Lisp

This article is about the programming language. For the speech disorder, see Lisp (impediment).

Lisp, created by John McCarthy in 1958, is one of the oldest extant, high-level computer programming languages, dating from the same era as Fortran and COBOL. Lisp takes its name from "List Processing", since one of its prominently featured data structures is the linked list. Lisp is still used, and sometimes taught, in universities, and has had enormous influence on the field of computer programming. Lisp derives some of its ideas from Alonzo Church's lambda calculus, although the language is not a literal implementation of that formalism. Features in the spirit of the lambda calculus are probably easiest to see in Scheme.

At McCarthy's request, the word Lisp now designates the family of languages that has resulted from his original design, and no longer any specific language, dialect, or implementation. For this reason, the American National Standards Institute (ANSI) relating to Lisp, X3.226/1994, is a standard for the language Common Lisp, in order that other members of the Lisp language family not be affected. Likewise, the ISO standard, ISO/IEC 13816:1997(E), defines a language named ISLISP.

Hello World

;;; This is an example of a Common Lisp program
;;; This defines a function, but does not call it.
;;; The call from another Lisp program would be: (hello-world)

(in-package "CL-USER")

(defun hello-world ()
  (write-line "Hello, world!"))

Language properties

The following list represents a series of powerful software language concepts in which Lisp was really the pioneer.

• Garbage collection/automatic storage management
• Dynamic typing
• Object Oriented Programming (Common Lisp Object System)
• Meta Object Protocol
• Self-contained compiler
• Source code as a data structure
• Closures

Others

• Marco system

Popular Myths About Lisp

Lisp is sometimes mischaracterized as an "interpreted" language. In fact, it has been true for several decades that all major Lisps have had compilers. Some very important and influential research in compiler design has been done in Lisp. For example, the notion of continuation-passing style was invented for Scheme.

Lisp is sometimes mischaracterized as a language that only has lists for container types. In fact, it has been true for several decades that all major Lisps have had a rich variety of container types, such as arrays, strings, hash tables, and user-defined class instances.

Members of the Lisp Language Family

There have been many members of the Lisp language family. Some of the more prominent Lisps are:

• BBN Lisp

• Eulisp
• Lisp 1.5
• INTERLISP
• MACLISP
• Portable Standard Lisp
• Zetalisp

Lisps in more recent use are:

• Autolisp
• Common Lisp
• Emacs Lisp
• ISLISP

Languages which found there origin in Lisp:

• Scheme
• Dylan
• Haskell

Significant Applications

Some of the many historically important applications that have been created in Lisp:

• ELIZA (emulator/parody of human therapist)
• MACSYMA (symbolic algebra)
• SHRDLU (natural language understanding)
• Lisp Machine (Lisp-based hardware and operating systems)

External Links

• Common Lisp HyperSpec
• Programming in Emacs Lisp
• ISLISP Programming Language
• Scheme Programming Language

References

• John McCarthy History of Lisp