Week 5

Question 1

What is a Number in Prolog?

Answer 1

A value that is either an Integer or a Float

Question 2

What is an Atom in Prolog?

Answer 2

A constant that does not have a numerical value

Begins with a lowercase letter or is quoted

eg.

buffallo

malcomX

“The X Files” - If you want spaces you must quote “”

Question 3

What is a Variable in Prolog?

Answer 3

A term that is to be determined

Starts with an uppercase letter or underscore

eg.

X

Author

Person_A

Question 4

What is a Compound Term in Prolog?

Answer 4

Consists of a functor followed by a sequence argument terms in brackets

eg.

dog(rover)

person(‘Swift’,6,9)

Question 5

What are Lists in Prolog?

Answer 5

Made up of elements (possibly of different type) enclosed in square brackets and separated by commas

eg. [2,3,4,5,6,7]

Question 6

How do you join lists in Prolog?

Answer 6

The cons (or “|”) notation allows one to represent a list as being constructed from some leading elements and a list

eg.

[1,2,3|[4,5]] -> makes [1,2,3,4,5]

Question 7

What is Backtracking in Prolog?

Answer 7

If any goal fails, the Prolog system tries to find another way of satisfying the most recently satisfied previous goal

This is known as backtracking