Ivan-Bratko-Prolog-Examples

PROLOG PROGRAMMING FOR ARTIFICIAL INTELLIGENCE (by lvan Bratko, E.Kardelj University. J.Stefan Institute Yugoslavia [1])

Chapter 1

• Prolog programming consists of relations, clauses(facts, rules and questions) and queries.
• A relation can be specified by facts, simply stating the n-tuples of object, or by stating rules about the relation.
• A procedure is a set of clauses about the same relation.
• To satisfy a query, involves logical inference, exploring among alternatives and backtracking. All this is done automatically by the Prolog system and is, in principle, hidden from the user.
• Also about whether goal is satisfiable or not.

Chapter 2

• Simple objects in Prolog are atoms, variables and numbers.
• Structures are constructed by means of functors. Each functor is defined by its name and arity.
• The lexical scope of variables is one clause. Thusthe same variable name in two clauses means two different variables.
• Structures can be seen as trees
• The matching operation takes two terms and tries to make them identical
• A comma between goals means the conjunction of goals. A semicolon means disjunction of goals.
• The procedural meaning does depend on the order of goals and clauses. Thus the order can affect the efiiciency of the program. A order may even lead to infinite recursive calls.

Chapter 3

• The list is a frequently used structure consists of a head and a tail which is a list as well.
• Common operations on lists are: list membership, concatenation, adding an item, deleting an item, sublist
• The operator notation allows the programmer to tailor the syntax of programs toward particular needs. Using operators the readability of programs can be greatly improved.
• Arithmetic is done by built-in procedures. Evaluation of an arithmetic expressionis forced by the procedure is and by the comparison predicates <, =<, etc

Chapter 4

• A database can be naturally represented as a set of Prolog facts.
• Prolog's mechanisms of querying and matching can be flexibly used for retrievirg structured information from a database.
• Abstract mathematicalconstructs,such as automata, can often be readily translated into executable Prolog definitions.

Chapter 5

• Cut facility prevents backtracking.
• It is used both to improve the efficiency of programs and to enhance the expressive power of the language, by not exploring the alternatives.
• Cut makes it possible to through rules of the form: if Condition then Conclusion1 otherwise Conclusion2
• Goals true always succeeds,fail always fails.
• Inserting a cut may destroy the correspondence between the declarative and procedural meaning of a program. Use with care.

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Running queries (in SWI - Prolog or command line):

$ swipl -s chapter1-5.pl -g "solution3(12,S)"
$ swipl -s chapter1-5.pl -g "permutation([a,b,c,d], P)"

Book Excercises can be found here:

• https://github.com/dc-mak/Prolog
• https://github.com/okanvk/Prolog-Exercises

Other good examples:

• https://github.com/Anniepoo/prolog-examples

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[1] Ivan Bratko. Prolog Programming for Artificial Intelligence, 1986

@book{Bratko:1986:PPA:6981,
    author = {Bratko, Ivan},
    title = {Prolog Programming for Artificial Intelligence},
    year = {1986},
    isbn = {0-201-14224-4},
    publisher = {Addison-Wesley Longman Publishing Co., Inc.},
    address = {Boston, MA, USA},
}