CODEWITHSUNDEEP
listhaskell
Alexandru Buliga
Alexandru Buliga

Reputation: 43

List of functions in Haskell

Supposedly I have those functions of the same type and result in Haskell:

add_one :: Integer -> Integer
add_one n = n + 1

multiply_by_five :: Integer -> Integer
multiply_by_five n = n * 5

subtract_four :: Integer -> Integer
subtract_four n = n - 4

add_ten :: Integer -> Integer
add_ten n = n + 10

How can I make a list from them so I can apply it to one single argument of Integer type such as:

map ($ single_argument) list_of_functions

?

Upvotes: 4

Views: 358

Answers (1)

Jacco Krijnen
Jacco Krijnen

Reputation: 367

Constructing lists with Haskel is done by using the (:) and [] list constructors, like so:

fList :: [Integer -> Integer]
fList = add_one : multiply_by_five : subtract_four : add_ten : []

-- or by using some syntactic sugar
fList' = [add_one, multiply_by_five, subtract_four, add_ten]

You can then indeed map application:

map ($ 3) fList

Upvotes: 10

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