Value constructors in haskell

I have a question about Haskell. I'm new so I don't understand too well, but if anyone could help me I'd really appreciate. I have this exercise from a book that I bought.

Create a type Question with value contructors Sim or Nao. Make a function that:

• listQuest: receive from a parameter a list of Questions and return 0 for Nao or 1 for Sim corresponding the constructors in the list.

I tried this code:

module Question where 

data Question = Yes | No deriving Show

questNum :: Question -> Int
questNum No = 0
questNum Yes = 1

listQuest :: [Question] -> [Int]
listQuest listQuestion =  [ questNum quest | quest <- listQuestion ]

I'm lost in the prompt matter. Don't know what to write to use the function.

Thanks for the help

There are several ways to do that, you did it by list comprehension, another way is using map:

listQuest :: [Question] -> [Int]
listQuest xs = map questNum  xs

shorter

listQuest :: [Question] -> [Int]
listQuest  = map questNum  

using foldr (it is also a way to say map, indeed you can write the general map using foldr):

listQuest :: [Question] -> [Int]
listQuest = foldr (\x rs -> questNum x : rs) []

and the old good pattern matching (is map, but with pattern matching):

listQuest :: [Question] -> [Int]
listQuest []  = []
listQuest (x:xs) = questNum x : listQuest xs  

your way, and all of this, are equivalent.

On the prompt:

Then on the prompt you type something like:

$> :l file_name.hs
$> listQuest [Yes, Yes, No]
$> [1,1,0]