lens-op-ob-setexamples.hs

setExamples :: IO ()
setExamples = do
  let bob = User (UserName "bob") 0 Nothing HM.empty

  print "Bob, with an updated score"
  print $ set score 42 bob
  -- User {_userName = UserName "bob", _userScore = 42, _userPet = Nothing, _userInventory = fromList []}
  print $ (score .~ 42) bob
  -- User {_userName = UserName "bob", _userScore = 42, _userPet = Nothing, _userInventory = fromList []}

  -- print bob with score set to 42
  print $ bob & score .~ 42
  -- User {_userName = UserName "bob", _userScore = 42, _userPet = Nothing, _userInventory = fromList []}