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1. mapInstr :: forall instr1 instr2 (m :: Type -> Type) a . Monad m => (forall x . () => instr1 x -> instr2 x) -> ProgramT instr1 m a -> ProgramT instr2 m a

   operational	Control.Monad.Operational

   Extend a mapping of instructions to a mapping of ProgramT.

2. mapUnliftedArray :: (PrimUnlifted a, PrimUnlifted b) => (a -> b) -> UnliftedArray a -> UnliftedArray b

   primitive-unlifted	Data.Primitive.Unlifted.Array

   Map over the elements of an UnliftedArray.

3. mapUnliftedArray :: (PrimUnlifted a, PrimUnlifted b) => (a -> b) -> UnliftedArray a -> UnliftedArray b

   primitive-unlifted	Data.Primitive.Unlifted.Array.ST

   Map over the elements of an UnliftedArray.

4. mapSmallUnliftedArray :: (PrimUnlifted a, PrimUnlifted b) => (a -> b) -> SmallUnliftedArray a -> SmallUnliftedArray b

   primitive-unlifted	Data.Primitive.Unlifted.SmallArray

   Map over the elements of an SmallUnliftedArray.

5. mapSmallUnliftedArray :: (PrimUnlifted a, PrimUnlifted b) => (a -> b) -> SmallUnliftedArray a -> SmallUnliftedArray b

   primitive-unlifted	Data.Primitive.Unlifted.SmallArray.ST

   Map over the elements of an SmallUnliftedArray.

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

   protolude	Protolude

   Map the unwrapped computation using the given function.

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

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

   protolude	Protolude

   Map the unwrapped computation using the given function.

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

8. mapException :: (Exception e1, Exception e2) => (e1 -> e2) -> a -> a

   protolude	Protolude

   This function maps one exception into another as proposed in the paper "A semantics for imprecise exceptions".

9. mapM_ :: (Foldable t, Monad m) => (a -> m b) -> t a -> m ()

   protolude	Protolude

   Map each element of a structure to a monadic action, evaluate these actions from left to right, and ignore the results. For a version that doesn't ignore the results see mapM. mapM_ is just like traverse_, but specialised to monadic actions.

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

    protolude	Protolude

    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]
    

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