pragmatic-show-0.1.2.0: Text/Show/Pragmatic.hs
-- |
-- Module : Text.Show.Pragmatic
-- Copyright : (c) Justus Sagemüller 2017
-- License : GPL v3
--
-- Maintainer : (@) jsagemue $ uni-koeln.de
-- Stability : experimental
-- Portability : portable
--
{-# LANGUAGE CPP #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE UndecidableInstances #-}
module Text.Show.Pragmatic (
-- * Replacement for the standard class
Show(..), print
-- * Utility (unstable)
, ltdPrecShowsPrec
, showsPrecWithSharedPrecision
, ShowMagnitudeRangeLimited(..)
) where
import Prelude hiding (Show(..), shows, print)
import qualified Prelude
import Data.Foldable (toList)
import Data.List (intersperse, minimumBy)
import Data.Ord (comparing)
import Data.Int (Int8, Int16, Int32, Int64)
import Data.Word (Word8, Word16, Word32, Word64)
import Data.Ratio
import Data.Complex (Complex((:+)), magnitude)
#if MIN_VERSION_base(4,8,0)
import Numeric.Natural (Natural)
#endif
#if MIN_VERSION_base(4,10,0)
import Type.Reflection (TyCon, SomeTypeRep, Module)
#endif
#if MIN_VERSION_base(4,9,0)
import GHC.Stack (SrcLoc, CallStack)
#endif
#if MIN_VERSION_base(3,0,0)
import Control.Exception.Base ( SomeException, ArithException, ErrorCall, IOException
, MaskingState
, ArrayException, AsyncException
#if MIN_VERSION_base(4,7,0)
, SomeAsyncException
#endif
, AssertionFailed
#if MIN_VERSION_base(4,10,0)
, CompactionFailed
#endif
#if MIN_VERSION_base(4,7,1)
, AllocationLimitExceeded
#endif
, Deadlock, BlockedIndefinitelyOnSTM
, BlockedIndefinitelyOnMVar
, NestedAtomically, NonTermination
#if MIN_VERSION_base(4,9,0)
, TypeError
#endif
, NoMethodError
, RecUpdError, RecConError, RecSelError, PatternMatchFail
)
#endif
import Data.Char (GeneralCategory)
import Text.Read.Lex (Number, Lexeme)
#if MIN_VERSION_base(4,7,0)
import GHC.Fingerprint.Type (Fingerprint)
#endif
import System.IO (IOMode)
import System.IO.Error (IOErrorType)
import System.Exit (ExitCode)
import Foreign.Ptr (IntPtr, WordPtr)
import Foreign.C.Types ( CUIntMax, CIntMax, CUIntPtr, CIntPtr
, CSUSeconds, CUSeconds, CTime, CClock
, CSigAtomic, CWchar, CSize, CPtrdiff
, CDouble, CFloat
#if MIN_VERSION_base(4,10,0)
, CBool
#endif
, CULLong, CLLong, CULong, CLong, CUInt, CInt, CUShort, CShort
, CUChar, CSChar, CChar
)
#if MIN_VERSION_base(4,10,0)
import GHC.TypeNats (SomeNat)
import GHC.TypeLits (SomeSymbol)
#endif
#if MIN_VERSION_base(4,9,0)
import GHC.Generics ( DecidedStrictness, SourceStrictness, SourceUnpackedness
, Associativity, Fixity )
#endif
import Data.Monoid (Any, All)
#if MIN_VERSION_base(4,4,0)
import GHC.IO.Encoding.Types (CodingProgress, TextEncoding)
import GHC.IO.Encoding.Failure (CodingFailureMode)
#endif
import GHC.IO.Device (SeekMode)
import GHC.IO.Handle (NewlineMode, Newline, BufferMode, Handle, HandlePosn)
#if MIN_VERSION_base(4,10,0)
import GHC.IO.Handle.Lock (FileLockingNotSupported)
#endif
#if MIN_VERSION_base(4,9,0)
import GHC.StaticPtr (StaticPtrInfo)
#endif
import System.Posix.Types ( Fd
#if MIN_VERSION_base(4,10,0)
, CTimer, CKey, CId, CFsFilCnt, CFsBlkCnt, CClockId
, CBlkCnt, CBlkSize
#endif
, CRLim, CTcflag, CSpeed, CCc, CUid
, CNlink, CGid, CSsize, CPid, COff, CMode, CIno, CDev )
#if MIN_VERSION_base(4,8,1)
import GHC.Event (Lifetime, Event, FdKey)
#endif
#if MIN_VERSION_base(2,1,0)
import Data.Dynamic (Dynamic)
#endif
import GHC.Conc (ThreadStatus, BlockReason)
import Control.Concurrent (ThreadId)
#if MIN_VERSION_base(4,8,0)
import Data.Version (Version)
#endif
#if MIN_VERSION_base(4,5,0)
import Data.Version (Version)
#endif
#if MIN_VERSION_base(4,10,0)
import GHC.Stats (RTSStats)
#endif
#if MIN_VERSION_base(4,9,0)
import GHC.RTS.Flags ( RTSFlags
#if MIN_VERSION_base(4,10,0)
, ParFlags
#endif
, TickyFlags, TraceFlags, DoTrace, ProfFlags
, DoHeapProfile, CCFlags, DoCostCentres, DebugFlags, MiscFlags
, ConcFlags, GCFlags, GiveGCStats )
#endif
import Data.Data ( Fixity, ConstrRep, DataRep
#if MIN_VERSION_base(4,0,0)
, Constr
#endif
, DataType )
#if MIN_VERSION_base(4,8,0)
import Data.Void
#endif
import qualified Data.Set as Set
import qualified Data.IntSet as ℤSet
import qualified Data.Map as Map
import qualified Data.IntMap as ℤMap
import qualified Data.Sequence as Seq
import qualified Data.Tree as Tree
-- | A drop-in replacement for 'Prelude.Show'. The behaviour is mostly the same:
-- the result of 'show' should be valid Haskell code, and 'read'ing back such a
-- value should give the original value – but, unlike in 'Prelude.Show', we don't
-- require this in an /exact/ sense, i.e. @'read' ('show' x) == x@ is not necessarily
-- fulfilled.
--
-- Notably for floating-point values, we allow a slight deviation if
-- it considerably shortens the shown representation: for example,
-- @0.90000004 :: Float@, which can easily come up as
-- the result of a computation which should in principle be exactly @0.9@, is shown
-- as @0.9@ instead. We do however /not/ commit to any particular fixed precision;
-- it depends on the type and the order of magnitude which amount of rounding is
-- appropriate. See <https://github.com/leftaroundabout/pragmatic-show/blob/master/test/tasty/test.hs the test suite> for some examples.
class Show a where
{-# MINIMAL showsPrec | show #-}
showsPrec :: Int -> a -> ShowS
showsPrec _ x = (show x++)
show :: a -> String
show = (`shows`"")
showList :: [a] -> ShowS
showList = defaultShowList
defaultShowList :: Show a => [a] -> ShowS
defaultShowList [] = ("[]"++)
defaultShowList (x:xs) = ('[':) . shows x . flip (foldr (\y -> (',':) . shows y)) xs . (']':)
shows :: Show a => a -> ShowS
shows = showsPrec 0
#define StdShow(A) \
instance Show (A) where { \
show = Prelude.show; \
showsPrec = Prelude.showsPrec; \
showList = Prelude.showList }
StdShow (Bool)
StdShow (Int)
StdShow (Int8)
StdShow (Int16)
StdShow (Int32)
StdShow (Int64)
StdShow (Integer)
#if MIN_VERSION_base(4,8,0)
StdShow (Natural)
#endif
StdShow (Ordering)
StdShow (Word)
StdShow (Word8)
StdShow (Word16)
StdShow (Word32)
StdShow (Word64)
#if MIN_VERSION_base(4,9,0)
StdShow (CallStack)
#endif
#if MIN_VERSION_base(4,10,0)
StdShow (SomeTypeRep)
#endif
StdShow (())
#if MIN_VERSION_base(4,10,0)
StdShow (TyCon)
StdShow (Module)
#endif
#if MIN_VERSION_base(4,9,0)
StdShow (SrcLoc)
#endif
#if MIN_VERSION_base(3,0,0)
StdShow (SomeException)
#endif
StdShow (GeneralCategory)
StdShow (Number)
StdShow (Lexeme)
#if MIN_VERSION_base(4,7,0)
StdShow (Fingerprint)
#endif
StdShow (IOMode)
StdShow (IntPtr)
StdShow (WordPtr)
StdShow (CUIntMax)
StdShow (CIntMax)
StdShow (CUIntPtr)
StdShow (CIntPtr)
StdShow (CSUSeconds)
StdShow (CUSeconds)
StdShow (CTime)
StdShow (CClock)
StdShow (CSigAtomic)
StdShow (CWchar)
StdShow (CSize)
StdShow (CPtrdiff)
#if MIN_VERSION_base(4,10,0)
StdShow (CBool)
#endif
StdShow (CULLong)
StdShow (CLLong)
StdShow (CULong)
StdShow (CLong)
StdShow (CUInt)
StdShow (CInt)
StdShow (CUShort)
StdShow (CShort)
StdShow (CUChar)
StdShow (CSChar)
StdShow (CChar)
#if MIN_VERSION_base(4,10,0)
StdShow (SomeNat)
StdShow (SomeSymbol)
#endif
#if MIN_VERSION_base(4,9,0)
StdShow (DecidedStrictness)
StdShow (SourceStrictness)
StdShow (SourceUnpackedness)
StdShow (Associativity)
StdShow (GHC.Generics.Fixity)
#endif
StdShow (Any)
StdShow (All)
#if MIN_VERSION_base(4,0,0)
StdShow (ArithException)
StdShow (ErrorCall)
#endif
#if MIN_VERSION_base(4,1,0)
StdShow (IOException)
#endif
StdShow (MaskingState)
#if MIN_VERSION_base(4,4,0)
StdShow (CodingProgress)
#endif
#if MIN_VERSION_base(4,3,0)
StdShow (TextEncoding)
#endif
StdShow (SeekMode)
StdShow (NewlineMode)
StdShow (Newline)
StdShow (BufferMode)
#if MIN_VERSION_base(4,1,0)
StdShow (Handle)
StdShow (IOErrorType)
#endif
StdShow (ExitCode)
#if MIN_VERSION_base(4,1,0)
StdShow (ArrayException)
StdShow (AsyncException)
#endif
#if MIN_VERSION_base(4,7,0)
StdShow (SomeAsyncException)
#endif
#if MIN_VERSION_base(4,1,0)
StdShow (AssertionFailed)
#endif
#if MIN_VERSION_base(4,10,0)
StdShow (CompactionFailed)
#endif
#if MIN_VERSION_base(4,7,1)
StdShow (AllocationLimitExceeded)
#endif
#if MIN_VERSION_base(4,1,0)
StdShow (Deadlock)
StdShow (BlockedIndefinitelyOnSTM)
StdShow (BlockedIndefinitelyOnMVar)
StdShow (CodingFailureMode)
#endif
StdShow (Fd)
#if MIN_VERSION_base(4,10,0)
StdShow (CTimer)
StdShow (CKey)
StdShow (CId)
StdShow (CFsFilCnt)
StdShow (CFsBlkCnt)
StdShow (CClockId)
StdShow (CBlkCnt)
StdShow (CBlkSize)
#endif
StdShow (CRLim)
StdShow (CTcflag)
StdShow (CSpeed)
StdShow (CCc)
StdShow (CUid)
StdShow (CNlink)
StdShow (CGid)
StdShow (CSsize)
StdShow (CPid)
StdShow (COff)
StdShow (CMode)
StdShow (CIno)
StdShow (CDev)
#if MIN_VERSION_base(4,8,1)
StdShow (Lifetime)
StdShow (Event)
#endif
#if MIN_VERSION_base(2,1,0)
StdShow (Dynamic)
#endif
StdShow (ThreadStatus)
StdShow (BlockReason)
#if MIN_VERSION_base(4,2,0)
StdShow (ThreadId)
#endif
#if MIN_VERSION_base(4,0,0)
StdShow (NestedAtomically)
StdShow (NonTermination)
#endif
#if MIN_VERSION_base(4,9,0)
StdShow (TypeError)
#endif
#if MIN_VERSION_base(4,0,0)
StdShow (NoMethodError)
StdShow (RecUpdError)
StdShow (RecConError)
StdShow (RecSelError)
StdShow (PatternMatchFail)
#endif
StdShow (FdKey)
#if MIN_VERSION_base(4,10,0)
StdShow (FileLockingNotSupported)
#endif
#if MIN_VERSION_base(4,1,0)
StdShow (HandlePosn)
#endif
#if MIN_VERSION_base(4,8,0)
StdShow (Version)
#endif
#if MIN_VERSION_base(4,10,0)
StdShow (RTSStats)
StdShow (ParFlags)
#endif
#if MIN_VERSION_base(4,9,0)
StdShow (RTSFlags)
StdShow (TickyFlags)
StdShow (TraceFlags)
StdShow (DoTrace)
StdShow (ProfFlags)
StdShow (DoHeapProfile)
StdShow (CCFlags)
StdShow (DoCostCentres)
StdShow (DebugFlags)
StdShow (MiscFlags)
StdShow (ConcFlags)
StdShow (GCFlags)
StdShow (GiveGCStats)
#endif
StdShow (Data.Data.Fixity)
StdShow (ConstrRep)
StdShow (DataRep)
#if MIN_VERSION_base(4,0,0)
StdShow (Constr)
#endif
StdShow (DataType)
#if MIN_VERSION_base(4,9,0)
StdShow (StaticPtrInfo)
#endif
#if MIN_VERSION_base(4,8,0)
StdShow (Void)
#endif
instance Show Char where
show c | c>'\31', c/='\'', c/='\\'
= '\'':c:"'"
| otherwise = Prelude.show c
showList cs = ('"':) . flip (foldr showc) cs . ('"':)
where showc '"' = ("\\\""++)
showc '\\' = ("\\\\"++)
showc '\SO' = ("\\SO\\&"++) -- prevent problem with "\SO\&H"≈[14,72] getting
-- shown as "\SOH"≈[2]. (Thanks, QuickCheck!)
showc c | c>'\31' = (c:)
| otherwise = case show c of
('\'':q) -> case break (=='\'') q of
(r,"'") -> (r++)
class Show a => ShowMagnitudeRangeLimited a where
showsPrecMagnitudeRangeLimited :: Int -> Int -> a -> ShowS
instance Show Float where
showsPrec = ltdPrecShowsPrec 7
showList = ltdPrecShowList id 7
instance ShowMagnitudeRangeLimited Float where
showsPrecMagnitudeRangeLimited = ltdPrecShowsPrec
instance Show Double where
showsPrec = ltdPrecShowsPrec 10
showList = ltdPrecShowList id 10
instance ShowMagnitudeRangeLimited Double where
showsPrecMagnitudeRangeLimited = ltdPrecShowsPrec
instance Show CFloat where
showsPrec = ltdPrecShowsPrec 5
showList = ltdPrecShowList id 5
instance ShowMagnitudeRangeLimited CFloat where
showsPrecMagnitudeRangeLimited = ltdPrecShowsPrec
instance Show CDouble where
showsPrec = ltdPrecShowsPrec 10
showList = ltdPrecShowList id 10
instance ShowMagnitudeRangeLimited CDouble where
showsPrecMagnitudeRangeLimited = ltdPrecShowsPrec
ltdPrecShowList :: (ShowMagnitudeRangeLimited n, RealFloat sn)
=> (n -> sn) -> Int -> [n] -> ShowS
ltdPrecShowList realise precision vals
= ('[':) . flip (foldr id)
(intersperse (',':)
$ showsPrecWithSharedPrecision realise precision 0 vals)
. (']':)
showsPrecWithSharedPrecision :: (ShowMagnitudeRangeLimited n, RealFloat sn, Traversable list)
=> (n -> sn) -- ^ Magnitude-function. Should be a norm.
-> Int -- ^ Precision of the type, in significant decimals. This will
-- be used to trim the length of all entries to match the
-- expected numerical uncertainty of the biggest one.
-> Int -- ^ Precedence of the enclosing context in which the values
-- are to be shown.
-> list n -- ^ Values to show
-> list ShowS -- ^ Individual values' string representation.
showsPrecWithSharedPrecision realise precision p vals
= fmap (\val ->
let uMagn = usableMagnitude $ realise val
in showsPrecMagnitudeRangeLimited
(max 0 $ precision - floor (maxUMag - uMagn)) p val
) vals
where usableMagnitude n
| n<0 = usableMagnitude (-n)
| n==n, 2*n>n = logBase 10 n
| otherwise = -1/0
maxUMag = maximum $ usableMagnitude . realise <$> vals
-- | @'ltdPrecShowsPrec' prcn@ displays floating-point values with a precision
-- of at least @prcn@ digits. That does not mean it will necessarily display
-- that many digits, rather it tries to always choose the shortest representation
-- with the required precision.
ltdPrecShowsPrec :: (RealFloat n) => Int -> Int -> n -> ShowS
ltdPrecShowsPrec precision p n cont
= minimumBy (comparing length)
[ postProc $ ltdPrecShowsPrecDecimal precision p' (preProc n) ""
| (preProc, p', postProc)
<- [ (id, p, id) ]
++[ ( (/μ)
, 7, \s -> case s of
"1" -> sμ ""
"(-1)"-> showParen (p>=6) (('-':) . sμ) ""
_ -> showParen (p>7) ((s++) . ('*':) . sμ) ""
)
| (μ,sμ) <- (pi, ("pi"++))
:[ (pi / fromIntegral m, ("pi/"++) . shows m)
| m<-[2,3,4 :: Int] ]
++[ (sqrt $ fromIntegral n, ("sqrt "++) . shows n)
| n<-[2,3,5 :: Int] ]
++[ ( sqrt (fromIntegral n)/fromIntegral m
, ("sqrt "++) . shows n . ('/':) . shows m)
| n<-[2,3 :: Int]
, m<-[2,3 :: Int] ]
]
++[ ( (*fromIntegral n)
, 7, \s -> showParen (p>7) ((s++) . ('/':) . shows n) "" )
| n<-[3,7,9 :: Int] ]
] ++ cont
ltdPrecShowsPrecDecimal :: (RealFloat n) => Int -> Int -> n -> ShowS
ltdPrecShowsPrecDecimal _ _ 0 = ("0"++)
ltdPrecShowsPrecDecimal precision p n
| not (n==n) = ("NaN"++)
| n<0 = showParen (p>5)
$ ('-':) . ltdPrecShowsPrecDecimal precision 0 (negate n)
| n==n*2 = ("Infinity"++)
| e₁₀<7 && lrDigs <= e₁₀
= (rDigits++) . (replicate (e₁₀-lrDigs) '0' ++)
| e₁₀>0 && e₁₀<3
= (take e₁₀ rDigits++) . ('.':) . (drop e₁₀ rDigits++)
| e₁₀> -2 && e₁₀<=0
= ("0."++) . (replicate (negate e₁₀) '0'++) . (rDigits++)
| [hd] <- rDigits
= (hd:) . ("e"++) . shows (e₁₀-1)
| (hd:qd@(_:_)) <- rDigits
= (hd:) . ('.':) . (qd++) . ("e"++) . shows (e₁₀-1)
where (e₁₀,m₁₀Approx) = correctPrecision . ceiling $ logBase 10 n
where correctPrecision e
= case show (round $ n * 10^^(precision+2 - e) :: Int) of
digits | length digits <= precision+2 -> (e,digits)
| otherwise -> correctPrecision $ e+1
(rApprZeroes, rDigits') = break (>'0') . reverse $ m₁₀Approx
rDigits = reverse rDigits'
lrDigs = length rDigits
instance (Show a) => Show [a] where
showsPrec _ = showList
instance (Show a, Ord a) => Show (Seq.Seq a) where
showsPrec _ = defaultShowList . toList
instance (Show a, Ord a) => Show (Set.Set a) where
showsPrec _ = defaultShowList . Set.toList
instance Show ℤSet.IntSet where
showsPrec _ = defaultShowList . ℤSet.toList
instance (Show a, Ord a, Show b) => Show (Map.Map a b) where
showsPrec _ = defaultShowList . Map.toList
instance (Show b) => Show (ℤMap.IntMap b) where
showsPrec _ = defaultShowList . ℤMap.toList
instance (Show a) => Show (Tree.Tree a) where
showsPrec p (Tree.Node a st) = showParen (p>9)
$ ("Node "++) . showsPrec 11 a . (' ':) . shows st
instance (Show a, Show b) => Show (a,b) where
showsPrec _ (a,b) = ('(':) . shows a . (',':) . shows b . (')':)
instance (Show a, Show b, Show c) => Show (a,b,c) where
showsPrec _ (a,b,c) = ('(':) . shows a . (',':) . shows b . (',':) . shows c . (')':)
instance (Show a, Show b, Show c, Show d) => Show (a,b,c,d) where
showsPrec _ (a,b,c,d) = ('(':)
. shows a . (',':) . shows b . (',':) . shows c . (',':) . shows d
. (')':)
instance (Integral i, Show i) => Show (Ratio i) where
showsPrec p n
| n<0 = showParen (p>5) $ ('-':) . showsPrec 6 (-n)
| denominator n == 1 = shows $ numerator n
| otherwise = showParen (p>6) $ shows (numerator n)
. ('/':) . shows (denominator n)
instance Show (Complex Double) where
showsPrec = ltdPrecShowsPrecComplex 10
showList = ltdPrecShowList magnitude 10
instance Show (Complex Float) where
showsPrec = ltdPrecShowsPrecComplex 7
showList = ltdPrecShowList magnitude 7
instance (RealFloat a, Show (Complex a), ShowMagnitudeRangeLimited a)
=> ShowMagnitudeRangeLimited (Complex a) where
showsPrecMagnitudeRangeLimited = ltdPrecShowsPrecComplex
ltdPrecShowsPrecComplex :: (RealFloat r, ShowMagnitudeRangeLimited r)
=> Int -> Int -> Complex r -> ShowS
ltdPrecShowsPrecComplex precision p (r:+i)
| abs r > abs i * 10^precision
= ltdPrecShowsPrec precision p r
| otherwise
= case ($"")<$>showsPrecWithSharedPrecision id precision 6 [r,i] of
[sr,"0"] -> showParen (p>7) $ (sr++)
[sr,si] -> showParen (p>6) $ (sr++) . (":+"++) . (si++)
-- | Drop-in for the standard screen-displaying function. This is useful as a GHCi
-- evaluation action; invoke with
-- @
-- $ ghci -interactive-print=Text.Show.Pragmatic.print
-- @
-- to get more concise output from the REPL.
print :: Show a => a -> IO ()
print = putStrLn . show