Picat General 2

Question 1

Which operator is used in Picat to unify two terms?

Accepted Answer

=

Answer

The = operator performs unification in Picat, binding variables so both sides become identical.

Question 2

What does the `not` predicate do in Picat?

Accepted Answer

Negation as failure — succeeds if goal fails

Answer

In Picat, `not(Goal)` succeeds when Goal fails and fails when Goal succeeds, implementing negation-as-failure.

Question 3

What is the role of the `module` declaration in a Picat source file?

Accepted Answer

Defines a namespace for predicates and functions

Answer

A `module` declaration names the compilation unit and controls which predicates are exported as part of Picat's module system.

Question 4

In Picat, what symbol introduces a clause head-body separator in a rule?

Accepted Answer

=>

Answer

Picat uses `=>` (fat arrow) as the clause separator between the head pattern/guard and the body of a rule.

Question 5

Which built-in predicate checks whether a term is a free (uninstantiated) variable in Picat?

Accepted Answer

var(X)

Answer

`var(X)` succeeds when X is an uninstantiated variable, following the standard logic-programming convention.

Picat Practice Test