Prolog is a logical programming language that is often used to write expert systems. An expert system is a computer program that can mimic human reasoning in a specific domain. Expert systems are often used to solve problems that are difficult or impossible for humans to solve, such as medical diagnosis or financial planning.
To write a small Prolog engine or expert system, you first need to define the domain of the problem that you want to solve. This means defining the key concepts of the domain, the relationships between the concepts, and the rules that govern the domain. Once you have defined the domain, you can write the Prolog code that implements the expert system.
The Prolog code for an expert system consists of a set of facts and rules. Facts are statements that are true about the domain. Rules are statements that describe how the facts are related to each other. To solve a problem, the expert system starts with a set of facts and applies the rules to deduce new facts. The process continues until the expert system is unable to deduce a solution to the problem.
Here is an example of a small expert system that can be used to diagnose diseases. The domain of the problem is medicine and the key concepts are symptoms, diseases, and drugs. The rules describe how the symptoms are related to the diseases and how the diseases are related to the drugs. To diagnose a disease, the expert system starts with a set of symptoms and applies the rules to deduce the possible diseases. The expert system then provides a list of the possible diseases and the doctor can then select the most likely disease.
Writing a small Prolog engine or expert system is an interesting idea because it can be used to solve a wide range of problems. Expert systems can be used to solve problems that are difficult or impossible for humans to solve, such as medical diagnosis or financial planning. Additionally, expert systems can be used to automate tasks that are currently performed by humans, such as customer support or report generation.
Prolog code for a small expert system that can be used to infer family relationships
% Definitions of facts
father(john, peter).
father(john, paul).
mother(mary, peter).
% Definitions of rules
is_sibling(X,Y) :- father(Z,X), father(Z,Y), X\=Y.
is_child(X,Y) :- father(Y,X).
is_father(X,Y) :- father(X,Y).
is_mother(X,Y) :- mother(X,Y).
% Query
?- is_sibling(peter, paul).
true.
?- is_child(peter, john).
true.
?- is_father(john, peter).
true.
?- is_mother(mary, peter).
true.
If you are interested in writing a small Prolog engine or expert system, there are many resources available online. You can find tutorials, example code, and libraries that can help you get started.