Problem Solving Lab #3
Prolog

This lab is being done in order to help you learn various topics discussed in lecture. For attendance, you will all be asked to submit to try. You are not required to finish a lab you don't get done during lab time, although you may want to try some of the exercises to increase your understanding of the material.

Part I - The Basics

Background: Prolog stand for PROgramming in LOGic. And that's what it is. It is the reason we did a review of predicate logic last week. A lot of problems can be seen from a logical viewpoint - for instance, we might have a simple production system that helps to analyze problems that you might have with your car from its symptoms (does the car start, does it turn over, etc.).

Prolog survival commands:

• pl: The command to start our interpreter/compiler. We use SWI-Prolog on the Suns. The home page is a good source of information and contains links to several tutorials on Prolog.
• ['test']. : This loads a file named "test.pl". You can also use the consult('test') function.
• edit(test). : Edit the "test.pl" file.
• listing(child). : list child to screen
• trace(descendant). : trace descendant.
• trace(descendent,-all). : switch tracing off.
• halt. : exit to the command prompt.

Note that just like some of the regular Lisp commands didn't work under eLisp, some of the ordinary Prolog commands (untrace being one of them) don't work with our version of Prolog. If it doesn't work, don't be surprised. With that said, there is a nice list of basic commands available from a Prolog tutorial page.

Beyond survival, you need to know how to create facts and rules as well as how to ask questions. There are several good tutorial web sites that appear at the bottom of this page.

Go through sections 0 through 2 in this on-line tutorial . Do exercises 1, 3, and 6a.

Part II - Working with Recursion and Lists

Go through sections 3, 4, and 6 in the on-line tutorial . Do a couple of the simpler exercises to get the points in the tutorial.

Part III - A Simple Production System

Look at the simple production system (an example of an expert system) here . Try it out, look at it, understand it, and change it. Can you make it into your own simple expert system.

Submission

Each of you should submit (from your own account) to try an empty file called: here.txt. In order to create the file, type:

% touch here.txt

You will be told the command to use for submitting the file in your lab.

Each of you should submit (from your own account) a file called reflections.txt after the lab is over. The goal of the file is for you to reflect on what you have learned in the lab, what you had problems with, what I could do better next time, what you would have liked to do, and to give me feedback about the lab. In order to submit this file, type:

% try jdb-grd project44-1 reflections.txt

This file will be due this Thur. at midnight.