{-# LANGUAGE CPP #-}
-- |
-- This module reexports most of the definitions from the \"base\" package,
-- which are meant to be imported unqualified.
--
-- For details check out the source.
module Lazy.Prelude
(
  module Exports,
  -- * Reimplementations of functions presented in versions of \"base\" newer than 4.6
  -- ** Data.Bool
  bool,
  -- ** Data.Function
  (&),
  -- ** Data.Functor
  ($>),
  -- ** Data.List
  isSubsequenceOf,
  sortOn,
  uncons,
  -- ** Debug.Trace
  traceShowId,
  traceM,
  traceShowM,
)
where

-- Reexports
-------------------------

import Control.Applicative as Exports
import Control.Arrow as Exports hiding (first, second)
import Control.Category as Exports
import Control.Concurrent as Exports
import Control.Comonad as Exports hiding (($>))
import Control.Exception as Exports
import Control.Monad as Exports hiding (mapM_, sequence_, forM_, msum, mapM, sequence, forM)
import Control.Monad.Fix as Exports hiding (fix)
import Control.Monad.ST as Exports
import Data.Bits as Exports
import Data.Bool as Exports hiding (bool)
import Data.Char as Exports
import Data.Complex as Exports
import Data.Data as Exports
import Data.Dynamic as Exports
import Data.Either as Exports
import Data.Fixed as Exports
import Data.Foldable as Exports
import Data.Functor as Exports hiding (($>))
import Data.Function as Exports hiding ((.), id, (&))
import Data.Int as Exports
import Data.IORef as Exports
import Data.Ix as Exports
import Data.List as Exports hiding (sortOn, isSubsequenceOf, uncons, concat, foldr, foldl1, maximum, minimum, product, sum, all, and, any, concatMap, elem, foldl, foldr1, notElem, or, find, maximumBy, minimumBy, mapAccumL, mapAccumR, foldl')
import Data.Maybe as Exports
import Data.Monoid as Exports
import Data.Ord as Exports
import Data.Ratio as Exports
import Data.STRef as Exports
import Data.String as Exports
import Data.Traversable as Exports
import Data.Tuple as Exports
import Data.Unique as Exports
import Data.Version as Exports
import Data.Word as Exports
import Debug.Trace as Exports hiding (traceShowId, traceM, traceShowM)
import Foreign.Storable as Exports
import Foreign.Ptr as Exports
import Foreign.ForeignPtr as Exports
import Foreign.StablePtr as Exports
import GHC.Conc as Exports hiding (withMVar, threadWaitWriteSTM, threadWaitWrite, threadWaitReadSTM, threadWaitRead)
import GHC.Exts as Exports (lazy, inline, sortWith, groupWith)
import GHC.Generics as Exports (Generic)
import GHC.IO.Exception as Exports
import Numeric as Exports
import Prelude as Exports hiding (concat, foldr, mapM_, sequence_, foldl1, maximum, minimum, product, sum, all, and, any, concatMap, elem, foldl, foldr1, notElem, or, mapM, sequence, id, (.))
import System.Environment as Exports
import System.Exit as Exports
import System.IO as Exports (Handle, hClose)
import System.IO.Error as Exports
import System.IO.Unsafe as Exports
import System.Mem as Exports
import System.Mem.StableName as Exports
import System.Timeout as Exports
import Text.ParserCombinators.ReadP as Exports (ReadP, ReadS, readP_to_S, readS_to_P)
import Text.ParserCombinators.ReadPrec as Exports (ReadPrec, readPrec_to_P, readP_to_Prec, readPrec_to_S, readS_to_Prec)
import Text.Printf as Exports (printf, hPrintf)
import Text.Read as Exports (Read(..), readMaybe, readEither)
import Unsafe.Coerce as Exports

-- Conditional imports for newer bases
#if MIN_VERSION_base(4,7,0)
import Data.Coerce as Exports
import Data.Proxy as Exports
#endif
#if MIN_VERSION_base(4,8,0)
import Data.Bifunctor as Exports
import Data.Functor.Identity as Exports
import Data.Void as Exports
import Numeric.Natural as Exports
#endif
#if MIN_VERSION_base(4,9,0)
import Control.Monad.Fail as Exports (MonadFail)
import Control.Monad.IO.Class as Exports
import Data.Functor.Classes as Exports
import Data.Functor.Compose as Exports
import Data.List.NonEmpty as Exports (NonEmpty(..))
import Data.Semigroup as Exports hiding ((<>), First(..), Last(..))
#endif

-- Conditional imports for reimplementations
#if MIN_VERSION_base(4,7,0)
import Data.Bool (bool)
import Debug.Trace (traceShowId, traceM, traceShowM)
import Data.Functor (($>))
#endif
#if MIN_VERSION_base(4,8,0)
import Data.Function ((&))
import Data.List (isSubsequenceOf, sortOn, uncons)
#endif


---------------------------------
-- Reimplementations for base-4.7
---------------------------------

#if !MIN_VERSION_base(4,7,0)

-- | Case analysis for the 'Bool' type.
-- @bool a b p@ evaluates to @a@ when @p@ is @False@, and evaluates to @b@
-- when @p@ is @True@.
bool :: a -> a -> Bool -> a
bool f t b = if b then t else f

{-|
Like 'traceShow' but returns the shown value instead of a third value.
-}
traceShowId :: (Show a) => a -> a
traceShowId a = trace (show a) a

{-|
Like 'trace' but returning unit in an arbitrary monad. Allows for convenient
use in do-notation. Note that the application of 'trace' is not an action in the
monad, as 'traceIO' is in the 'IO' monad.

> ... = do
>   x <- ...
>   traceM $ "x: " ++ show x
>   y <- ...
>   traceM $ "y: " ++ show y
-}
traceM :: (Monad m) => String -> m ()
traceM string = trace string $ return ()

{-|
Like 'traceM', but uses 'show' on the argument to convert it to a 'String'.

> ... = do
>   x <- ...
>   traceShowM $ x
>   y <- ...
>   traceShowM $ x + y
-}
traceShowM :: (Show a, Monad m) => a -> m ()
traceShowM = traceM . show

infixl 4 $>

-- | Flipped version of '<$'.
($>) :: Functor f => f a -> b -> f b
($>) = flip (<$)

#endif

---------------------------------
-- Reimplementations for base-4.8
---------------------------------

#if !MIN_VERSION_base(4,8,0)

infixl 1 &

-- | '&' is a reverse application operator.  This provides notational
-- convenience.  Its precedence is one higher than that of the forward
-- application operator '$', which allows '&' to be nested in '$'.
(&) :: a -> (a -> b) -> b
x & f = f x

-- | The 'isSubsequenceOf' function takes two lists and returns 'True' if the
-- first list is a subsequence of the second list.
--
-- @'isSubsequenceOf' x y@ is equivalent to @'elem' x ('subsequences' y)@.
--
-- ==== __Examples__
--
-- >>> isSubsequenceOf "GHC" "The Glorious Haskell Compiler"
-- True
-- >>> isSubsequenceOf ['a','d'..'z'] ['a'..'z']
-- True
-- >>> isSubsequenceOf [1..10] [10,9..0]
-- False
isSubsequenceOf :: (Eq a) => [a] -> [a] -> Bool
isSubsequenceOf []    _                    = True
isSubsequenceOf _     []                   = False
isSubsequenceOf a@(x:a') (y:b) | x == y    = isSubsequenceOf a' b
                               | otherwise = isSubsequenceOf a b

-- | Decompose a list into its head and tail. If the list is empty,
-- returns 'Nothing'. If the list is non-empty, returns @'Just' (x, xs)@,
-- where @x@ is the head of the list and @xs@ its tail.
uncons        :: [a] -> Maybe (a, [a])
uncons []     = Nothing
uncons (x:xs) = Just (x, xs)

-- | Sort a list by comparing the results of a key function applied to each
-- element.  @sortOn f@ is equivalent to @sortBy . comparing f@, but has the
-- performance advantage of only evaluating @f@ once for each element in the
-- input list.  This is called the decorate-sort-undecorate paradigm, or
-- Schwartzian transform.
sortOn :: Ord b => (a -> b) -> [a] -> [a]
sortOn f =
  map snd . sortBy (comparing fst) . map (\x -> let y = f x in y `seq` (y, x))

#endif
