Using Maybe type in Haskell

Question

I\'m trying to utilize the Maybe type in Haskell. I have a lookup for key, value tuples that returns a Maybe. How do I access the data that was wrapped by Maybe? For exam

Answer 1

Just as a side note: Since Maybe is a Monad, you can build computations using do-notation ...

sumOfThree :: Maybe Int
sumOfThree = do
  a <- someMaybeNumber
  b <- someMaybeNumber
  c <- someMaybeNumber
  let k = 42 -- Just for fun
  return (a + b + c + k)