Rule based programming Language is used as a way to store a manipulate knowledge to interpret information in useful way. It is often used in AI (Artificial Intelligence) applications and research. The example of rule-based system is the domain-specific expert system that used rules to make deductions or choices.
For an example, an expert system help a teacher to choose a student based on the performance of the student in exams, activities or select tactical moves to play a game.
(object-class request ^action) (startup (strategy MEA) (make request ^action hello) ) (rule hello (request ^action hello) (write | Hello, world!| (crlf)) )