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

   errors	Control.Error

   Map the unwrapped computation using the given function.

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

2. mapMaybe :: (a -> Maybe b) -> [a] -> [b]

   errors	Control.Error

   The mapMaybe function is a version of map which can throw out elements. In particular, the functional argument returns something of type Maybe b. If this is Nothing, no element is added on to the result list. If it is Just b, then b is included in the result list.

   Examples

   Using mapMaybe f x is a shortcut for catMaybes $ map f x in most cases:

   >>> import GHC.Internal.Text.Read ( readMaybe )
   
   >>> let readMaybeInt = readMaybe :: String -> Maybe Int
   
   >>> mapMaybe readMaybeInt ["1", "Foo", "3"]
   [1,3]
   
   >>> catMaybes $ map readMaybeInt ["1", "Foo", "3"]
   [1,3]
   

   If we map the Just constructor, the entire list should be returned:

   >>> mapMaybe Just [1,2,3]
   [1,2,3]
   

3. mapMaybeT :: (m (Maybe a) -> n (Maybe b)) -> MaybeT m a -> MaybeT n b

   errors	Control.Error

   Transform the computation inside a MaybeT.

   • runMaybeT (mapMaybeT f m) = f (runMaybeT
     m)

4. mapII :: (a -> b) -> I a -> I b

   generics-sop	Generics.SOP

   Lift the given function.

5. mapIII :: (a -> b -> c) -> I a -> I b -> I c

   generics-sop	Generics.SOP

   Lift the given function.

6. mapM_ :: HashTable h => ((k, v) -> ST s b) -> h s k v -> ST s ()

   hashtables	Data.HashTable.Class

   A side-effecting map over the key-value records of a hash table. O(n).

7. mapM_ :: HashTable h => ((k, v) -> IO a) -> IOHashTable h k v -> IO ()

   hashtables	Data.HashTable.IO

   See the documentation for this function in mapM_.

8. mapM_ :: ((k, v) -> ST s b) -> HashTable s k v -> ST s ()

   hashtables	Data.HashTable.ST.Basic

   See the documentation for this function in mapM_.

9. mapM_ :: ((k, v) -> ST s a) -> HashTable s k v -> ST s ()

   hashtables	Data.HashTable.ST.Cuckoo

   See the documentation for this function in mapM_.

10. mapM_ :: ((k, v) -> ST s b) -> HashTable s k v -> ST s ()

    hashtables	Data.HashTable.ST.Linear

    See the documentation for this function in Data.HashTable.Class#v:mapM_.

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