Prolog Homework

Note, your textbook is online at http://www.learnprolognow.org

All the sample databases can be found at: http://home.adelphi.edu/~pe16132/csc270/note/prologExercises.htm (You will dowload the knowledgebase as ?.x but change it to .pl).

Write a list of facts that are points on a graph (ex: point(1,3).)

• Sample fact: point(1,3).
• Add at least 6 more.

Write a rule that determines whether a line going through 2 points is horizontal. A Horizontal line requires that the Y value be the same. The X value must be different.

• The planned query is horizontal (X1,Y1,X2,Y2).
• This means that horizontal(4 variables ) needs to be the head (left part) of a rule, and the body (right side of the rule) needs to include rules about point( ? , ?).
• The head is followed by :- and then the facts that must be true.
• Example: jealousy(X,Y) :- loves(X,A), loves (Y,A), not (X = Y).

Write another rule that determines whether a line going through 2 points is vertical.

Save the file with a .pl extension.

Open a prolog session on panther (swipl)

consult your knowledgebase by typing [your filename without the .pl].

list the knowledgebase using : listing.

• see all the lines in your .pl file

Run a query to see all the points in your knowledgebase that start with X=1.

• Example: To find all the loves which had love object = Amy, you ran the query loves(X,Amy).

Run a query to test two points in your knowledgebase:

• ex: horizontal(2,1,5,1). (Assuming you have facts point(2,1) and point (5,1)). should be true
• ex: horizontal(1,2,3,5). (Assuming you have facts point(1,2) and point (3,5)). should be false
• If you cannot get this part to work, hand it in anyway. This is hard.

Run these queries that show all the possible horizontal lines made with the points in the database: horizontal (X1,Y1,X2,Y2). . Repeat for vertical (X1,Y1,X2,Y2).

• A will bind to a point(? , ?) and B will bind to another point(? ?).
• type ; to keep getting all the answers
• If you cannot get this last part to work, hand it in anyway. This last step is hard.

copy everything you ran in your prolog session from your terminal into a notepad file and upload that fille to moodle.