What is Prolog?

Prolog is a logic programming language, which has an association with artificial intelligence and computational linguistics.
It is designed by Alain Colmerauer who is a French computer scientist in 1972.
Prolog’s major implementations: BProlog, ECLiPSe, Ciao Prolog, GNU Prolog, Quintus, SICStus, Strawberry, SWI-Prolog, YAP-Prolog, tuProlog
Prolog’s dialects: ISO Prolog, Edinburgh Prolog


Having its roots in formal logic, and unlike many other programming languages, Prolog is declarative.
The program logic is expressed in terms of relations, and execution is triggered by running queries over these relations.
Relations and queries are constructed using Prolog's single data type, the term.
Relations are defined by clauses.

Clauses are statements about what is true about a problem, instead of instructions how to accomplish the solution, the Prolog system uses the clauses to work out how to accomplish the solution by searching through the space of possible solutions.