Intro to Clojure (L15)

Question 1

Clojure is designed as a modern dialect of what other language?

Answer 1

LISP

Question 2

Clojure is implemented on top of what virtual machine?

Answer 2

The Java Virtual Machine.

Question 3

Does Clojure have direct support for concurrency?

Answer 3

Yes.

Question 4

Clojure expressions are written in parenthesis, and are also called?

Answer 4

Forms.

Question 5

In Clojure, basic math operations use infix notation.

Answer 5

False, they use prefix notation (as all Clojure functions do).

Question 6

Clojure forms may be void, in that they return nothing.

Answer 6

False, Clojure expressions always return something.

Question 7

What is the name of Clojure’s command line interface, and what does it stand for?

Answer 7

REPL stands for READ-EVAL-PRINT-LOOP.

Question 8

What character is used to comment in Clojure?

Answer 8

The semi colon (;).

Question 9

What value is returned by Clojure’s print & println forms?

Answer 9

nil

Question 10

What are Clojure’s 5 primitive types?

Answer 10

Integer, float, string, boolean, and nil.

Question 11

Types are explicitly defined in Clojure.

Answer 11

False.

Question 12

Are Clojure’s boolean literals written in capitalized form, or all lowercase?

Answer 12

All lowercase.

Question 13

Are strings enclosed by single or double quotes in Clojure?

Answer 13

Double.

Question 14

Labels associated to values using the “def” function can be reassigned later.

Answer 14

They can be, but aren’t meant to be changed.

Question 15

Does the label, or the value come first following a call to “def”?

Answer 15

Label, then value.

Question 16

What is the difference between fn and defn in Clojure?

Answer 16

fn defines an anonymous function that may then be labelled using def. defn combines def and fn into one operation.

Question 17

How are values returned by functions in Clojure?

Answer 17

The value to be returned must be the final form in the function body.

Question 18

When using REPL, what will the following line output?
(fn [] “hello world”)

Answer 18

A representation of the function object.

Question 19

When using REPL, what will the following line output?
((fn [] “hello world”))

Answer 19

hello world

Question 20

Clojure’s if-form takes 2 other forms - a then-form and an else-form.

Answer 20

False, it must first take a boolean-form.

Question 21

Clojure’s else-form in an if-form is optional.

Answer 21

True.

Question 22

If the 3rd else-form is omitted from an “if” form, what is returned if the boolean-form evaluates to false?

Answer 22

nil

Question 23

What type of form can be used to group multiple “then” (or “else”) statements into a single expression?

Answer 23

the “do” form.

Question 24

Which expression in a “do” form is returned by that do form?

Answer 24

The last expression.

Question 25

What form combines the “if” and “do” forms?

Answer 25

The “when” form.

Question 26

The “when” form can also optionally accept an else-form.

Answer 26

False, it cannot accept an else-form at all.

Question 27

“When” forms always return nil when their conditions are false.

Answer 27

True.

Question 28

What are Clojure’s falsey values?

Answer 28

nil and false.

Question 29

What are Clojure’s truthy values?

Answer 29

Everything besides nil and false.