SML

Question 1

(T/F) In ML, programs are functions.

Answer 1

True

Question 2

(T/F) In ML, running a program is evaluating an expression.

Answer 2

True

Question 3

Do pure functional programming languages have assignment statements?

Answer 3

No

Question 4

In ML, do functions have types?

Answer 4

Yes

Primitive Type:

int, real, char, string, and bool.

Question 5

(T/F) In ML, types are not inferred.

Answer 5

False

Question 6

What is the type of the following function?

Answer 6

Question 7

What is the type of the following function?

Answer 7

‘a is a type variable.

‘a list is a list of whatever type ‘a is therefore size is a polymorphic function.

Question 8

What is a polymorphic function?

Answer 8

A funciton that works with many different types.

Question 9

In this example, what type does the plus sign default to?

Answer 9

This function defaults to int.

Question 10

What has to happen to override the type to a real value?

Answer 10

Question 11

What are curried functions?

Answer 11

Question 12

In ML, what is the purpose of the @ symbol?

Answer 12

Question 13

Give an example of a tuple in SML:

Answer 13

Question 14

Give an example of a list in SML:

Answer 14

Question 15

What is the keyword that declares a new variable and binds it to a value?

Answer 15

Question 16

Redefining Names:

Answer 16

Question 17

Declaring functions in SML:

Answer 17

Question 18

What keywords are used for recursive definitions?

Answer 18

Question 19

What does the Fun keyword do?

Answer 19

Question 20

Give an example of pattern matching:

Answer 20

Question 21

What is the type of

toString 1 = “one”


fun toString 0 = “zero”


| toString 2 = “two”;

Answer 21

val toString = fn: int -> string

Question 22

Pattern Matching Default Value:

Answer 22

Question 23

What is the type of

fun sumList [] = 0
| sumList (x :: xs) = x + sumList xs;

Answer 23

val sumList = fn : int list -> int

Question 24

What is the result of

fun sumList [] = 0
| sumList (x :: xs) = x + sumList xs;

if sumList [2,3,1]; is executed?

Answer 24

sumList [2,3,1];

= sumList (2::[3,1])
= 2 + sumList [3,1]
= 2 + sumList (3::[1])
= 2 + 3 + sumList (1::[])
= 2 + 3 + 1 + sumList []
= 2 + 3 + 1 + 0
= 6

val it = 6 :int

Question 25

Answer 25

Question 26

Results of executing the following definition:

Answer 26

Question 27

Answer 27

Question 28

A higher order function is a function that takes function as argument and/or returns a function as a result.

Answer 28

Question 29

What is the type of map?

Answer 29

Question 30

What is an alternative to a curry function?

Answer 30

Question 31

What is a benefit of curried functions?

Answer 31

Question 32

What is the type of the following curry function?

fun curry f x y = f (x,y);

Answer 32