapters implements a spam filter and a SHOUTcast server. ...


Major modern dialects

The two major dialects of Lisp used for general-purpose programming today are Common Lisp and Scheme. These languages represent significantly different design choices. Common Lisp, commonly abbreviated CL, is a dialect of the Lisp programming language, published in ANSI standard X3. ... Scheme is a multi-paradigm programming language. ...


Common Lisp, descended mainly from MacLisp, Interlisp, and Lisp Machine Lisp, is an expanded superset of earlier Lisp dialects, with a large language standard including many built-in data types and syntactic forms, as well as an object system. Scheme is a more minimalist design, with a much smaller set of standard features but with certain implementation features (such as tail-call optimization and full continuations) not necessarily found in Common Lisp. Common Lisp also borrowed certain features from Scheme such as lexical scoping and lexical closures. MACLISP (or Maclisp) is a dialect of the Lisp programming language. ... Interlisp (also seen with a variety of capitalizations) was a version of the Lisp programming language originally developed in 1967 at Bolt, Beranek and Newman in Cambridge, Massachusetts. ... 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. ... In computer science, tail recursion (or tail-end recursion) is a special case of recursion in which the last operation of the function is a recursive call. ... In computing, a continuation is a representation of some of the execution state of a program (often the call stack and the current Instruction pointer) at a certain point. ... In computer programming, scope is an enclosing context where values and expressions are associated. ... In programming languages, a closure is an abstraction representing a function, plus the lexical environment (see static scoping) in which the function was created, and its application to arguments. ...


In addition, Lisp dialects are used as scripting languages in a number of applications, with the most well-known being Emacs Lisp in the Emacs editor and Autolisp in AutoCAD. Scripting languages (commonly called scripting programming languages or script languages) are computer programming languages that are typically interpreted and can be typed directly from a keyboard. ... Emacs Lisp is a dialect of the Lisp programming language used by the GNU Emacs and XEmacs text editors (which we will collectively refer to as Emacs in this article. ... 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. ... AutoLISP is a programming language, a dialect of Lisp included with the CAD program AutoCAD to allow the user to add functionality to the software. ... AutoCAD is a suite of CAD software products for 2- and 3-dimensional design and drafting, developed and sold by Autodesk, Inc. ...


Language innovations

Lisp was the first homoiconic programming language: the primary representation of program code is the same type of list structure that is also used for the main data structures. As a result, Lisp functions can be manipulated, altered or even created within a Lisp program without extensive parsing or manipulation of binary machine code. This is generally considered one of the primary advantages of the language with regards to its expressiveness, and makes the language amenable to metacircular evaluation. In computer programming, homoiconicity is a property of some programming languages, in which the primary representation of programs is also a data structure in a primitive type of the language itself, from homo meaning the same and icon meaning representation. ... A meta-circular evaluator is a special case of a self-interpreter in which the existing facilities of the parent interpreter are directly applied to the source code being interpreted, without any need for additional parsing. ...


The now-ubiquitous if-then-else structure, now taken for granted as an essential element of any programming language, was invented by McCarthy for use in Lisp, where it saw its first appearance in a more general form (the cond structure). It was inherited by Algol, which popularized it.


Lisp deeply influenced Alan Kay, the leader of the research on Smalltalk, and then in turn Lisp was influenced by Smalltalk, by adopting object-oriented programming features (classes, instances, etc.) in the late 1970s. Alan Curtis Kay (born May 17, 1940) is an American computer scientist, known for his early pioneering work on object-oriented programming and windowing graphical user interface design. ... For other uses, see Small talk. ...


Largely because of its resource requirements with respect to early computing hardware (including early microprocessors), Lisp did not become as popular outside of the AI community as Fortran and the ALGOL-descended C language. Newer languages such as Java and Python have incorporated some limited versions of some of the features of Lisp, but are necessarily unable to bring the coherence and synergy of the full concepts found in Lisp. Because of its suitability to ill-defined, complex, and dynamic applications, Lisp is currently enjoying some resurgence of popular interest. // This disambiguation page covers alternative uses of the terms Ai, AI, and A.I. Ai (as a word, proper noun and set of initials) can refer to many things. ... Fortran (previously FORTRAN[1]) is a general-purpose[2], procedural,[3] imperative programming language that is especially suited to numeric computation and scientific computing. ... It has been suggested that ALGOL object code be merged into this article or section. ... C is a general-purpose, block structured, procedural, imperative computer programming language developed in 1972 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system. ... “Java language” redirects here. ... Python is a high-level programming language first released by Guido van Rossum in 1991. ...


See also "The evolution of Lisp"[6], a paper written by Guy L. Steele, Jr. and Richard P. Gabriel. Guy Lewis Steele, Jr. ... Richard P. Gabriel (b. ...


Syntax and semantics

Note: This article's examples are written in Common Lisp (though most are also valid Scheme).

Lisp is an expression-oriented language. Unlike most other languages, no distinction is made between "expressions" and "statements"; all code and data are written as expressions. When an expression is evaluated, it produces a value (or list of values), which then can be embedded into other expressions. Common Lisp, commonly abbreviated CL, is a dialect of the Lisp programming language, published in ANSI standard X3. ... Scheme is a multi-paradigm programming language. ... An expression in a programming language is a combination of values and functions or procedures, interpreted according to the particular rules of precedence and of association for a particular programming language, which computes and then returns another value. ... A statement is the minimal unit of structuring in imperative programming languages. ...


McCarthy's 1958 paper introduced two types of syntax: S-expressions (Symbolic Expressions, also called "sexps"), which mirror the internal representation of code and data; and M-expressions (Meta Expressions), which express functions of S-expressions. M-expressions never found favour, and almost all Lisps today use S-expressions to manipulate both code and data. An S-expression (S stands for symbolic) is a convention for representing data or an expression in a computer program in a text form. ... M-Expressions are so-called meta-expressions which were intended to be used in Lisp. ...


The use of parentheses is Lisp's most immediately obvious difference from other programming language families. As a result, students have long given Lisp nicknames such as "Lots of Irritating Superfluous Parentheses"[2]. However, the S-expression syntax is also responsible for much of Lisp's power; the syntax is extremely regular, which facilitates manipulation by computer. However, the syntax of Lisp is not limited to traditional parentheses notation. It can be extended to include alternative notations. XMLisp, for instance, is a Common Lisp extension that employs the metaobject-protocol to integrate S-expressions with the Extensible Markup Language (XML). Metaobject is any entity that exhibits some aspects of objects, like type, interface, class, methods, attributes, variables, functions, control structures and many more. ... The Extensible Markup Language (XML) is a general-purpose markup language. ...


The reliance on expressions gives the language great flexibility. Because Lisp functions are themselves written as lists, they can be processed exactly like data. This allows easy writing of programs which manipulate other programs (metaprogramming). Many Lisp dialects exploit this feature using macro systems, which enables extension of the language almost without limit. In computer science, a subroutine (function, procedure, or subprogram) is a sequence of code which performs a specific task, as part of a larger program, and is grouped as one, or more, statement blocks; such code is sometimes collected into software libraries. ... Metaprogramming is the writing of computer programs that write or manipulate other programs (or themselves) as their data or that do part of the work during compile time that is otherwise done at run time. ... A macro in computer science is an abstraction, that defines how a certain input pattern is replaced by an output pattern according to a defined set of rules. ...


A Lisp list is written with its elements separated by whitespace, and surrounded by parentheses. For example, (1 2 foo) is a list whose elements are three atoms, the values 1, 2, and foo. These values are implicitly typed: they are respectively two integers and a Lisp-specific data type called a "symbol", and do not have to be declared as such. A metasyntactic variable is a placeholder name, or a kind of alias term, commonly used to denote the subject matter under discussion, or a random member of a class of things under discussion. ...


The empty list () is also represented as the special atom nil. This is the only entity in Lisp which is both an atom and a list.


Expressions are written as lists, using prefix notation. The first element in the list is the name of a form, i.e., a function, operator, macro, or "special operator" (see below.) The remainder of the list are the arguments. For example, the function list returns its arguments as a list, so the expression Polish notation, also known as prefix notation was created by Jan Łukasiewicz. ...

 (list '1 '2 'foo) 

evaluates to the list (1 2 foo). The "quote" before the arguments in the preceding example is a "special operator" which prevents the quoted arguments being evaluated (not strictly necessary for the numbers, since 1 evaluates to 1, etc). Any unquoted expressions are recursively evaluated before the enclosing expression is evaluated. For example,

 (list 1 2 (list 3 4)) 

evaluates to the list (1 2 (3 4)). Note that the third argument is a list; lists can be nested.


Arithmetic operators are treated similarly. The expression

 (+ 1 2 3 4) 

evaluates to 10. The equivalent under infix notation would be "1 + 2 + 3 + 4". Arithmetic operators in Lisp are variadic (or n-ary), able to take any number of arguments. Infix notation is the common arithmetic and logical formula notation, in which operators are written infix-style between the operands they act on (e. ... In computer programming, a variadic function is a function of variable arity; that is, one which can take different numbers of arguments. ... In logic, mathematics, and computer science, the arity (synonyms include type, adicity, and rank) of a function or operation is the number of arguments or operands that the function takes. ...


"Special operators" (sometimes called "special forms" by older users) provide Lisp's control structure. For example, the special operator if takes three arguments. If the first argument is non-nil, it evaluates to the second argument; otherwise, it evaluates to the third argument. Thus, the expression

 (if nil (list 1 2 "foo") (list 3 4 "bar")) 

evaluates to (3 4 "bar"). Of course, this would be more useful if a non-trivial expression had been substituted in place of nil.


Lambda expressions

Another special operator, lambda, is used to bind variables to values which are then evaluated within an expression. This operator is also used to create functions: the arguments to lambda are a list of arguments, and the expression or expressions to which the function evaluates (the returned value is the value of the last expression that is evaluated). The expression

 (lambda (arg) (+ arg 1)) 

is an expression which, when applied, takes one argument, bound to arg and returns the number one greater than that argument. Lambda expressions are treated no differently from named functions; they are invoked the same way. Therefore, the expression

 ((lambda (arg) (+ arg 1)) 5) 

evaluates to 6.


Atoms

In the original LISP there were two fundamental data types: atoms and lists. A list was a finite ordered sequence of elements, where each element is in itself either an atom or a list, and an atom was a number or a symbol. A symbol was essentially a unique named item, written as an Alphanumeric string in source code, and used either as a variable name or as a data item in symbolic processing. For example, the list (FOO (BAR 1) 2) contains three elements: the symbol FOO, the list (BAR 1), and the number 2. A data type is a constraint placed upon the interpretation of data in a type system in computer programming. ... For other uses, see Number (disambiguation). ... Generally speaking, the term alphanumeric refers to anything that consists of only letters and numbers. ... Source code (commonly just source or code) is any series of statements written in some human-readable computer programming language. ...


The essential difference between atoms and lists was that atoms were immutable and unique. Two atoms that appeared in different places in source code but were written in the exact same way represented the same object, whereas each list was a separate object that could be altered independently of other lists and could be distinguished from other lists by comparison operators.


As more data types were introduced in later Lisp dialects, and programming styles evolved, the concept of an atom lost importance. Many dialects still retained the predicate atom for legacy compatibility, defining it as true for anything that is not a cons cell (ie. a list or a partial list). Programming style refers to a set of rules or guidelines used when writing the source code for a computer program. ... CONS, Connection-Oriented Network Service, is one of the two OSI stack network layer protocols, the other being CLNS (Connectionless Network Service). ...


Conses and lists

Main article: Cons

A Lisp list is a singly-linked list. Each cell of this list is called a cons (in Scheme, a pair), and is composed of two pointers, called the car and cdr. These are equivalent to the data and next fields discussed in the article linked list, respectively. CONS, Connection-Oriented Network Service, is one of the two OSI stack network layer protocols, the other being CLNS (Connectionless Network Service). ... In computer science, a linked list is one of the fundamental data structures used in computer programming. ... It has been suggested that Software pointer be merged into this article or section. ... In computer science, a linked list is one of the fundamental data structures, and can be used to implement other data structures. ...


Of the many data structures that can be built out of cons cells, one of the most basic is called a proper list. A proper list is either the special nil (empty list) symbol, or a cons in which the car points to a datum (which may be another cons structure, such as a list), and the cdr points to another proper list.


If a given cons is taken to be the head of a linked list, then its car points to the first element of the list, and its cdr points to the rest of the list. For this reason, the car and cdr functions are also called first and rest when referring to conses which are part of a linked list (rather than, say, a tree).


Thus, a Lisp list is not an atomic object, as an instance of a container class in C++ or Java would be. A list is nothing more than an aggregate of linked conses. A variable which refers to a given list is simply a pointer to the first cons in the list. Traversal of a list can be done by "cdring down" the list; that is, taking successive cdrs to visit each cons of the list; or by using any of a number of higher-order functions to map a function over a list. In mathematics and computer science, higher-order functions are functions which can take other functions as arguments, and may also return functions as results. ...


Because conses and lists are so universal in Lisp systems, it is a common misconception that they are Lisp's only data structures. In fact, all but the most simplistic Lisps have other data structures – such as vectors (arrays), hash tables, structures, and so forth. This article does not cite any references or sources. ...


S-expressions represent lists

Parenthesized S-expressions represent linked list structure. There are several ways to represent the same list as an S-expression. A cons can be written in dotted-pair notation as (a . b), where a is the car and b the cdr. A longer proper list might be written (a . (b . (c . (d . nil)))) in dotted-pair notation. This is conventionally abbreviated as (a b c d) in list notation. An improper list may be written in a combination of the two – as (a b c . d) for the list of three conses whose last cdr is d (i.e., the list (a . (b . (c . d))) in fully-specified form).


List-processing procedures

Lisp provides many built-in procedures for accessing and controlling lists. Lists can be created directly with the list procedure, which takes any number of arguments, and returns the list of these arguments.

 (list 1 2 'a 3) ;Output: (1 2 a 3) 
 (list 1 '(2 3) 4) ;Output: (1 (2 3) 4) 

Because of the way that lists are constructed from cons pairs, the cons procedure can be used to add an element to the front of a list. Note that the cons procedure is asymmetric in how it handles list arguments, because of how lists are constructed. A cons pair or cell is a data structure from the Lisp programming language, used to couple two values together. ... CONS, Connection-Oriented Network Service, is one of the two OSI stack network layer protocols, the other being CLNS (Connectionless Network Service). ...

 (cons 1 '(2 3)) ;Output: (1 2 3) 
 (cons '(1 2) '(3 4)) ;Output: ((1 2) 3 4) 

The append procedure appends two (or more) lists to one another. Because Lisp lists are linked lists, appending two lists has asymptotic time complexity O(n). In computer programming, append is the name of a procedure for concatenating (linked) lists or arrays in some high-level programming languages. ... For other uses, see Big O. In computational complexity theory, big O notation is often used to describe how the size of the input data affects an algorithms usage of computational resources (usually running time or memory). ...

 (append '(1 2) '(3 4)) ;Output: (1 2 3 4) 
 (append '(1 2 3) '() '(a) '(5 6)) ;Output: (1 2 3 a 5 6) 

Shared structure

Lisp lists, being simple linked lists, can share structure with one another. That is to say, two lists can have the same tail, or final sequence of conses. For instance, after the execution of the following Common Lisp code:

 (setq foo (list 'a 'b 'c)) (setq bar (cons 'x (cdr foo))) 

the lists foo and bar are (a b c) and (x b c) respectively. However, the tail (b c) is the same structure in both lists. It is not a copy; the cons cells pointing to b and c are in the same memory locations for both lists.


Sharing structure rather than copying can give a dramatic performance improvement. However, this technique can interact in undesired ways with functions that alter lists passed to them as arguments. Altering one list, such as by replacing the c with a goose, will affect the other:

 (setf (third foo) 'goose) 

This changes foo to (a b goose), but thereby also changes bar to (x b goose) – a possibly unexpected result. This can be a source of bugs, and functions which alter their arguments are documented as destructive for this very reason.


Aficionados of functional programming avoid destructive functions. In the Scheme dialect, which favors the functional style, the names of destructive functions are marked with a cautionary exclamation point, or "bang" — such as set-car! (read set car bang), which replaces the car of a cons. In the Common Lisp dialect, destructive functions are commonplace; the equivalent of set-car! is named rplaca for "replace car." This function is rarely seen however as Common Lisp includes a special facility, setf, to make it easier to define and use destructive functions. A frequent style in Common Lisp is to write code functionally (without destructive calls) when prototyping, then to add destructive calls as an optimization where it is safe to do so. Functional programming is a programming paradigm that conceives computation as the evaluation of mathematical functions and avoids state and mutable data. ...


Self-evaluating forms and quoting

Lisp evaluates expressions which are entered by the user. Symbols and lists evaluate to some other (usually, simpler) expression – for instance, a symbol evaluates to the value of the variable it names; (+ 2 3) evaluates to 5. However, most other forms evaluate to themselves: if you enter 5 into Lisp, it returns 5.


Any expression can also be marked to prevent it from being evaluated (as is necessary for symbols and lists). This is the role of the quote special operator, or its abbreviation ' (a single quotation mark). For instance, usually if you enter the symbol foo you will get back the value of the corresponding variable (or an error, if there is no such variable). If you wish to refer to the literal symbol, you enter (quote foo) or, usually, 'foo.


Both Common Lisp and Scheme also support the backquote operator (often called quasiquote by Schemers), entered with the ` character. This is almost the same as the plain quote, except it allows expressions to be evaluated and their values interpolated into a quoted list with the comma and comma-at operators. If the variable snue has the value (bar baz) then `(foo ,snue) evaluates to (foo (bar baz)), while `(foo ,@snue) evaluates to (foo bar baz). The backquote is most frequently used in defining macro expansions.


Self-evaluating forms and quoted forms are Lisp's equivalent of literals. However, they are not necessarily constants. In some Lisp dialects it is possible to modify the values of literals in program code. For instance, if a function returns a quoted form, and the code that calls the function modifies the form, this may alter the behavior of the function on subsequent iterations.

 (defun should-be-constant '(one two three)) (let ((stuff (should-be-constant))) (setf (third stuff) 'bizarre)) ; bad! (should-be-constant) ; may return (one two bizarre) 

Modifying a quoted form like this is considered bad style, and the effects are undefined in some implementations because of compiler optimizations. When behavior like this is intentional, using a closure is the explicit way to do it. In programming languages, a closure is a function that refers to free variables in its lexical context. ...


Lisp's formalization of quotation has been noted by Douglas Hofstadter (in Gödel, Escher, Bach) and others as an example of the philosophical idea of self-reference. Douglas Richard Hofstadter (born February 15, 1945) is an American academic. ... Gödel, Escher, Bach: an Eternal Golden Braid: A metaphorical fugue on minds and machines in the spirit of Lewis Carroll (commonly GEB) is a Pulitzer Prize (1980)-winning book by Douglas Hofstadter, published in 1979 by Basic Books. ... The philosopher Socrates about to take poison hemlock as ordered by the court. ... A self-reference occurs when an object refers to itself. ...


Scope and closure

The modern Lisp family splits over the use of dynamic or static (aka lexical) scope. Scheme and Common Lisp make use of static scoping by default, while the more primitive Lisp systems used as embedded languages in Emacs and AutoCAD use dynamic scoping. In computer programming, scope is an enclosing context where values and expressions are associated. ... 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. ... AutoCAD is a suite of CAD software products for 2- and 3-dimensional design and drafting, developed and sold by Autodesk, Inc. ...


List structure of program code

A fundamental distinction between Lisp and other languages is that in Lisp, program code is not simply text. Parenthesized S-expressions, as depicted above, are the printed representation of Lisp code, but as soon as these are entered into a Lisp system they are translated by the parser (called the read function) into linked list and tree structures in memory.


Lisp macros operate on these structures. Because Lisp code has the same structure as lists, macros can be built with any of the list-processing functions in the language. In short, anything that Lisp can do to a data structure, Lisp macros can do to code. In contrast, in most other languages the parser's output is purely internal to the language implementation and cannot be manipulated by the programmer. Macros in C, for instance, operate on the level of the preprocessor, before the parser is invoked, and cannot re-structure the program code in the way Lisp macros can. C is a general-purpose, block structured, procedural, imperative computer programming language developed in 1972 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system. ... In computer science, a preprocessor is a program that processes its input data to produce output that is used as input to another program. ...


In simplistic Lisp implementations, this list structure is directly interpreted to run the program; a function is literally a piece of list structure which is traversed by the interpreter in executing it. However, most actual Lisp systems (including all conforming Common Lisp systems) also include a compiler. The compiler translates list structure into machine code or bytecode for execution. In computer science, an interpreter is a computer program that executes, or performs, instructions written in a computer programming language. ... Common Lisp, commonly abbreviated CL, is a dialect of the Lisp programming language, published in ANSI standard X3. ... Bytecode is a binary representation of an executable program designed to be executed by a virtual machine rather than by dedicated hardware. ...


Evaluation and the Read-Eval-Print Loop

Lisp languages are frequently used with an interactive command line, which may be combined with an integrated development environment. The user types in expressions at the command line, or directs the IDE to transmit them to the Lisp system. Lisp reads the entered expressions, evaluates them, and prints the result. For this reason, the Lisp command line is called a "read-eval-print loop", or REPL. A command line interface or CLI is a method of interacting with a computer by giving it lines of textual commands (that is, a sequence of characters) either from keyboard input or from a script. ... This article or section does not cite any references or sources. ... A read-eval-print loop (REPL) is a simple, interactive computer programming environment. ... ...


The basic operation of the REPL is as follows. This is a simplistic description which omits many elements of a real Lisp, such as quoting and macros.


The read function accepts textual S-expressions as input, and parses them into list structure. For instance, if you type the string (+ 1 2) at the prompt, read translates this into a linked list with three elements – the symbol +, the number 1, and the number 2. It so happens that this list is also a valid piece of Lisp code; that is, it can be evaluated. This is because the car of the list names a function – the addition operation.


The eval function evaluates list structure, returning some other piece of structure as a result. Evaluation does not have to mean interpretation; some Lisp systems compile every expression to native machine code. It is simple, however, to describe evaluation as interpretation: To evaluate a list whose car names a function, eval first evaluates each of the arguments given in its cdr, then applies the function to the arguments. In this case, the function is addition, and applying it to the argument list (1 2) yields the answer 3. This is the result of the evaluation. Evaluation is performed in applicative order. In functional programming languages, we are thinking of ourselves as recursively evaluating some mathematical expression. ...


It is the job of the print function to represent output to the user. For a simple result such as 3 this is trivial. An expression which evaluated to a piece of list structure would require that print traverse the list and print it out as an S-expression.


To implement a Lisp REPL, it is necessary only to implement these three functions and an infinite-loop function. (Naturally, the implementation of eval will be complicated, since it must also implement all special operators like if.) This done, a basic REPL itself is but a single line of code: (loop (print (eval (read)))).


Control structures

Lisp originally had very few control structures, but many more were added during the language's evolution. (Lisp's original conditional operator, cond, is the precursor to later if-then-else structures.)


Programmers in the Scheme dialect often express loops using tail recursion. Scheme's commonality in academic computer science has led some students to believe that tail recursion is the only, or the most common, way to write iterations in Lisp; this is incorrect. All frequently-seen Lisp dialects have imperative-style iteration constructs, from Scheme's do loop to Common Lisp's complex loop expressions. In computer science, tail recursion (or tail-end recursion) is a special case of recursion in which the last operation of the function is a recursive call. ...


Some Lisp control structures are special operators, equivalent to other languages' syntactic keywords. Expressions using these operators have the same surface appearance as function calls, but differ in that the arguments are not necessarily evaluated -- or, in the case of an iteration expression, may be evaluated more than once.


In contrast to most other major programming languages, Lisp allows the programmer to implement control structures using the language itself. Several control structures are implemented as Lisp macros, and can even be macroexpanded by the programmer who wants to know how they work.


Both Common Lisp and Scheme have operators for non-local control flow. The differences in these operators are some of the deepest differences between the two dialects. Scheme supports re-entrant continuations using the call/cc procedure, which allows a program to save (and later restore) a particular place in execution. Common Lisp does not support re-entrant continuations, but does support several ways of handling escape continuations. In computing, a continuation is a representation of some of the execution state of a program (often the call stack and the current Instruction pointer) at a certain point. ...


Frequently, the same algorithm can be expressed in Lisp in either an imperative or a functional style. As noted above, Scheme tends to favor the functional style, using tail recursion and continuations to express control flow. However, imperative style is still quite possible. The style preferred by many Common Lisp programmers may seem more familiar to programmers used to structured languages such as C, while that preferred by Schemers more closely resembles pure-functional languages such as Haskell. Haskell is a standardized purely functional programming language with non-strict semantics, named after the logician Haskell Curry. ...


Because of Lisp's early heritage in list processing, it has a wide array of higher-order functions relating to iteration over sequences. In many cases where an explicit loop would be needed in other languages (like a for loop in C) in Lisp the same task can be accomplished with a higher-order function. (The same is true of many functional programming languages.)


A good example is a function which in Scheme is called map and in Common Lisp is called mapcar. Given a function and one or more lists, mapcar applies the function successively to the lists' elements in order, collecting the results in a new list:

 (mapcar #'+ '(1 2 3 4 5) '(10 20 30 40 50)) 

This applies the + function to each corresponding pair of list elements, yielding the result (11 22 33 44 55).


Examples

Here are examples of Common Lisp code. While unlike Lisp programs used in industry, they are similar to Lisp as taught in computer science courses.


The basic "Hello world" program: A hello world program is a computer program that prints out Hello, world! on a display device. ...

 (print "Hello world") 
 (print (list 'Hello 'world)) 

As the reader may have noticed from the above discussion, Lisp syntax lends itself naturally to recursion. Mathematical problems such as the enumeration of recursively-defined sets are simple to express in this notation.


Evaluate a number's factorial: For factorial rings in mathematics, see unique factorisation domain. ...

 (defun factorial (n) (if (<= n 1) 1 (* n (factorial (- n 1))))) 

An alternative implementation, often faster than the previous version if the Lisp system has tail recursion optimization: In computer science, tail recursion (or tail-end recursion) is a special case of recursion in which the last operation of the function is a recursive call. ...

 (defun factorial (n &optional (acc 1)) (if (<= n 1) acc (factorial (- n 1) (* acc n)))) 

Contrast with an iterative version which uses Common Lisp's loop macro: Common Lisp, commonly abbreviated CL, is a dialect of the Lisp programming language, published in ANSI standard X3. ...

 (defun factorial (n) (loop for i from 1 to n for fac = 1 then (* fac i) finally (return fac))) 

The following function reverses a list. (Lisp's built-in reverse function does the same thing.)

 (defun -reverse (l &optional acc) (if (atom l) acc (-reverse (cdr l) (cons (car l) acc)))) 

Object systems

Various object systems and models have been built on top of, alongside, or into Lisp, including:

  • ObjectLisp[7] or Object Lisp, favored by Lisp Machines Incorporated
  • Loops (Lisp Object-Oriented Programming System) and the later CommonLoops
  • Flavors, built at MIT, and its descendant New Flavors, which were favored by Symbolics
  • The Common Lisp Object System, CLOS (descended from New Flavors and CommonLoops)
  • KR (short for Knowledge Representation), a constraints-based object system developed to aid the writing of Garnet, a GUI library for Common Lisp
  • KEE was written similarly, but incorporating an inference engine.[8]
  • Lush is an object-oriented lisp code with a goal of extensive programming capabilites, as it interfaces with many data libraries for math and science, but also interfaces with C code in-line, is still dynamic, and has graphics and hardware support.
  • SageCLOS, an Object Oriented Interface to AutoLISP invented by Ralph Gimenez

CLOS features multiple inheritance, multiple dispatch ("multimethods"), and a powerful system of "method combinations". In fact, Common Lisp, which includes CLOS, was the first object-oriented language to be officially standardized. Lisp Machines, Inc. ... CommonLoops (the Common Lisp Object-Oriented Programming System[1]; an acronym reminiscent of the earlier Lisp OO system Loops for the Interlisp-D system[2]) is an early program which extended Common Lisp to include Object-oriented programmingfunctionality and is a dynamic object system which differs radically from the OOP... Flavors, an early object-oriented extension to Lisp developed by Howard Cannon at the MIT Artificial Intelligence Laboratory for the Lisp machine, was the first programming language to include mixins. ... The Massachusetts Institute of Technology (MIT) is a private, coeducational research university located in Cambridge, Massachusetts. ... The Common Lisp Object System (CLOS) is the facility for object-oriented programming which is part of Common Lisp (CL). ... A constraint is a limitation of possibilities. ... Common Lisp, commonly abbreviated CL, is a dialect of the Lisp programming language, published in ANSI standard X3. ... IntelliCorp is a name used by multiple corporations: IntelliCorp (Software), company founded in 1980 and member of UML Partners; IntelliCorp (Security), provider of background checks for employment and other purposes. ... An inference engine tries to derive answers from a knowledge base. ... Look up Lush in Wiktionary, the free dictionary. ... Multiple inheritance refers to a feature of object-oriented programming languages in which a class can inherit behaviors and features from more than one superclass. ... Multiple dispatch or multimethods is the feature of some object-oriented programming languages in which a function or method can be specialized on the type of more than one of its arguments. ... Common Lisp, commonly abbreviated CL, is a dialect of the Lisp programming language, published in ANSI standard X3. ... Object-oriented programming (OOP) is a programming paradigm that uses objects and their interactions to design applications and computer programs. ...


Quotations

Wikiquote has a collection of quotations related to:
SQL, Lisp, and Haskell are the only programming languages that I've seen where one spends more time thinking than typing.
Philip Greenspun
I suppose I should learn Lisp, but it seems so foreign.
Paul Graham, November 1983
One can even conjecture that Lisp owes its survival specifically to the fact that its programs are lists, which everyone, including me, has regarded as a disadvantage.
John McCarthy, Inventor of Lisp, "Early History of Lisp"
Any sufficiently complicated C or Fortran program contains an ad-hoc, informally-specified bug-ridden slow implementation of half of Common Lisp.
Philip Greenspun, often called Greenspun's Tenth Rule of Programming[9]
Please don't assume Lisp is only useful for Animation and Graphics, AI, Bioinformatics, B2B and E-Commerce, Data Mining, EDA/Semiconductor applications, Expert Systems, Finance, Intelligent Agents, Knowledge Management, Mechanical CAD, Modeling and Simulation, Natural Language, Optimization, Research, Risk Analysis, Scheduling, Telecom, and Web Authoring just because these are the only things they happened to list.
Kent Pitman
Lisp has all the visual appeal of oatmeal with fingernail clippings mixed in.
Larry Wall, creator of the Perl programming language
LISP being the most powerful and cleanest of languages, that's the language that the GNU project always prefers.
Richard Stallman
the greatest single programming language ever designed
Alan Kay
[Emacs] is written in Lisp, which is the only computer language that is beautiful.
Neal Stephenson, In the Beginning...was the Command Line

Image File history File links This is a lossless scalable vector image. ... Wikiquote is a sister project of Wikipedia, using the same MediaWiki software. ... Philip Greenspun is a retired computer scientist who was a pioneer in developing online communities. ... Paul Graham For Paul Graham the photographer, see Paul Graham (photographer). ... 1983 (MCMLXXXIII in Roman) is a common year starting on Saturday of the Gregorian calendar. ... John McCarthy (born September 4, 1927, in Boston, Massachusetts, sometimes known affectionately as Uncle John McCarthy), is a prominent computer scientist who received the Turing Award in 1971 for his major contributions to the field of Artificial Intelligence. ... Philip Greenspun is a retired computer scientist who was a pioneer in developing online communities. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Kent M. Pitman is the President of HyperMeta, Inc. ... Larry Wall Larry Wall (born September 27, 1954) is a programmer, linguist, and author, most widely known for his creation of the Perl programming language in 1987. ... Programming Republic of Perl logo Perl, also Practical Extraction and Report Language (a backronym, see below), is a programming language released by Larry Wall on December 18, 1987 that borrows features from C, sed, awk, shell scripting (sh), and (to a lesser extent) from many other programming languages. ... Richard Matthew Stallman (born March 16, 1953), often abbreviated rms (lower case),[1] is a software freedom activist, hacker,[2] and software developer. ... Alan Curtis Kay (born May 17, 1940) is an American computer scientist, known for his early pioneering work on object-oriented programming and windowing graphical user interface design. ... 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. ... Neal Town Stephenson (born October 31, 1959) is an American writer, known primarily for his science fiction works in the postcyberpunk genre with a penchant for explorations of society, mathematics, currency, and the history of science. ... In the Beginning. ...

Notes

  1. ^ John McCarthy. Recursive Functions of Symbolic Expressions and Their Computation by Machine, Part I. Retrieved on 2006-10-13.
  2. ^ a b Tim Hart and Mike Levin. AI Memo 39-The new compiler. Retrieved on 2006-10-13.
  3. ^ David Canfield Smith. MLISP Users Manual. Retrieved on 2006-10-13.
  4. ^ The 36-bit word size of the PDP-6/PDP-10 was influenced by the usefulness of having two Lisp 18-bit pointers in a single word. "The PDP-6 project started in early 1963, as a 24-bit machine. It grew to 36 bits for LISP, a design goal." [1]
  5. ^ The Road To Lisp Survey. Retrieved on 2006-10-13.
  6. ^ Guy L Steele Jr, Richard P Gabriel. The evolution of Lisp. Retrieved on 2006-10-12.
  7. ^ pg 17 of Bobrow 1986
  8. ^ pg 108 of Veitch 1988
  9. ^ Phillip Greenspun. Research. Retrieved on 2006-10-13.

Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 286th day of the year (287th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 286th day of the year (287th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 286th day of the year (287th in leap years) in the Gregorian calendar. ... The PDP-6 (Programmed Data Processor-6) was a computer model developed by Digital Equipment Corporation (DEC) in 1963. ... 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... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 286th day of the year (287th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 285th day of the year (286th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 286th day of the year (287th in leap years) in the Gregorian calendar. ...

References

Peter H. Salus is a linguist, computer scientist, historian of technology, author and editor of books on computing. ... Transcript can have several meanings depending on the context used. ... Richard Matthew Stallman (born March 16, 1953), often abbreviated rms (lower case),[1] is a software freedom activist, hacker,[2] and software developer. ... October 28 is the 301st day of the year (302nd in leap years) in the Gregorian Calendar, with 64 days remaining. ... Also see: 2002 (number). ...

External links


  Results from FactBites:
 
Lisp programming language - Wikipedia, the free encyclopedia (5157 words)
Lisp is a family of computer programming languages with a long history and a distinctive fully-parenthesized syntax.
Lisp was used as the implementation of the programming language Micro Planner that was the foundation for the famous AI system SHRDLU.
Lisp was the first homoiconic programming language: the primary representation of program code is the same type of list structure that is also used for the main data structures.
LISP programming language - Wikipedia (940 words)
Lisp (coined from "list processing") is an early programming language with a simple prefix-notation syntax, dynamic typing (that is, untyped variables but typed values), and special features for processing lists.
In fact, there are now many different languages with "Lisp" in their names, and it is probably better to regard "Lisp" as the name of a family of languages rather than of a single language.
The language was invented by John McCarthy in 1958 whilst he was at MIT; he published a paper in CACM in 1960 titled "Recursive Functions of Symbolic Expressions and Their Computation by Machine, Part I" (part II was never published).
  More results at FactBites »

 
 

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