Explicit exports and add additional transformers.

postlude.cabal

@@ -18,5 +18,6 @@ library
   hs-source-dirs:      src
   default-language:    Haskell2010
   build-depends:       base >= 4.7 && < 5,
+                       either == 4.4.1.1,
                        mtl == 2.2.1,
                        transformers == 0.5.5.0

src/Postlude.hs

@@ -1,56 +1,89 @@
 {-# LANGUAGE NoImplicitPrelude #-}
 
+-- The following maps all imports into a single module alias for easy exporting.
+-- In all cases, we choose to explicitly list all exports (and avoid the use of
+-- the .. syntactic construct) to make it clear what is being included when
+-- importing the Postlude module.
+--
+-- It is generally expected one will add the -XNoImplicitPrelude pragma to the
+-- file Postlude is being used in, and to import Postlude without any
+-- qualification.
 module Postlude (module X) where
 
 import Control.Applicative as X
-  ( Applicative (..)
+  ( Applicative, (*>), (<*), (<*>), pure
   , (<$>)
-  , pure
   )
 
 import Control.Arrow as X
-  ( Arrow (..)
+  ( Arrow, (&&&), (***), arr, first, second
-  , ArrowChoice (..)
+  , ArrowChoice, (+++), (|||), left, right
-  , ArrowLoop (..)
+  , ArrowLoop, loop
-  , ArrowMonad (..)
+  , ArrowMonad
-  , ArrowPlus (..)
+  , ArrowPlus, (<+>)
-  , ArrowZero (..)
+  , ArrowZero, zeroArrow
   , (<<<)
   , (>>>)
   , returnA
   )
 
 import Control.Monad as X
-  ( Monad (..)
+  ( Monad, (>>=), (>>), return, fail
-  , MonadPlus (..)
+  , MonadPlus, mplus, mzero
-  , filterM
   , guard
   )
 
 import Control.Monad.Reader as X
-  ( MonadReader (..)
+  ( MonadReader, ask, local, reader
+  , Reader
+  , runReader
+  )
+
+import Control.Monad.State as X
+  ( State
+  )
+
+import Control.Monad.Writer as X
+  ( Writer
   )
 
 import Control.Monad.Trans as X
-  ( MonadIO (..)
+  ( MonadIO, liftIO
   , lift
   )
 
+import Control.Monad.Trans.Either as X
+  ( EitherT, runEitherT
+  )
+
 import Control.Monad.Trans.Except as X
-  ( ExceptT (..)
+  -- Note runExceptT is not actually a type declaration within the ExceptT
-  , runExceptT
+  -- newtype but writing as follows for consistency's sake.
+  ( ExceptT, runExceptT
   )
 
 import Control.Monad.Trans.Maybe as X
-  ( MaybeT (..)
+  ( MaybeT, runMaybeT
   )
 
 import Control.Monad.Trans.Reader as X
-  ( ReaderT (..)
+  ( ReaderT, runReaderT
+  )
+
+-- Note there also exists a strict interpretation but we default to the lazy
+-- implementation.
+import Control.Monad.Trans.State as X
+  ( StateT, runStateT
+  )
+
+-- Note there also exists a strict interpretation but we default to the lazy
+-- implementation.
+import Control.Monad.Trans.Writer as X
+  ( WriterT, runWriterT
   )
 
 import Data.Bool as X
-  ( Bool (..)
+  ( Bool, Bool(False), Bool(True)
   , (&&)
   , (||)
   , not
@@ -58,15 +91,15 @@ import Data.Bool as X
   )
 
 import Data.Char as X
-  ( Char (..)
+  ( Char
   )
 
 import Data.Either as X
-  ( Either (..)
+  ( Either, Either(Left), Either(Right)
   )
 
 import Data.Eq as X
-  ( Eq (..)
+  ( Eq, (/=), (==)
   )
 
 import Data.Function as X
@@ -81,14 +114,14 @@ import Data.Function as X
   )
 
 import Data.Functor as X
-  ( Functor (..)
+  ( Functor, (<$), fmap
   , ($>)
   , (<$>)
   , void
   )
 
 import Data.Functor.Identity as X
-  ( Identity (..)
+  ( Identity, runIdentity
   )
 
 import Data.Int as X
@@ -114,16 +147,16 @@ import Data.List as X
   )
 
 import Data.Maybe as X
-  ( Maybe (..)
+  ( Maybe, Maybe(Just), Maybe(Nothing)
   )
 
 import Data.Monoid as X
-  ( Monoid (..)
+  ( Monoid, mappend, mconcat, mempty
   )
 
 import Data.Ord as X
-  ( Ord (..)
+  ( Ord, (<), (<=), (>), (>=), compare, max, min
-  , Ordering (..)
+  , Ordering, Ordering(EQ), Ordering(GT), Ordering(LT)
   )
 
 import Data.String as X
@@ -131,12 +164,20 @@ import Data.String as X
   )
 
 import Data.Traversable as X
-  ( Traversable (..)
+  ( Traversable, mapM, sequence, sequenceA, traverse
   )
 
 import GHC.Enum as X
-  ( Bounded (..)
+  ( Bounded, maxBound, minBound
-  , Enum (..)
+  , Enum
+  ,   enumFrom
+  ,   enumFromThen
+  ,   enumFromThenTo
+  ,   enumFromTo
+  ,   fromEnum
+  ,   pred
+  ,   succ
+  ,   toEnum
   )
 
 import GHC.Err as X
@@ -144,26 +185,62 @@ import GHC.Err as X
   )
 
 import GHC.Float as X
-  ( Double (..)
+  ( Double
-  , Float (..)
+  , Float
-  , Floating (..)
+  , Floating
-  , RealFloat (..)
+  ,   (**)
+  ,   acos
+  ,   acosh
+  ,   asin
+  ,   asinh
+  ,   atan
+  ,   atanh
+  ,   cos
+  ,   cosh
+  ,   exp
+  ,   expm1
+  ,   log
+  ,   log1mexp
+  ,   log1p
+  ,   log1pexp
+  ,   logBase
+  ,   pi
+  ,   sin
+  ,   sinh
+  ,   sqrt
+  ,   tan
+  ,   tanh
+  , RealFloat
+  ,   atan2
+  ,   decodeFloat
+  ,   encodeFloat
+  ,   exponent
+  ,   floatDigits
+  ,   floatRadix
+  ,   floatRange
+  ,   isDenormalized
+  ,   isIEEE
+  ,   isInfinite
+  ,   isNaN
+  ,   isNegativeZero
+  ,   scaleFloat
+  ,   significand
   )
 
 import GHC.Num as X
-  ( Num (..)
+  ( Num, (*), (+), (-), abs, fromInteger, negate, signum
   , Integer
   )
 
 import GHC.Real as X
-  ( Fractional (..)
+  ( Fractional, (/), fromRational, recip
-  , Integral (..)
+  , Integral, div, divMod, mod, quot, quotRem, rem, toInteger
-  , Ratio (..)
+  , Ratio
   , Rational
   )
 
 import GHC.Show as X
-  ( Show (..)
+  ( Show, show, showList, showsPrec
   )
 
 import System.Environment as X
@@ -174,7 +251,11 @@ import System.IO as X
   ( FilePath
   , Handle
   , IO
-  , IOMode (..)
+  , IOMode
+  ,   IOMode(AppendMode)
+  ,   IOMode(ReadMode)
+  ,   IOMode(ReadWriteMode)
+  ,   IOMode(WriteMode)
   , openFile
   , print
   , stderr