Prolog for PCs

• Prolog is freely available from SWI-Prolog.
• pl will be installed by default to c:\\program files\pl

Useful Prolog Tidbits

• Prolog source files typically have a suffix of .pl
• You can break a list apart using [a|b] where a denotes the first item in the list and b denotes the rest of the list.
• To test for inequality, use \=
• not is a built-in Prolog predicate.
• The underscore ( _ ) represents an anonymous variable.

Prolog Environment Commands

• consult('file-name').
• pwd.
• ls.
• cd(directory).
• edit.
• emacs.
• make.
• trace.
• apropos(word).
• help(word).
• halt.

Examples

• likes.pl
• examples.pl

11/30 Exercises (Remember to meet in EPS 254)

1. Construct a Prolog genealogy database that covers 3 generations of your family. You may use the following facts in your database: male(x), female(x), and parent(x, y) where x is the parent of y.
   • Define mother(X,Y).
   • Define father(X,Y).
   • Define grandmother(X,Y).
   • Define grandfather(X,Y).
   • Define allgrandparents(X). This predicate should find and print all grandparents of X.
   • Define sibling(X,Y). Make sure that a person is not his or her own sibling!
   • Define allsiblings(X). This predicate should find and print all siblings of X.
   • Define aunt(X,Y).
   • Define uncle(X,Y).
2. Define your own Prolog predicate that determines whether an element is a member of a list.