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Within LTS Haskell 24.6 (ghc-9.10.2)

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1. mapError :: (MonadError e m, MonadError e' n) => (m (Either e a) -> n (Either e' b)) -> m a -> n b

   can-i-haz	Control.Monad.Except.CoHas

   MonadError analogue of the mapExceptT function. The computation is unwrapped, a function is applied to the Either, and the result is lifted into the second MonadError instance.

2. mapExcept :: (Either e a -> Either e' b) -> Except e a -> Except e' b

   can-i-haz	Control.Monad.Except.CoHas

   Map the unwrapped computation using the given function.

   • runExcept (mapExcept f m) = f (runExcept
     m)

3. mapExceptT :: (m (Either e a) -> n (Either e' b)) -> ExceptT e m a -> ExceptT e' n b

   can-i-haz	Control.Monad.Except.CoHas

   Map the unwrapped computation using the given function.

   • runExceptT (mapExceptT f m) = f
     (runExceptT m)

4. mapReader :: (a -> b) -> Reader r a -> Reader r b

   can-i-haz	Control.Monad.Reader.Has

   Transform the value returned by a Reader.

   • runReader (mapReader f m) = f .
     runReader m

5. mapReaderT :: (m a -> n b) -> ReaderT r m a -> ReaderT r n b

   can-i-haz	Control.Monad.Reader.Has

   Transform the computation inside a ReaderT.

   • runReaderT (mapReaderT f m) = f .
     runReaderT m

6. mapAccumL :: forall acc x y (n :: Nat) . (acc -> x -> (acc, y)) -> acc -> Vec n x -> (acc, Vec n y)

   clash-prelude	Clash.Explicit.Prelude

   The mapAccumL function behaves like a combination of map and foldl; it applies a function to each element of a vector, passing an accumulating parameter from left to right, and returning a final value of this accumulator together with the new vector.

   >>> mapAccumL (\acc x -> (acc + x,acc + 1)) 0 (1 :> 2 :> 3 :> 4 :> Nil)
   (10,1 :> 2 :> 4 :> 7 :> Nil)
   

   "mapAccumL f acc xs" corresponds to the following circuit layout:

7. mapAccumR :: forall acc x y (n :: Nat) . (acc -> x -> (acc, y)) -> acc -> Vec n x -> (acc, Vec n y)

   clash-prelude	Clash.Explicit.Prelude

   The mapAccumR function behaves like a combination of map and foldr; it applies a function to each element of a vector, passing an accumulating parameter from right to left, and returning a final value of this accumulator together with the new vector.

   >>> mapAccumR (\acc x -> (acc + x,acc + 1)) 0 (1 :> 2 :> 3 :> 4 :> Nil)
   (10,10 :> 8 :> 5 :> 1 :> Nil)
   

   "mapAccumR f acc xs" corresponds to the following circuit layout:

8. mapAccumL :: forall acc x y (n :: Nat) . (acc -> x -> (acc, y)) -> acc -> Vec n x -> (acc, Vec n y)

   clash-prelude	Clash.Explicit.Prelude.Safe

   The mapAccumL function behaves like a combination of map and foldl; it applies a function to each element of a vector, passing an accumulating parameter from left to right, and returning a final value of this accumulator together with the new vector.

   >>> mapAccumL (\acc x -> (acc + x,acc + 1)) 0 (1 :> 2 :> 3 :> 4 :> Nil)
   (10,1 :> 2 :> 4 :> 7 :> Nil)
   

   "mapAccumL f acc xs" corresponds to the following circuit layout:

9. mapAccumR :: forall acc x y (n :: Nat) . (acc -> x -> (acc, y)) -> acc -> Vec n x -> (acc, Vec n y)

   clash-prelude	Clash.Explicit.Prelude.Safe

   The mapAccumR function behaves like a combination of map and foldr; it applies a function to each element of a vector, passing an accumulating parameter from right to left, and returning a final value of this accumulator together with the new vector.

   >>> mapAccumR (\acc x -> (acc + x,acc + 1)) 0 (1 :> 2 :> 3 :> 4 :> Nil)
   (10,10 :> 8 :> 5 :> 1 :> Nil)
   

   "mapAccumR f acc xs" corresponds to the following circuit layout:

10. mapM :: (Traversable t, Monad m) => (a -> m b) -> t a -> m (t b)

    clash-prelude	Clash.HaskellPrelude

    Map each element of a structure to a monadic action, evaluate these actions from left to right, and collect the results. For a version that ignores the results see mapM_.

    Examples

    mapM is literally a traverse with a type signature restricted to Monad. Its implementation may be more efficient due to additional power of Monad.

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