Haskell

Question 1

Instead of the + symbol, Haskell uses the symbol ANSWER for a string concatenation operator
.

Answer 1

++

Question 2

The type of a string constant in Haskell by default is written ANSWER.

Answer 2

[Char]

Question 3

In Haskell, you use the keyword ANSWER to collect related code into a similar scope.

Answer 3

module

Question 4

In Haskell, if I define a function double x = x + x its type signature would be ANSWER.

Answer 4

(Num a ) => a -> a

Question 5

In Haskell, instead of writing something like if x ==0 then 1 else fact (x-1)*x, you can write a series of lines starting with factorial 0 = 1. This second style is called ANSWER.

Answer 5

pattern matching

Question 6

In Haskell, instead of writing something like if x==0 then 1 else fact (x-1) x, you can write a series of lines starting with | x > 1 = x factorial (x-a). This second style is called ANSWER.

Answer 6

using guards

Question 7

In Haskell, instead of writing something like second x = head(tail(x)), you can write this without introducing the parameter x by using function composition. Doing that, you would define second by ANSWER.

Answer 7

second = head . tail

Question 8

In Haskell, if I write (h:t) = [3 , 5 ,7], ANSWER is the value of h.

Answer 8

3

Question 9

In Haskell, if I write (h:t) = [3, 5, 7], ANSWER is the value of t.

Answer 9

[5,7]

Question 10

In Haskell, ANSWER is the output of zip [17…20] [10 , 8 ….4].

Answer 10

[(17,10),(18,8),(19,6), (20,4)]

Question 11

In Haskell, ANSWER is the output of zip [20….17] [10,8…4]

Answer 11

[]

Default increment is 1 and zip only goes as far as shortest argument list

Question 12

In Haskell, the anonymous function ANSWER causes the expression ‘map ANSWER [1,2,3]’ to produce [-4, -5, -6].

Answer 12

(\x-> - (x+3))

Question 13

In Haskell, if we want to define a local named function inside a function definition, we use the keyword ANSWER.

Answer 13

where

Question 14

In Haskell, the type signature of the function sum x y = x + y is ANSWER.

Answer 14

(Num a ) => a -> a -> a

Question 15

In Haskell, given the definition sum x y = x + y, ANSWER is the value of that is produced by the expression (sum 3).

Answer 15

(\x -> 3 + x)

Question 16

The way Haskell handles functions with more than one parameter is called ANSWER.

Answer 16

currying

Question 17

In most languages, a function definition like f a b = a : (f (a + b) b) would result in an infinite recursion. However, in Haskell we can partially evaluate functions like this because Haskell is based on ANSWER.

Answer 17

lazy evaluation

Question 18

Although Haskell is a statically typed language, we usually don’t need to write type declarations because Haskell uses ANSWER to handle the matter.

Answer 18

type inference

Question 19

In Haskell, we can declare the type of a parameter to a function to be something specific like Num. However, we can also declare the type of a parameter to be something that could include many types like ListLike that supports the functions head and tail. We do this with a definition of ListLike that begins with the keyword ANSWER.

Answer 19

class

Question 20

One of the three most significant parts of a monad is called ANSWER, which wraps up a function and puts it in the container.

Answer 20

return

Question 21

One of the three most significant parts of a Haskell monad is called ANSWER, which unwraps up a function.

Answer 21

> > =

a bind function

Question 22

In Haskell’s do notation for working with monads, assignment uses the ANSWER operator.

Answer 22

(left arrow)

Question 23

Since Haskell doesn’t have traditional error handling mechanisms, by convention, people use the ANSWER monad to distinguish a valid return from an error return.

Answer 23

Maybe

This is similar to NaN’s usage in IEEE standard floating point arithmetic

Question 24

Haskell, defining lists using a notation like [x*2 | x (left arrow) [3,4,5]] is called using ANSWER.

Answer 24

list comprehesions

Question 25

In Haskell, [x*2 | x (left arrow) [3,4,5]] evaluates to ANSWER.

Answer 25

[6, 8, 10]