Picat Imperative Programming Constructs 5

Question 1

Which Picat construct is used to handle runtime exceptions in imperative code?

Accepted Answer

try ... catch ... end

Answer

Picat uses try ... catch(Pattern) ... end blocks to intercept and handle exceptions.

Question 2

What does `string_to_atom(S)` do when used in a Picat imperative function?

Accepted Answer

Converts a string (char list) to an atom

Answer

string_to_atom/1 converts a Picat string (list of character codes or chars) into an atom.

Question 3

How do you concatenate two lists in Picat within an imperative function?

Accepted Answer

L1 ++ L2

Answer

The ++ operator performs list concatenation in Picat, returning a new combined list.

Question 4

In Picat's imperative mode, what does `X @= Y` mean?

Accepted Answer

X is assigned the value of Y only if X is unbound

Answer

The @= operator in Picat assigns Y to X only when X is an unbound (free) variable, leaving it unchanged otherwise.

Question 5

What is the output of the Picat code: `X := 3, (X > 2 -> Y := "big" ; Y := "small"), print(Y)`?

Accepted Answer

big

Answer

Since X is 3 which is greater than 2, the then-branch executes and Y is assigned "big", which is then printed.

Picat Practice Test