Lisp

Lisp, created by John McCarthy in 1958, is the second-oldest high-level computer programming language. Only FORTRAN is older. Lisp takes its name from "List Processing", since one of its prominently featured data structures is the linked list.

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!"))

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 arrays, strings, and user-defined structures or classes.

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

Lisps in more recent use are:

• Autolisp
• Common Lisp
• Emacs Lisp
• ISLISP
• Scheme

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