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(often US), prolog
a. the prefatory lines introducing a play or speech
b. the actor speaking these lines
2. in early opera
a. an introductory scene in which a narrator summarizes the main action of the work
b. a brief independent play preceding the opera, esp one in honour of a patron


(computer science)
A programming language that is for artificial intelligence applications, and uses problem descriptions to reach solutions, based on precise rules.


Programming in Logic or (French) Programmation en Logique. The first of the huge family of logic programming languages.

Prolog was invented by Alain Colmerauer and Phillipe Roussel at the University of Aix-Marseille in 1971. It was first implemented 1972 in ALGOL-W. It was designed originally for natural-language processing but has become one of the most widely used languages for artificial intelligence.

It is based on LUSH (or SLD) resolution theorem proving and unification. The first versions had no user-defined functions and no control structure other than the built-in depth-first search with backtracking. Early collaboration between Marseille and Robert Kowalski at University of Edinburgh continued until about 1975.

Early implementations included C-Prolog, ESLPDPRO, Frolic, LM-Prolog, Open Prolog, SB-Prolog, UPMAIL Tricia Prolog. In 1998, the most common Prologs in use are Quintus Prolog, SICSTUS Prolog, LPA Prolog, SWI Prolog, AMZI Prolog, SNI Prolog.

ISO draft standard at Darmstadt, Germany. or UGA, USA.

See also negation by failure, Kamin's interpreters, Paradigms of AI Programming, Aditi.

A Prolog interpreter in Scheme.

A Prolog package from the University of Calgary features delayed goals and interval arithmetic. It requires Scheme with continuations.

["Programming in Prolog", W.F. Clocksin & C.S. Mellish, Springer, 1985].


(PROgramming in LOGic) A programming language used for developing AI applications (natural language translation, expert systems, abstract problem solving, etc.). Developed in France in 1973, "Programmation en Logique" is used throughout Europe and Japan and has gained popularity in the U.S.

Similar to LISP, it deals with symbolic representations of objects. The following example, written in University of Edinburgh Prolog, converts Fahrenheit to Celsius:

  convert:- write('Enter Fahrenheit'),
   write('Celsius is '),
   Cent is (5 * (Fahr - 32)) / 9,
References in periodicals archive ?
For additional information about the Chinese localized version of Prolog software offered by ProjectAIMS, visit their website at http://www.
Now that I have loaded my Prolog database, I need to feed it some more information.
In the Business of Projects since 1993, MPS offers both software and ASP-based tools, including the award-winning Prolog Application Suite and ProjectTalk.
On the other hand, PARLOG is less expressive, and it is impossible to write a simple Prolog metainterpreter in the language.
That choice is clear and could be made instantly without computer assistance, but the steps taken will show how Prolog works.
Concurrent Prolog) The core part of KL1 should be based on Concurrent Prolog, but should support search problems and metaprogramming as well.
I argued for Concurrent Prolog because it did actors so well, and it seemed clear to me that actors should be the base concept for programming parallel machines.
Concerning the characteristics of the language, Prolog is often compared with its major competitor Lisp.