Getting Started

Prolog is the most widely used programming language to have been inspired by logic programming research. There are a number of reasons for the popularity of Prolog as a programming language: Powerful symbol manipulation facilities, including unification with logical variables. Programmers can consider logical variables as names ‘holes’ in data structures. Unification also serves as the parameter passing mechanism, and provides a constructor and selector of data structures. When combined with recursive procedures and a surface syntax for data structures, the simple manipulation possibilities of Prolog surpass those of other languages.Automatic backtracking provides generate-and-test as the basic control flow model. This is more general than the strict unidirectional sequential flow of control in conventional languages. Although generate-and-test is not appropriate for some applications, other control flow models can be programmed to correspond to the demands of a particular application.Program clauses and data structures have the same form. This gives a unified model for representing data as programs and programs as data. Other languages such as Lisp also have this features.