| Copyright | (c) The University of Glasgow 1992-2002 |
|---|---|
| License | see libraries/base/LICENSE |
| Maintainer | cvs-ghc@haskell.org |
| Stability | internal |
| Portability | non-portable (GHC Extensions) |
| Safe Haskell | Trustworthy |
| Language | Haskell2010 |
GHC.Show
Description
The Show class, and related operations.
Synopsis
- class Show a where
- type ShowS = String -> String
- shows :: Show a => a -> ShowS
- showChar :: Char -> ShowS
- showString :: String -> ShowS
- showMultiLineString :: String -> [String]
- showParen :: Bool -> ShowS -> ShowS
- showList__ :: (a -> ShowS) -> [a] -> ShowS
- showCommaSpace :: ShowS
- showSpace :: ShowS
- showLitChar :: Char -> ShowS
- showLitString :: String -> ShowS
- protectEsc :: (Char -> Bool) -> ShowS -> ShowS
- intToDigit :: Int -> Char
- showSignedInt :: Int -> Int -> ShowS
- appPrec :: Int
- appPrec1 :: Int
- asciiTab :: [String]
Documentation
Conversion of values to readable Strings.
Derived instances of Show have the following properties, which
are compatible with derived instances of Read:
- The result of
showis a syntactically correct Haskell expression containing only constants, given the fixity declarations in force at the point where the type is declared. It contains only the constructor names defined in the data type, parentheses, and spaces. When labelled constructor fields are used, braces, commas, field names, and equal signs are also used. - If the constructor is defined to be an infix operator, then
showsPrecwill produce infix applications of the constructor. - the representation will be enclosed in parentheses if the
precedence of the top-level constructor in
xis less thand(associativity is ignored). Thus, ifdis0then the result is never surrounded in parentheses; ifdis11it is always surrounded in parentheses, unless it is an atomic expression. - If the constructor is defined using record syntax, then
showwill produce the record-syntax form, with the fields given in the same order as the original declaration.
For example, given the declarations
infixr 5 :^: data Tree a = Leaf a | Tree a :^: Tree a
the derived instance of Show is equivalent to
instance (Show a) => Show (Tree a) where
showsPrec d (Leaf m) = showParen (d > app_prec) $
showString "Leaf " . showsPrec (app_prec+1) m
where app_prec = 10
showsPrec d (u :^: v) = showParen (d > up_prec) $
showsPrec (up_prec+1) u .
showString " :^: " .
showsPrec (up_prec+1) v
where up_prec = 5Note that right-associativity of :^: is ignored. For example,
show(Leaf 1 :^: Leaf 2 :^: Leaf 3)"Leaf 1 :^: (Leaf 2 :^: Leaf 3)".
Methods
Arguments
| :: Int | the operator precedence of the enclosing
context (a number from |
| -> a | the value to be converted to a |
| -> ShowS |
Convert a value to a readable String.
showsPrec should satisfy the law
showsPrec d x r ++ s == showsPrec d x (r ++ s)
Derived instances of Read and Show satisfy the following:
That is, readsPrec parses the string produced by
showsPrec, and delivers the value that showsPrec started with.
Instances
| Show Bool # | Since: base-2.1 |
| Show Char # | Since: base-2.1 |
| Show Double # | Since: base-2.1 |
| Show Float # | Since: base-2.1 |
| Show Int # | Since: base-2.1 |
| Show Int8 # | Since: base-2.1 |
| Show Int16 # | Since: base-2.1 |
| Show Int32 # | Since: base-2.1 |
| Show Int64 # | Since: base-2.1 |
| Show Integer # | Since: base-2.1 |
| Show Natural # | Since: base-4.8.0.0 |
| Show Ordering # | Since: base-2.1 |
| Show Word # | Since: base-2.1 |
| Show Word8 # | Since: base-2.1 |
| Show Word16 # | Since: base-2.1 |
| Show Word32 # | Since: base-2.1 |
| Show Word64 # | Since: base-2.1 |
| Show RuntimeRep # | Since: base-4.11.0.0 |
| Show VecCount # | Since: base-4.11.0.0 |
| Show VecElem # | Since: base-4.11.0.0 |
| Show CallStack # | Since: base-4.9.0.0 |
| Show SomeTypeRep # | Since: base-4.10.0.0 |
Defined in Data.Typeable.Internal | |
| Show () # | Since: base-2.1 |
| Show TyCon # | Since: base-2.1 |
| Show Module # | Since: base-4.9.0.0 |
| Show TrName # | Since: base-4.9.0.0 |
| Show KindRep # | |
| Show TypeLitSort # | Since: base-4.11.0.0 |
| Show SomeException # | Since: base-3.0 |
Defined in GHC.Exception.Type | |
| Show SrcLoc # | Since: base-4.9.0.0 |
| Show Version # | Since: base-2.1 |
| Show GeneralCategory # | Since: base-2.1 |
Defined in GHC.Unicode | |
| Show Number # | Since: base-4.6.0.0 |
| Show Lexeme # | Since: base-2.1 |
| Show Fingerprint # | Since: base-4.7.0.0 |
Defined in GHC.Fingerprint.Type | |
| Show IOMode # | Since: base-4.2.0.0 |
| Show SomeNat # | Since: base-4.7.0.0 |
| Show SomeSymbol # | Since: base-4.7.0.0 |
Defined in GHC.TypeLits | |
| Show IntPtr # | |
| Show WordPtr # | |
| Show CUIntMax # | |
| Show CIntMax # | |
| Show CUIntPtr # | |
| Show CIntPtr # | |
| Show CSUSeconds # | |
Defined in Foreign.C.Types | |
| Show CUSeconds # | |
| Show CTime # | |
| Show CClock # | |
| Show CSigAtomic # | |
Defined in Foreign.C.Types | |
| Show CWchar # | |
| Show CSize # | |
| Show CPtrdiff # | |
| Show CDouble # | |
| Show CFloat # | |
| Show CBool # | |
| Show CULLong # | |
| Show CLLong # | |
| Show CULong # | |
| Show CLong # | |
| Show CUInt # | |
| Show CInt # | |
| Show CUShort # | |
| Show CShort # | |
| Show CUChar # | |
| Show CSChar # | |
| Show CChar # | |
| Show DecidedStrictness # | Since: base-4.9.0.0 |
Defined in GHC.Generics | |
| Show SourceStrictness # | Since: base-4.9.0.0 |
Defined in GHC.Generics | |
| Show SourceUnpackedness # | Since: base-4.9.0.0 |
Defined in GHC.Generics | |
| Show Associativity # | Since: base-4.6.0.0 |
Defined in GHC.Generics | |
| Show Fixity # | Since: base-4.6.0.0 |
| Show Any # | Since: base-2.1 |
| Show All # | Since: base-2.1 |
| Show Lifetime # | Since: base-4.8.1.0 |
| Show Event # | Since: base-4.4.0.0 |
| Show ArithException # | Since: base-4.0.0.0 |
Defined in GHC.Exception.Type | |
| Show ErrorCall # | Since: base-4.0.0.0 |
| Show FileLockingNotSupported # | Since: base-4.10.0.0 |
Defined in GHC.IO.Handle.Lock.Common | |
| Show IOException # | Since: base-4.1.0.0 |
Defined in GHC.IO.Exception | |
| Show MaskingState # | Since: base-4.3.0.0 |
| Show CodingProgress # | Since: base-4.4.0.0 |
Defined in GHC.IO.Encoding.Types | |
| Show TextEncoding # | Since: base-4.3.0.0 |
Defined in GHC.IO.Encoding.Types | |
| Show SeekMode # | Since: base-4.2.0.0 |
| Show NewlineMode # | Since: base-4.3.0.0 |
Defined in GHC.IO.Handle.Types | |
| Show Newline # | Since: base-4.3.0.0 |
| Show BufferMode # | Since: base-4.2.0.0 |
Defined in GHC.IO.Handle.Types | |
| Show HandleType # | Since: base-4.1.0.0 |
Defined in GHC.IO.Handle.Types | |
| Show Handle # | Since: base-4.1.0.0 |
| Show IOErrorType # | Since: base-4.1.0.0 |
Defined in GHC.IO.Exception | |
| Show ExitCode # | |
| Show FixIOException # | Since: base-4.11.0.0 |
Defined in GHC.IO.Exception | |
| Show ArrayException # | Since: base-4.1.0.0 |
Defined in GHC.IO.Exception | |
| Show AsyncException # | Since: base-4.1.0.0 |
Defined in GHC.IO.Exception | |
| Show SomeAsyncException # | Since: base-4.7.0.0 |
Defined in GHC.IO.Exception | |
| Show AssertionFailed # | Since: base-4.1.0.0 |
Defined in GHC.IO.Exception | |
| Show CompactionFailed # | Since: base-4.10.0.0 |
Defined in GHC.IO.Exception | |
| Show AllocationLimitExceeded # | Since: base-4.7.1.0 |
Defined in GHC.IO.Exception | |
| Show Deadlock # | Since: base-4.1.0.0 |
| Show BlockedIndefinitelyOnSTM # | Since: base-4.1.0.0 |
Defined in GHC.IO.Exception | |
| Show BlockedIndefinitelyOnMVar # | Since: base-4.1.0.0 |
Defined in GHC.IO.Exception | |
| Show CodingFailureMode # | Since: base-4.4.0.0 |
Defined in GHC.IO.Encoding.Failure | |
| Show Fd # | |
| Show CNfds # | |
| Show CSocklen # | |
| Show CTimer # | |
| Show CKey # | |
| Show CId # | |
| Show CFsFilCnt # | |
| Show CFsBlkCnt # | |
| Show CClockId # | |
| Show CBlkCnt # | |
| Show CBlkSize # | |
| Show CRLim # | |
| Show CTcflag # | |
| Show CSpeed # | |
| Show CCc # | |
| Show CUid # | |
| Show CNlink # | |
| Show CGid # | |
| Show CSsize # | |
| Show CPid # | |
| Show COff # | |
| Show CMode # | |
| Show CIno # | |
| Show CDev # | |
| Show RTSFlags # | Since: base-4.8.0.0 |
| Show ParFlags # | Since: base-4.8.0.0 |
| Show TickyFlags # | Since: base-4.8.0.0 |
Defined in GHC.RTS.Flags | |
| Show TraceFlags # | Since: base-4.8.0.0 |
Defined in GHC.RTS.Flags | |
| Show DoTrace # | Since: base-4.8.0.0 |
| Show ProfFlags # | Since: base-4.8.0.0 |
| Show DoHeapProfile # | Since: base-4.8.0.0 |
Defined in GHC.RTS.Flags | |
| Show CCFlags # | Since: base-4.8.0.0 |
| Show DoCostCentres # | Since: base-4.8.0.0 |
Defined in GHC.RTS.Flags | |
| Show DebugFlags # | Since: base-4.8.0.0 |
Defined in GHC.RTS.Flags | |
| Show MiscFlags # | Since: base-4.8.0.0 |
| Show ConcFlags # | Since: base-4.8.0.0 |
| Show GCFlags # | Since: base-4.8.0.0 |
| Show IoSubSystem # | |
Defined in GHC.RTS.Flags | |
| Show GiveGCStats # | Since: base-4.8.0.0 |
Defined in GHC.RTS.Flags | |
| Show Dynamic # | Since: base-2.1 |
| Show ThreadStatus # | Since: base-4.3.0.0 |
Defined in GHC.Conc.Sync | |
| Show BlockReason # | Since: base-4.3.0.0 |
Defined in GHC.Conc.Sync | |
| Show ThreadId # | Since: base-4.2.0.0 |
| Show NestedAtomically # | Since: base-4.0 |
Defined in Control.Exception.Base | |
| Show NonTermination # | Since: base-4.0 |
Defined in Control.Exception.Base | |
| Show TypeError # | Since: base-4.9.0.0 |
| Show NoMethodError # | Since: base-4.0 |
Defined in Control.Exception.Base | |
| Show RecUpdError # | Since: base-4.0 |
Defined in Control.Exception.Base | |
| Show RecConError # | Since: base-4.0 |
Defined in Control.Exception.Base | |
| Show RecSelError # | Since: base-4.0 |
Defined in Control.Exception.Base | |
| Show PatternMatchFail # | Since: base-4.0 |
Defined in Control.Exception.Base | |
| Show FdKey # | Since: base-4.4.0.0 |
| Show FD # | Since: base-4.1.0.0 |
| Show HandlePosn # | Since: base-4.1.0.0 |
Defined in GHC.IO.Handle | |
| Show StaticPtrInfo # | Since: base-4.8.0.0 |
Defined in GHC.StaticPtr | |
| Show ByteOrder # | Since: base-4.11.0.0 |
| Show GCDetails # | Since: base-4.10.0.0 |
| Show RTSStats # | Since: base-4.10.0.0 |
| Show Timeout # | Since: base-4.0 |
| Show Fixity # | Since: base-4.0.0.0 |
| Show ConstrRep # | Since: base-4.0.0.0 |
| Show DataRep # | Since: base-4.0.0.0 |
| Show Constr # | Since: base-4.0.0.0 |
| Show DataType # | Since: base-4.0.0.0 |
| Show Void # | Since: base-4.8.0.0 |
| Show a => Show [a] # | Since: base-2.1 |
| Show a => Show (Maybe a) # | Since: base-2.1 |
| Show a => Show (Ratio a) # | Since: base-2.0.1 |
| Show (Ptr a) # | Since: base-2.1 |
| Show (FunPtr a) # | Since: base-2.1 |
| Show p => Show (Par1 p) # | Since: base-4.7.0.0 |
| Show a => Show (a) # | Since: base-4.15 |
| Show a => Show (NonEmpty a) # | Since: base-4.11.0.0 |
| Show a => Show (Down a) # | This instance would be equivalent to the derived instances of the
Since: base-4.7.0.0 |
| Show a => Show (Product a) # | Since: base-2.1 |
| Show a => Show (Sum a) # | Since: base-2.1 |
| Show a => Show (Dual a) # | Since: base-2.1 |
| Show a => Show (Last a) # | Since: base-2.1 |
| Show a => Show (First a) # | Since: base-2.1 |
| Show (ForeignPtr a) # | Since: base-2.1 |
Defined in GHC.ForeignPtr | |
| Show a => Show (Identity a) # | This instance would be equivalent to the derived instances of the
Since: base-4.8.0.0 |
| Show a => Show (ZipList a) # | Since: base-4.7.0.0 |
| Show a => Show (Option a) # | Since: base-4.9.0.0 |
| Show m => Show (WrappedMonoid m) # | Since: base-4.9.0.0 |
Defined in Data.Semigroup | |
| Show a => Show (Last a) # | Since: base-4.9.0.0 |
| Show a => Show (First a) # | Since: base-4.9.0.0 |
| Show a => Show (Max a) # | Since: base-4.9.0.0 |
| Show a => Show (Min a) # | Since: base-4.9.0.0 |
| Show a => Show (Complex a) # | Since: base-2.1 |
| Show (a -> b) # | Since: base-2.1 |
| (Show a, Show b) => Show (Either a b) # | Since: base-3.0 |
| Show (V1 p) # | Since: base-4.9.0.0 |
| Show (U1 p) # | Since: base-4.9.0.0 |
| Show (TypeRep a) # | |
| (Show a, Show b) => Show (a, b) # | Since: base-2.1 |
| Show (ST s a) # | Since: base-2.1 |
| (Ix a, Show a, Show b) => Show (Array a b) # | Since: base-2.1 |
| Show (Proxy s) # | Since: base-4.7.0.0 |
| (Show a, Show b) => Show (Arg a b) # | Since: base-4.9.0.0 |
| HasResolution a => Show (Fixed a) # | Since: base-2.1 |
| Show (f p) => Show (Rec1 f p) # | Since: base-4.7.0.0 |
| Show (URec Word p) # | Since: base-4.9.0.0 |
| Show (URec Int p) # | Since: base-4.9.0.0 |
| Show (URec Float p) # | |
| Show (URec Double p) # | Since: base-4.9.0.0 |
| Show (URec Char p) # | Since: base-4.9.0.0 |
| (Show a, Show b, Show c) => Show (a, b, c) # | Since: base-2.1 |
| Show (a :~: b) # | Since: base-4.7.0.0 |
| Show (Coercion a b) # | Since: base-4.7.0.0 |
| Show (f a) => Show (Alt f a) # | Since: base-4.8.0.0 |
| Show (f a) => Show (Ap f a) # | Since: base-4.12.0.0 |
| Show a => Show (Const a b) # | This instance would be equivalent to the derived instances of the
Since: base-4.8.0.0 |
| Show c => Show (K1 i c p) # | Since: base-4.7.0.0 |
| (Show (f p), Show (g p)) => Show ((f :+: g) p) # | Since: base-4.7.0.0 |
| (Show (f p), Show (g p)) => Show ((f :*: g) p) # | Since: base-4.7.0.0 |
| (Show a, Show b, Show c, Show d) => Show (a, b, c, d) # | Since: base-2.1 |
| Show (a :~~: b) # | Since: base-4.10.0.0 |
| (Show1 f, Show1 g, Show a) => Show (Sum f g a) # | Since: base-4.9.0.0 |
| (Show1 f, Show1 g, Show a) => Show (Product f g a) # | Since: base-4.9.0.0 |
| Show (f p) => Show (M1 i c f p) # | Since: base-4.7.0.0 |
| Show (f (g p)) => Show ((f :.: g) p) # | Since: base-4.7.0.0 |
| (Show a, Show b, Show c, Show d, Show e) => Show (a, b, c, d, e) # | Since: base-2.1 |
| (Show1 f, Show1 g, Show a) => Show (Compose f g a) # | Since: base-4.9.0.0 |
| (Show a, Show b, Show c, Show d, Show e, Show f) => Show (a, b, c, d, e, f) # | Since: base-2.1 |
| (Show a, Show b, Show c, Show d, Show e, Show f, Show g) => Show (a, b, c, d, e, f, g) # | Since: base-2.1 |
| (Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h) => Show (a, b, c, d, e, f, g, h) # | Since: base-2.1 |
| (Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i) => Show (a, b, c, d, e, f, g, h, i) # | Since: base-2.1 |
| (Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j) => Show (a, b, c, d, e, f, g, h, i, j) # | Since: base-2.1 |
| (Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j, Show k) => Show (a, b, c, d, e, f, g, h, i, j, k) # | Since: base-2.1 |
| (Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j, Show k, Show l) => Show (a, b, c, d, e, f, g, h, i, j, k, l) # | Since: base-2.1 |
| (Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j, Show k, Show l, Show m) => Show (a, b, c, d, e, f, g, h, i, j, k, l, m) # | Since: base-2.1 |
| (Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j, Show k, Show l, Show m, Show n) => Show (a, b, c, d, e, f, g, h, i, j, k, l, m, n) # | Since: base-2.1 |
| (Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h, Show i, Show j, Show k, Show l, Show m, Show n, Show o) => Show (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) # | Since: base-2.1 |
showChar :: Char -> ShowS Source #
utility function converting a Char to a show function that
simply prepends the character unchanged.
showString :: String -> ShowS Source #
utility function converting a String to a show function that
simply prepends the string unchanged.
showMultiLineString :: String -> [String] Source #
Like showLitString (expand escape characters using Haskell
escape conventions), but
* break the string into multiple lines
* wrap the entire thing in double quotes
Example: showMultiLineString "hellongoodbyenblah"
returns [""hello\n\", "\goodbyen\", "\blah""]
showList__ :: (a -> ShowS) -> [a] -> ShowS Source #
showLitChar :: Char -> ShowS Source #
Convert a character to a string using only printable characters, using Haskell source-language escape conventions. For example:
showLitChar '\n' s = "\\n" ++ s
showLitString :: String -> ShowS Source #
Same as showLitChar, but for strings
It converts the string to a string using Haskell escape conventions
for non-printable characters. Does not add double-quotes around the
whole thing; the caller should do that.
The main difference from showLitChar (apart from the fact that the
argument is a string not a list) is that we must escape double-quotes
intToDigit :: Int -> Char Source #