Extracting a list of values from a list of maybes without fromJust

Question

Input: [Just "foo", Just "bar", Nothing, Just "quux"]

Output: ["foo", "bar", "quux"]

I'm not satisfied with the following solution using fromJust because it's not very portable to elm which doesn't like unsafe functions:

extract list = map fromJust $ filter isJust list

Is there another concise / idiomatic way to achieve this?

Answer 1

You can use catMaybes:

import Data.Maybe
catMaybes list

Answer 2

Λ: :m + Data.Maybe
Λ: concatMap maybeToList [Just "foo", Just "bar", Nothing, Just "quux"]
["foo","bar","quux"]