{-# LANGUAGE UndecidableInstances #-} module Prologue ( module X , eitherM , maybeM , maybeLast , fromMaybeLast ) where import Debug.Trace as X (traceShowM, traceM) import Data.Bifunctor.Join as X import Data.Bits as X import Data.ByteString as X (ByteString) import Data.Coerce as X import Data.Int as X (Int8, Int16, Int32, Int64) import Data.Either as X (fromLeft, fromRight) import Data.IntMap as X (IntMap) import Data.IntSet as X (IntSet) import Data.Ix as X (Ix (..)) import Data.List.NonEmpty as X (NonEmpty (..), nonEmpty, some1) import Data.Map as X (Map) import Data.Maybe as X import Data.Sequence as X (Seq) import Data.Semilattice.Lower as X (Lower(..)) import Data.Set as X (Set) import Data.Sum as X (Sum, Element, Elements, (:<), (:<:), Apply (..), inject) import Data.Text as X (Text) import Data.Word as X (Word8, Word16, Word32, Word64) import Control.Exception as X hiding (Handler (..), assert, evaluate, throw, throwIO, throwTo) -- Typeclasses import Control.Applicative as X import Control.Arrow as X ((&&&), (***)) import Control.Effect.NonDet as X (foldMapA) import Control.Monad as X hiding (fail, return) import Control.Monad.Fail as X (MonadFail (..)) import Control.Monad.IO.Class as X (MonadIO (..)) import Data.Algebra as X import Data.Bifoldable as X import Data.Bifunctor as X (Bifunctor (..)) import Data.Bitraversable as X import Data.Foldable as X hiding (product, sum) import Data.Function as X (fix, on, (&)) import Data.Functor as X (void, ($>)) import Data.Functor.Classes as X import Data.Functor.Classes.Generic as X import Data.Functor.Foldable as X (Base, Corecursive (..), Recursive (..)) import Data.Hashable as X (Hashable, hash, hashUsing, hashWithSalt) import Data.Hashable.Lifted as X (Hashable1(..), hashWithSalt1) import Data.Monoid as X (First (..), Last (..), Monoid (..)) import Data.Monoid.Generic as X import Data.Proxy as X (Proxy (..)) import Data.Semigroup as X (Semigroup (..)) import Data.Traversable as X import Data.Typeable as X (Typeable) -- Generics import GHC.Generics as X (Generic, Generic1) import GHC.Stack as X maybeLast :: Foldable t => b -> (a -> b) -> t a -> b maybeLast b f = maybe b f . getLast . foldMap (Last . Just) fromMaybeLast :: Foldable t => a -> t a -> a fromMaybeLast b = fromMaybe b . getLast . foldMap (Last . Just) -- | Extract the 'Just' of a 'Maybe' in an 'Applicative' context or, given 'Nothing', run the provided action. maybeM :: Applicative f => f a -> Maybe a -> f a maybeM f = maybe f pure {-# INLINE maybeM #-} -- Promote a function to either-applicatives. eitherM :: Applicative f => (a -> f b) -> Either a b -> f b eitherM f = either f pure {-# INLINE eitherM #-}