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Changed directory: /home/hugo/Academic/Teaching/_Atual/TCPF/Aulas/
λ> :i Functor
type Functor :: (* -> *) -> Constraint
class Functor f where
  fmap :: (a -> b) -> f a -> f b
  (<$) :: a -> f b -> f a
  {-# MINIMAL fmap #-}
  	-- Defined in `GHC.Base'
instance Functor (Either a) -- Defined in `Data.Either'
instance Functor [] -- Defined in `GHC.Base'
instance Functor Solo -- Defined in `GHC.Base'
instance Functor Maybe -- Defined in `GHC.Base'
instance Functor IO -- Defined in `GHC.Base'
instance Functor ((->) r) -- Defined in `GHC.Base'
instance Functor ((,,,) a b c) -- Defined in `GHC.Base'
instance Functor ((,,) a b) -- Defined in `GHC.Base'
instance Functor ((,) a) -- Defined in `GHC.Base'
λ> :i Maybe
type Maybe :: * -> *
data Maybe a = Nothing | Just a
  	-- Defined in `GHC.Maybe'
instance Applicative Maybe -- Defined in `GHC.Base'
instance Eq a => Eq (Maybe a) -- Defined in `GHC.Maybe'
instance Functor Maybe -- Defined in `GHC.Base'
instance Monad Maybe -- Defined in `GHC.Base'
instance Semigroup a => Monoid (Maybe a) -- Defined in `GHC.Base'
instance Ord a => Ord (Maybe a) -- Defined in `GHC.Maybe'
instance Semigroup a => Semigroup (Maybe a)
  -- Defined in `GHC.Base'
instance Show a => Show (Maybe a) -- Defined in `GHC.Show'
instance MonadFail Maybe -- Defined in `Control.Monad.Fail'
instance Read a => Read (Maybe a) -- Defined in `GHC.Read'
instance Foldable Maybe -- Defined in `Data.Foldable'
instance Traversable Maybe -- Defined in `Data.Traversable'
λ> :i Maybe
type Maybe :: * -> *
data Maybe a = Nothing | Just a
  	-- Defined in `GHC.Maybe'
instance Applicative Maybe -- Defined in `GHC.Base'
instance Eq a => Eq (Maybe a) -- Defined in `GHC.Maybe'
instance Functor Maybe -- Defined in `GHC.Base'
instance Monad Maybe -- Defined in `GHC.Base'
instance Semigroup a => Monoid (Maybe a) -- Defined in `GHC.Base'
instance Ord a => Ord (Maybe a) -- Defined in `GHC.Maybe'
instance Semigroup a => Semigroup (Maybe a)
  -- Defined in `GHC.Base'
instance Show a => Show (Maybe a) -- Defined in `GHC.Show'
instance MonadFail Maybe -- Defined in `Control.Monad.Fail'
instance Read a => Read (Maybe a) -- Defined in `GHC.Read'
instance Foldable Maybe -- Defined in `Data.Foldable'
instance Traversable Maybe -- Defined in `Data.Traversable'
λ> :i Functor
type Functor :: (* -> *) -> Constraint
class Functor f where
  fmap :: (a -> b) -> f a -> f b
  (<$) :: a -> f b -> f a
  {-# MINIMAL fmap #-}
  	-- Defined in `GHC.Base'
instance Functor (Either a) -- Defined in `Data.Either'
instance Functor [] -- Defined in `GHC.Base'
instance Functor Solo -- Defined in `GHC.Base'
instance Functor Maybe -- Defined in `GHC.Base'
instance Functor IO -- Defined in `GHC.Base'
instance Functor ((->) r) -- Defined in `GHC.Base'
instance Functor ((,,,) a b c) -- Defined in `GHC.Base'
instance Functor ((,,) a b) -- Defined in `GHC.Base'
instance Functor ((,) a) -- Defined in `GHC.Base'
λ> x = Just 15
λ> (+5) x

<interactive>:14:1-6: error:
    * No instance for (Num (Maybe Integer)) arising from a use of `it'
    * In the first argument of `print', namely `it'
      In a stmt of an interactive GHCi command: print it
λ> fmap (+5) x
Just 20
λ> (+5) <$> x
Just 20
λ> :t <$>

<interactive>:1:1-3: error: parse error on input `<$>'
λ> :t (<$>)
(<$>) :: Functor f => (a -> b) -> f a -> f b
λ> :i (<$>)
(<$>) :: Functor f => (a -> b) -> f a -> f b
  	-- Defined in `Data.Functor'
infixl 4 <$>
λ> :i (4)

<interactive>:1:2: error: parse error on input `4'
λ> :i ($)
($) :: (a -> b) -> a -> b 	-- Defined in `GHC.Base'
infixr 0 $
λ> :i (+)
type Num :: * -> Constraint
class Num a where
  (+) :: a -> a -> a
  ...
  	-- Defined in `GHC.Num'
infixl 6 +
λ> :t fmap (+5)
fmap (+5) :: (Functor f, Num b) => f b -> f b
λ> :t fmap (+)
fmap (+) :: (Functor f, Num a) => f a -> f (a -> a)
λ> (+) <$> x
(+) <$> x :: Num a => Maybe (a -> a)
λ> y = Just 109
λ> x
Just 15
λ> :i Applicative
type Applicative :: (* -> *) -> Constraint
class Functor f => Applicative f where
  pure :: a -> f a
  (<*>) :: f (a -> b) -> f a -> f b
  GHC.Base.liftA2 :: (a -> b -> c) -> f a -> f b -> f c
  (*>) :: f a -> f b -> f b
  (<*) :: f a -> f b -> f a
  {-# MINIMAL pure, ((<*>) | liftA2) #-}
  	-- Defined in `GHC.Base'
instance Applicative (Either e) -- Defined in `Data.Either'
instance Applicative [] -- Defined in `GHC.Base'
instance Applicative Solo -- Defined in `GHC.Base'
instance Applicative Maybe -- Defined in `GHC.Base'
instance Applicative IO -- Defined in `GHC.Base'
instance Applicative ((->) r) -- Defined in `GHC.Base'
instance (Monoid a, Monoid b, Monoid c) =>
         Applicative ((,,,) a b c)
  -- Defined in `GHC.Base'
instance (Monoid a, Monoid b) => Applicative ((,,) a b)
  -- Defined in `GHC.Base'
instance Monoid a => Applicative ((,) a) -- Defined in `GHC.Base'
λ> :i fmap
type Functor :: (* -> *) -> Constraint
class Functor f where
  fmap :: (a -> b) -> f a -> f b
  ...
  	-- Defined in `GHC.Base'
λ> :i MyApplicative
type MyApplicative :: (* -> *) -> Constraint
class MyApplicative f where
  mypure :: a -> f a
  myapply :: f (a -> b) -> f a -> f b
  myliftA2 :: (a -> b -> c) -> f a -> f b -> f c
  {-# MINIMAL mypure, myapply, myliftA2 #-}
  	-- Defined at /home/hugo/Academic/Teaching/_Atual/TCPF/Aulas/Aula25.hs:6:1
λ> :t ($)
($) :: (a -> b) -> a -> b
λ> :t (<*>)
(<*>) :: Applicative f => f (a -> b) -> f a -> f b
λ> :t ($)
($) :: (a -> b) -> a -> b
λ> :t liftA2

<interactive>:1:1-6: error:
    * Variable not in scope: liftA2
    * Perhaps you meant `myliftA2' (line 9)
λ> :t liftA2
liftA2 :: Applicative f => (a -> b -> c) -> f a -> f b -> f c
λ> :i MyApplicative
type MyApplicative :: (* -> *) -> Constraint
class Functor f => MyApplicative f where
  mypure :: a -> f a
  myapply :: f (a -> b) -> f a -> f b
  myliftA2 :: (a -> b -> c) -> f a -> f b -> f c
  {-# MINIMAL mypure #-}
  	-- Defined at /home/hugo/Academic/Teaching/_Atual/TCPF/Aulas/Aula25.hs:8:1
λ> :i Applicative
type Applicative :: (* -> *) -> Constraint
class Functor f => Applicative f where
  pure :: a -> f a
  (<*>) :: f (a -> b) -> f a -> f b
  liftA2 :: (a -> b -> c) -> f a -> f b -> f c
  (*>) :: f a -> f b -> f b
  (<*) :: f a -> f b -> f a
  {-# MINIMAL pure, ((<*>) | liftA2) #-}
  	-- Defined in `GHC.Base'
instance Applicative (Either e) -- Defined in `Data.Either'
instance Applicative [] -- Defined in `GHC.Base'
instance Applicative Solo -- Defined in `GHC.Base'
instance Applicative NonEmpty -- Defined in `GHC.Base'
instance Applicative Maybe -- Defined in `GHC.Base'
instance Applicative IO -- Defined in `GHC.Base'
instance Applicative ((->) r) -- Defined in `GHC.Base'
instance (Monoid a, Monoid b, Monoid c) =>
         Applicative ((,,,) a b c)
  -- Defined in `GHC.Base'
instance (Monoid a, Monoid b) => Applicative ((,,) a b)
  -- Defined in `GHC.Base'
instance Monoid a => Applicative ((,) a) -- Defined in `GHC.Base'
λ> :i MyApplicative
type MyApplicative :: (* -> *) -> Constraint
class Functor f => MyApplicative f where
  mypure :: a -> f a
  myapply :: f (a -> b) -> f a -> f b
  myliftA2 :: (a -> b -> c) -> f a -> f b -> f c
  {-# MINIMAL mypure, myliftA2 #-}
  	-- Defined at /home/hugo/Academic/Teaching/_Atual/TCPF/Aulas/Aula25.hs:8:1
λ> :i MyApplicative
type MyApplicative :: (* -> *) -> Constraint
class Functor f => MyApplicative f where
  mypure :: a -> f a
  myapply :: f (a -> b) -> f a -> f b
  myliftA2 :: (a -> b -> c) -> f a -> f b -> f c
  {-# MINIMAL mypure, myapply #-}
  	-- Defined at /home/hugo/Academic/Teaching/_Atual/TCPF/Aulas/Aula25.hs:8:1
λ> :i MyApplicative
type MyApplicative :: (* -> *) -> Constraint
class Functor f => MyApplicative f where
  mypure :: a -> f a
  myapply :: f (a -> b) -> f a -> f b
  myliftA2 :: (a -> b -> c) -> f a -> f b -> f c
  {-# MINIMAL mypure #-}
  	-- Defined at /home/hugo/Academic/Teaching/_Atual/TCPF/Aulas/Aula25.hs:8:1
λ> :i MyApplicative
type MyApplicative :: (* -> *) -> Constraint
class Functor f => MyApplicative f where
  mypure :: a -> f a
  myapply :: f (a -> b) -> f a -> f b
  myliftA2 :: (a -> b -> c) -> f a -> f b -> f c
  {-# MINIMAL mypure, (myapply | myliftA2) #-}
  	-- Defined at /home/hugo/Academic/Teaching/_Atual/TCPF/Aulas/Aula25.hs:8:1
λ> validaNome "Malhada"
Just "Malhada"
λ> validaNome "Coalhada"
Nothing
λ> validaIdade (-20)
Nothing
λ> validaIdade (155)
Just 155
λ> validaArrobas 353453
Nothing
λ> :i Maybe
type Maybe :: * -> *
data Maybe a = Nothing | Just a
  	-- Defined in `GHC.Maybe'
instance Alternative Maybe -- Defined in `GHC.Base'
instance Applicative Maybe -- Defined in `GHC.Base'
instance Eq a => Eq (Maybe a) -- Defined in `GHC.Maybe'
instance Functor Maybe -- Defined in `GHC.Base'
instance Monad Maybe -- Defined in `GHC.Base'
instance MonadPlus Maybe -- Defined in `GHC.Base'
instance Semigroup a => Monoid (Maybe a) -- Defined in `GHC.Base'
instance Ord a => Ord (Maybe a) -- Defined in `GHC.Maybe'
instance Semigroup a => Semigroup (Maybe a)
  -- Defined in `GHC.Base'
instance Show a => Show (Maybe a) -- Defined in `GHC.Show'
instance MonadFail Maybe -- Defined in `Control.Monad.Fail'
instance Read a => Read (Maybe a) -- Defined in `GHC.Read'
instance Foldable Maybe -- Defined in `Data.Foldable'
instance Traversable Maybe -- Defined in `Data.Traversable'
λ> :i Vaca
type Vaca :: *
data Vaca
  = MkVaca {nome :: String, idade :: Integer, arrobas :: Integer}
  	-- Defined at /home/hugo/Academic/Teaching/_Atual/TCPF/Aulas/Aula25.hs:23:1
instance Eq Vaca
  -- Defined at /home/hugo/Academic/Teaching/_Atual/TCPF/Aulas/Aula25.hs:24:13
instance Show Vaca
  -- Defined at /home/hugo/Academic/Teaching/_Atual/TCPF/Aulas/Aula25.hs:24:17
λ> :t MkVaca
MkVaca :: String -> Integer -> Integer -> Vaca
λ> liftA3
liftA3
  :: Applicative f => (a -> b -> c -> d) -> f a -> f b -> f c -> f d
λ> liftA3 MkVaca
liftA3 MkVaca
  :: Applicative f => f String -> f Integer -> f Integer -> f Vaca
λ> cvf "Malhada" 15 100
Just (MkVaca {nome = "Malhada", idade = 15, arrobas = 100})
λ> cvf "Malhada" 300 100
Nothing
λ> cvf "Coalhada" 30 100
Nothing
λ> cvf "Coalhada" 30 1002342
Nothing
λ> cvf' "Coalhada" 30 1002342
Erro "minha v\243 n\227o gosta desse nome"
λ> cvf' "Coalhada" 30 1002342
Erro "minha vo n\227o gosta desse nome"
λ> cvf' "Coalhada" 30 1002342
Erro "minha vo nao gosta desse nome"
λ> cvf' "Malhada" 30 1002342
Erro "vaca estrela de neutron"
λ> cvf' "Malhada" 30234 1002342
Erro "vaca medieval"
λ> cvf' "Malhada" 30 10
OK (MkVaca {nome = "Malhada", idade = 30, arrobas = 10})
λ> f <$> x <*> y <*> z