Hoogle Search
Within LTS Haskell 24.52 (ghc-9.10.3)
Note that Stackage only displays results for the latest LTS and Nightly snapshot. Learn more.
bimap :: Bifunctor p => (a -> b) -> (c -> d) -> p a c -> p b dprotolude Protolude.Bifunctor No documentation available.
fmap :: Functor f => (a -> b) -> f a -> f bprotolude Protolude.Functor fmap is used to apply a function of type (a -> b) to a value of type f a, where f is a functor, to produce a value of type f b. Note that for any type constructor with more than one parameter (e.g., Either), only the last type parameter can be modified with fmap (e.g., b in `Either a b`). Some type constructors with two parameters or more have a Bifunctor instance that allows both the last and the penultimate parameters to be mapped over.
Examples
Convert from a Maybe Int to a Maybe String using show:>>> fmap show Nothing Nothing >>> fmap show (Just 3) Just "3"
Convert from an Either Int Int to an Either Int String using show:>>> fmap show (Left 17) Left 17 >>> fmap show (Right 17) Right "17"
Double each element of a list:>>> fmap (*2) [1,2,3] [2,4,6]
Apply even to the second element of a pair:>>> fmap even (2,2) (2,True)
It may seem surprising that the function is only applied to the last element of the tuple compared to the list example above which applies it to every element in the list. To understand, remember that tuples are type constructors with multiple type parameters: a tuple of 3 elements (a,b,c) can also be written (,,) a b c and its Functor instance is defined for Functor ((,,) a b) (i.e., only the third parameter is free to be mapped over with fmap). It explains why fmap can be used with tuples containing values of different types as in the following example:>>> fmap even ("hello", 1.0, 4) ("hello",1.0,True)concatMapM :: Monad m => (a -> m [b]) -> [a] -> m [b]protolude Protolude.Monad No documentation available.
-
No documentation available.
-
reflex Data.AppendMap Deprecated: Use MonoidalMap instead
pattern
AppendMap :: Map k v -> MonoidalMap k vreflex Data.AppendMap Deprecated: Use MonoidalMap instead
_unAppendMap :: MonoidalMap k v -> Map k vreflex Data.AppendMap Deprecated: Use getMonoidalMap instead
-
No documentation available.
-
reflex Data.FastMutableIntMap A FastMutableIntMap holds a map of values of type a and allows low-overhead modifications via IO. Operations on FastMutableIntMap run in IO.
-
reflex Data.FastMutableIntMap Patch for IntMap which represents insertion or deletion of keys in the mapping. Internally represented by 'IntMap (Maybe a)', where Just means insert/update and Nothing means delete.