expert-system-shell

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Halal-Bot Is Smarter Than You!

Authors: Matthew Kearns and Ahmed Youssef.

Brief Explanation:

This is a simple expert system that learns information to answer questions about its behavior. It uses forward-chaining to learn new rules given user-supplied rules and variables (either root or learned), and it uses backward-chaining to create explanations for its behavior given the values of the variables in the system and the learned rules.

The difference between a root variable and a learned variable:

A root variable is a variable whose truth value is known by the user, and the user can set its value to either true or false. The truth value of a learned variable, however, depends on the rules of the system and the values of the root variables that it depends on.

Usage Instructions:

1. Teach [-R/-L] Var = String

	Teaches the system the type and value of a variable.
	
2. Teach Var = [True/False]

	Teaches the system the truth value of the variable.
	
3. Teach Expression -> Var

	Teaches the system a new rule.
	
4. List

	Lists the values of all root and learned variables, and
	lists all of the current rules and learned rules in the
	system.
	
5. Learn

	Creates new rules based on rules already supplied in the system
	and updates the truth values of the variables based on the rules.
	
6. Query Expression

	Query returns the truth value of the expression based on all of 
	the current rules and variables in the system.
	
7. Why Expression

	Why gives an explanation of why the user-supplied expression is true
	or false given the current rules and variable values held by the
	system.
	
Key:

-R = root variable
-L = learned variable
Var = user-defined variable name
String = A string of the form "Today is Monday" or "Matt likes ice cream"
Expression = Any valid expression of the form A&B->C or (!((A|B))&C)->D