Re: [Haskell-cafe] lens and Maybe value

20 Dec 2022


      import           Control.Lens                       (makeLenses)

data A = A { _a = (Maybe Int) }

makeLenses A

myA = A Nothing

ma = Just 1

newA = case ma of
         Nothing -> myA
         (Just _) -> (a .~ ma) myA

Re: [Haskell-cafe] lens and Maybe value

PICCA Frederic-Emmanuel