11_FChaining.py

class Rule:
    def __init__(self, antecedents, consequent):
        self.antecedents = antecedents
        self.consequent = consequent
        
class KnowledgeBase:
    def __init__(self):
        self.facts = set()
        self.rules = []
        
    def add_fact(self, fact):
        self.facts.add(fact)
        
    def add_rule(self, rule):
        self.rules.append(rule)
        
    def apply_forward_chaining(self):
        new_facts_derived = True
        while new_facts_derived:
            new_facts_derived=False
            for rule in self.rules:
                if all(antecedents in self.facts for antecedents in rule.antecedents) and rule.consequent not in self.facts:
                    self.facts.add(rule.consequent)
                    new_facts_derived = True
                        
if __name__ == "__main__":
    kb = KnowledgeBase()
    rule1 = Rule(["A","C"],"E")
    rule2 = Rule(["A","E"],"G")
    rule3 = Rule(["A"],"E")
    rule4 = Rule(["G"],"D")
    kb.add_rule(rule1)
    kb.add_rule(rule2)
    kb.add_rule(rule3)
    kb.add_rule(rule4)
    kb.add_fact("A")
    kb.add_fact("C")
    kb.apply_forward_chaining()
    print("Derived Facts: ", kb.facts)