nothing.hs

-- haskell syntax, btw

data Maybe a
  = Nothing
  | Just a

noStringHere :: Maybe String
noStringHere = Nothing

aStringHere :: Maybe String
aStringHere = Just "hello, chief"

handlePotentialNothingness :: Maybe String -> String
handlePotentialNothingness mStr =
  case mStr of
    Nothing -> "some default string"
    Just str -> str
    
    
data List a
  = Cons a (List a)
  | Nil
  
aList :: [a]
aList = [1,2,3]
-- [1,2,3]
-- 1 : 2 : 3 : []
-- 1 : ( 2 : ( 3 : [] ) )
-- 
-- where `:` is pronounced "cons"
-- and `[]` is pronounced "nil"
--
-- we could rewrite the above with `List`...

ourList :: List Int
ourList = Cons 1 (Cons 2 (Cons 3 Nil))