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firstTraversing :: Traversing p => p a b -> p (a, c) (b, c)profunctors Data.Profunctor.Traversing No documentation available.
firstA :: (Bitraversable t, Applicative f) => (a -> f c) -> t a b -> f (t c b)base-compat Data.Bitraversable.Compat Traverses only over the first argument.
firstA f ≡ bitraverse f pure
firstJustM :: Monad m => (a -> m (Maybe b)) -> [a] -> m (Maybe b)extra Control.Monad.Extra Like findM, but also allows you to compute some additional information in the predicate.
firstJustM :: (Foldable f, Monad m) => (a -> m (Maybe b)) -> f a -> m (Maybe b)extra Data.Foldable.Extra A generalization of firstJustM to Foldable instances.
firstJust :: (a -> Maybe b) -> [a] -> Maybe bextra Data.List.Extra Find the first element of a list for which the operation returns Just, along with the result of the operation. Like find but useful where the function also computes some expensive information that can be reused. Particular useful when the function is monadic, see firstJustM.
firstJust id [Nothing,Just 3] == Just 3 firstJust id [Nothing,Nothing] == Nothing
first3 :: (a -> a') -> (a, b, c) -> (a', b, c)extra Data.Tuple.Extra Update the first component of a triple.
first3 succ (1,1,1) == (2,1,1)
firstM :: Functor m => (a -> m a') -> (a, b) -> m (a', b)extra Data.Tuple.Extra Update the first component of a pair.
firstM (\x -> [x-1, x+1]) (1,"test") == [(0,"test"),(2,"test")]
first3 :: (a -> a') -> (a, b, c) -> (a', b, c)extra Extra Update the first component of a triple.
first3 succ (1,1,1) == (2,1,1)
firstJust :: (a -> Maybe b) -> [a] -> Maybe bextra Extra Find the first element of a list for which the operation returns Just, along with the result of the operation. Like find but useful where the function also computes some expensive information that can be reused. Particular useful when the function is monadic, see firstJustM.
firstJust id [Nothing,Just 3] == Just 3 firstJust id [Nothing,Nothing] == Nothing
firstJustM :: Monad m => (a -> m (Maybe b)) -> [a] -> m (Maybe b)extra Extra Like findM, but also allows you to compute some additional information in the predicate.