Maybes.elm

type alias Test =
    { a: Int
    , b: String
    }

foo : Test
foo = { a = 1, b = "f" }

foo

Just foo

Nothing

Ok foo

Err foo

Err "Error with Message"

type TestApp e x f = TestApp e x f

a : TestApp String Int Test
a = TestApp "f" 2 { a = 3, b = "c" }

a

t : Float -> Int -> Maybe (Float, Int)
t n z = Just ( n, z )

t