-% ------------------------------------------------------------------------------
-% $Id: Show.lhs,v 1.1 2001/06/28 14:15:03 simonmar Exp $
-%
-% (c) The University of Glasgow, 1992-2000
-%
-
-\section{Module @GHC.Show@}
-
-
\begin{code}
-{-# OPTIONS -fno-implicit-prelude #-}
-
+{-# LANGUAGE NoImplicitPrelude, BangPatterns, MagicHash #-}
+{-# OPTIONS_HADDOCK hide #-}
+
+-----------------------------------------------------------------------------
+-- |
+-- Module : GHC.Show
+-- 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)
+--
+-- The 'Show' class, and related operations.
+--
+-----------------------------------------------------------------------------
+
+-- #hide
module GHC.Show
- (
- Show(..), ShowS,
-
- -- Instances for Show: (), [], Bool, Ordering, Int, Char
+ (
+ Show(..), ShowS,
- -- Show support code
- shows, showChar, showString, showParen, showList__, showSpace,
- showLitChar, protectEsc,
- intToDigit, showSignedInt,
+ -- Instances for Show: (), [], Bool, Ordering, Int, Char
- -- Character operations
- isAscii, isLatin1, isControl, isPrint, isSpace, isUpper,
- isLower, isAlpha, isDigit, isOctDigit, isHexDigit, isAlphaNum,
- toUpper, toLower,
- asciiTab,
+ -- Show support code
+ shows, showChar, showString, showMultiLineString,
+ showParen, showList__, showSpace,
+ showLitChar, showLitString, protectEsc,
+ intToDigit, showSignedInt,
+ appPrec, appPrec1,
- -- String operations
- lines, unlines, words, unwords
- )
- where
+ -- Character operations
+ asciiTab,
+ )
+ where
-import {-# SOURCE #-} GHC.Err ( error )
import GHC.Base
-import GHC.Tup
-import GHC.Maybe
-import GHC.List ( (!!), break, dropWhile
-#ifdef USE_REPORT_PRELUDE
- , concatMap, foldr1
-#endif
- )
+import Data.Maybe
+import GHC.List ((!!), foldr1, break)
\end{code}
%*********************************************************
-%* *
+%* *
\subsection{The @Show@ class}
-%* *
+%* *
%*********************************************************
\begin{code}
+-- | The @shows@ functions return a function that prepends the
+-- output 'String' to an existing 'String'. This allows constant-time
+-- concatenation of results using function composition.
type ShowS = String -> String
+-- | Conversion of values to readable 'String's.
+--
+-- Minimal complete definition: 'showsPrec' or 'show'.
+--
+-- Derived instances of 'Show' have the following properties, which
+-- are compatible with derived instances of 'Text.Read.Read':
+--
+-- * The result of 'show' is 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
+-- 'showsPrec' will produce infix applications of the constructor.
+--
+-- * the representation will be enclosed in parentheses if the
+-- precedence of the top-level constructor in @x@ is less than @d@
+-- (associativity is ignored). Thus, if @d@ is @0@ then the result
+-- is never surrounded in parentheses; if @d@ is @11@ it is always
+-- surrounded in parentheses, unless it is an atomic expression.
+--
+-- * If the constructor is defined using record syntax, then 'show'
+-- will 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 = 5
+--
+-- Note that right-associativity of @:^:@ is ignored. For example,
+--
+-- * @'show' (Leaf 1 :^: Leaf 2 :^: Leaf 3)@ produces the string
+-- @\"Leaf 1 :^: (Leaf 2 :^: Leaf 3)\"@.
+
class Show a where
- showsPrec :: Int -> 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 'Text.Read.Read' and 'Show' satisfy the following:
+ --
+ -- * @(x,\"\")@ is an element of
+ -- @('Text.Read.readsPrec' d ('showsPrec' d x \"\"))@.
+ --
+ -- That is, 'Text.Read.readsPrec' parses the string produced by
+ -- 'showsPrec', and delivers the value that 'showsPrec' started with.
+
+ showsPrec :: Int -- ^ the operator precedence of the enclosing
+ -- context (a number from @0@ to @11@).
+ -- Function application has precedence @10@.
+ -> a -- ^ the value to be converted to a 'String'
+ -> ShowS
+
+ -- | A specialised variant of 'showsPrec', using precedence context
+ -- zero, and returning an ordinary 'String'.
show :: a -> String
+
+ -- | The method 'showList' is provided to allow the programmer to
+ -- give a specialised way of showing lists of values.
+ -- For example, this is used by the predefined 'Show' instance of
+ -- the 'Char' type, where values of type 'String' should be shown
+ -- in double quotes, rather than between square brackets.
showList :: [a] -> ShowS
showsPrec _ x s = show x ++ s
where
showl [] = ']' : s
showl (y:ys) = ',' : showx y (showl ys)
+
+appPrec, appPrec1 :: Int
+ -- Use unboxed stuff because we don't have overloaded numerics yet
+appPrec = I# 10# -- Precedence of application:
+ -- one more than the maximum operator precedence of 9
+appPrec1 = I# 11# -- appPrec + 1
\end{code}
%*********************************************************
-%* *
+%* *
\subsection{Simple Instances}
-%* *
+%* *
%*********************************************************
\begin{code}
showsPrec _ '\'' = showString "'\\''"
showsPrec _ c = showChar '\'' . showLitChar c . showChar '\''
- showList cs = showChar '"' . showl cs
- where showl "" s = showChar '"' s
- showl ('"':xs) s = showString "\\\"" (showl xs s)
- showl (x:xs) s = showLitChar x (showl xs s)
- -- Making 's' an explicit parameter makes it clear to GHC
- -- that showl has arity 2, which avoids it allocating an extra lambda
- -- The sticking point is the recursive call to (showl xs), which
- -- it can't figure out would be ok with arity 2.
+ showList cs = showChar '"' . showLitString cs . showChar '"'
instance Show Int where
showsPrec = showSignedInt
instance Show a => Show (Maybe a) where
showsPrec _p Nothing s = showString "Nothing" s
- showsPrec (I# p#) (Just x) s
- = (showParen (p# >=# 10#) $
- showString "Just " .
- showsPrec (I# 10#) x) s
-
-instance (Show a, Show b) => Show (Either a b) where
- showsPrec (I# p#) e s =
- (showParen (p# >=# 10#) $
- case e of
- Left a -> showString "Left " . showsPrec (I# 10#) a
- Right b -> showString "Right " . showsPrec (I# 10#) b)
- s
-
+ showsPrec p (Just x) s
+ = (showParen (p > appPrec) $
+ showString "Just " .
+ showsPrec appPrec1 x) s
\end{code}
%*********************************************************
-%* *
+%* *
\subsection{Show instances for the first few tuples
-%* *
+%* *
%*********************************************************
\begin{code}
-- The explicit 's' parameters are important
-- Otherwise GHC thinks that "shows x" might take a lot of work to compute
-- and generates defns like
--- showsPrec _ (x,y) = let sx = shows x; sy = shows y in
--- \s -> showChar '(' (sx (showChar ',' (sy (showChar ')' s))))
+-- showsPrec _ (x,y) = let sx = shows x; sy = shows y in
+-- \s -> showChar '(' (sx (showChar ',' (sy (showChar ')' s))))
instance (Show a, Show b) => Show (a,b) where
- showsPrec _ (x,y) s = (showChar '(' . shows x . showChar ',' .
- shows y . showChar ')')
- s
+ showsPrec _ (a,b) s = show_tuple [shows a, shows b] s
instance (Show a, Show b, Show c) => Show (a, b, c) where
- showsPrec _ (x,y,z) s = (showChar '(' . shows x . showChar ',' .
- shows y . showChar ',' .
- shows z . showChar ')')
- s
+ showsPrec _ (a,b,c) s = show_tuple [shows a, shows b, shows c] s
instance (Show a, Show b, Show c, Show d) => Show (a, b, c, d) where
- showsPrec _ (w,x,y,z) s = (showChar '(' . shows w . showChar ',' .
- shows x . showChar ',' .
- shows y . showChar ',' .
- shows z . showChar ')')
- s
+ showsPrec _ (a,b,c,d) s = show_tuple [shows a, shows b, shows c, shows d] s
instance (Show a, Show b, Show c, Show d, Show e) => Show (a, b, c, d, e) where
- showsPrec _ (v,w,x,y,z) s = (showChar '(' . shows v . showChar ',' .
- shows w . showChar ',' .
- shows x . showChar ',' .
- shows y . showChar ',' .
- shows z . showChar ')')
- s
+ showsPrec _ (a,b,c,d,e) s = show_tuple [shows a, shows b, shows c, shows d, shows e] s
+
+instance (Show a, Show b, Show c, Show d, Show e, Show f) => Show (a,b,c,d,e,f) where
+ showsPrec _ (a,b,c,d,e,f) s = show_tuple [shows a, shows b, shows c, shows d, shows e, shows f] s
+
+instance (Show a, Show b, Show c, Show d, Show e, Show f, Show g)
+ => Show (a,b,c,d,e,f,g) where
+ showsPrec _ (a,b,c,d,e,f,g) s
+ = show_tuple [shows a, shows b, shows c, shows d, shows e, shows f, shows g] s
+
+instance (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) where
+ showsPrec _ (a,b,c,d,e,f,g,h) s
+ = show_tuple [shows a, shows b, shows c, shows d, shows e, shows f, shows g, shows h] s
+
+instance (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) where
+ showsPrec _ (a,b,c,d,e,f,g,h,i) s
+ = show_tuple [shows a, shows b, shows c, shows d, shows e, shows f, shows g, shows h,
+ shows i] s
+
+instance (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) where
+ showsPrec _ (a,b,c,d,e,f,g,h,i,j) s
+ = show_tuple [shows a, shows b, shows c, shows d, shows e, shows f, shows g, shows h,
+ shows i, shows j] s
+
+instance (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) where
+ showsPrec _ (a,b,c,d,e,f,g,h,i,j,k) s
+ = show_tuple [shows a, shows b, shows c, shows d, shows e, shows f, shows g, shows h,
+ shows i, shows j, shows k] s
+
+instance (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) where
+ showsPrec _ (a,b,c,d,e,f,g,h,i,j,k,l) s
+ = show_tuple [shows a, shows b, shows c, shows d, shows e, shows f, shows g, shows h,
+ shows i, shows j, shows k, shows l] s
+
+instance (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) where
+ showsPrec _ (a,b,c,d,e,f,g,h,i,j,k,l,m) s
+ = show_tuple [shows a, shows b, shows c, shows d, shows e, shows f, shows g, shows h,
+ shows i, shows j, shows k, shows l, shows m] s
+
+instance (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) where
+ showsPrec _ (a,b,c,d,e,f,g,h,i,j,k,l,m,n) s
+ = show_tuple [shows a, shows b, shows c, shows d, shows e, shows f, shows g, shows h,
+ shows i, shows j, shows k, shows l, shows m, shows n] s
+
+instance (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) where
+ showsPrec _ (a,b,c,d,e,f,g,h,i,j,k,l,m,n,o) s
+ = show_tuple [shows a, shows b, shows c, shows d, shows e, shows f, shows g, shows h,
+ shows i, shows j, shows k, shows l, shows m, shows n, shows o] s
+
+show_tuple :: [ShowS] -> ShowS
+show_tuple ss = showChar '('
+ . foldr1 (\s r -> s . showChar ',' . r) ss
+ . showChar ')'
\end{code}
%*********************************************************
-%* *
+%* *
\subsection{Support code for @Show@}
-%* *
+%* *
%*********************************************************
\begin{code}
+-- | equivalent to 'showsPrec' with a precedence of 0.
shows :: (Show a) => a -> ShowS
shows = showsPrec zeroInt
+-- | utility function converting a 'Char' to a show function that
+-- simply prepends the character unchanged.
showChar :: Char -> ShowS
showChar = (:)
+-- | utility function converting a 'String' to a show function that
+-- simply prepends the string unchanged.
showString :: String -> ShowS
showString = (++)
+-- | utility function that surrounds the inner show function with
+-- parentheses when the 'Bool' parameter is 'True'.
showParen :: Bool -> ShowS -> ShowS
showParen b p = if b then showChar '(' . p . showChar ')' else p
Code specific for characters
\begin{code}
-showLitChar :: Char -> ShowS
-showLitChar c s | c > '\DEL' = showChar '\\' (protectEsc isDigit (shows (ord c)) s)
-showLitChar '\DEL' s = showString "\\DEL" s
-showLitChar '\\' s = showString "\\\\" s
+-- | Convert a character to a string using only printable characters,
+-- using Haskell source-language escape conventions. For example:
+--
+-- > showLitChar '\n' s = "\\n" ++ s
+--
+showLitChar :: Char -> ShowS
+showLitChar c s | c > '\DEL' = showChar '\\' (protectEsc isDec (shows (ord c)) s)
+showLitChar '\DEL' s = showString "\\DEL" s
+showLitChar '\\' s = showString "\\\\" s
showLitChar c s | c >= ' ' = showChar c s
-showLitChar '\a' s = showString "\\a" s
-showLitChar '\b' s = showString "\\b" s
-showLitChar '\f' s = showString "\\f" s
-showLitChar '\n' s = showString "\\n" s
-showLitChar '\r' s = showString "\\r" s
-showLitChar '\t' s = showString "\\t" s
-showLitChar '\v' s = showString "\\v" s
-showLitChar '\SO' s = protectEsc (== 'H') (showString "\\SO") s
-showLitChar c s = showString ('\\' : asciiTab!!ord c) s
- -- I've done manual eta-expansion here, becuase otherwise it's
- -- impossible to stop (asciiTab!!ord) getting floated out as an MFE
+showLitChar '\a' s = showString "\\a" s
+showLitChar '\b' s = showString "\\b" s
+showLitChar '\f' s = showString "\\f" s
+showLitChar '\n' s = showString "\\n" s
+showLitChar '\r' s = showString "\\r" s
+showLitChar '\t' s = showString "\\t" s
+showLitChar '\v' s = showString "\\v" s
+showLitChar '\SO' s = protectEsc (== 'H') (showString "\\SO") s
+showLitChar c s = showString ('\\' : asciiTab!!ord c) s
+ -- I've done manual eta-expansion here, becuase otherwise it's
+ -- impossible to stop (asciiTab!!ord) getting floated out as an MFE
+
+showLitString :: String -> ShowS
+-- | 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
+showLitString [] s = s
+showLitString ('"' : cs) s = showString "\\\"" (showLitString cs s)
+showLitString (c : cs) s = showLitChar c (showLitString cs s)
+ -- Making 's' an explicit parameter makes it clear to GHC that
+ -- showLitString has arity 2, which avoids it allocating an extra lambda
+ -- The sticking point is the recursive call to (showLitString cs), which
+ -- it can't figure out would be ok with arity 2.
+
+showMultiLineString :: String -> [String]
+-- | Like 'showLitString' (expand escape characters using Haskell
+-- escape conventions), but
+-- * break the string into multiple lines
+-- * wrap the entire thing in double quotes
+-- Example: @breakMultiLineString "hello\ngoodbye\nblah"@
+-- returns @["\"hello\\", "\\goodbye\\", "\\blah\"" ]@
+-- where those "\\" are really just a single backslash
+-- (but I'm writing them here as Haskell literals)
+showMultiLineString str
+ = go '\"' str
+ where
+ go ch s = case break (== '\n') s of
+ (l, _:s'@(_:_)) -> (ch : showLitString l "\\") : go '\\' s'
+ (l, _) -> [ch : showLitString l "\""]
+
+isDec :: Char -> Bool
+isDec c = c >= '0' && c <= '9'
protectEsc :: (Char -> Bool) -> ShowS -> ShowS
-protectEsc p f = f . cont
- where cont s@(c:_) | p c = "\\&" ++ s
- cont s = s
+protectEsc p f = f . cont
+ where cont s@(c:_) | p c = "\\&" ++ s
+ cont s = s
-intToDigit :: Int -> Char
-intToDigit (I# i)
- | i >=# 0# && i <=# 9# = unsafeChr (ord '0' `plusInt` I# i)
- | i >=# 10# && i <=# 15# = unsafeChr (ord 'a' `minusInt` I# 10# `plusInt` I# i)
- | otherwise = error ("Char.intToDigit: not a digit " ++ show (I# i))
+asciiTab :: [String]
+asciiTab = -- Using an array drags in the array module. listArray ('\NUL', ' ')
+ ["NUL", "SOH", "STX", "ETX", "EOT", "ENQ", "ACK", "BEL",
+ "BS", "HT", "LF", "VT", "FF", "CR", "SO", "SI",
+ "DLE", "DC1", "DC2", "DC3", "DC4", "NAK", "SYN", "ETB",
+ "CAN", "EM", "SUB", "ESC", "FS", "GS", "RS", "US",
+ "SP"]
\end{code}
Code specific for Ints.
\begin{code}
+-- | Convert an 'Int' in the range @0@..@15@ to the corresponding single
+-- digit 'Char'. This function fails on other inputs, and generates
+-- lower-case hexadecimal digits.
+intToDigit :: Int -> Char
+intToDigit (I# i)
+ | i >=# 0# && i <=# 9# = unsafeChr (ord '0' `plusInt` I# i)
+ | i >=# 10# && i <=# 15# = unsafeChr (ord 'a' `minusInt` ten `plusInt` I# i)
+ | otherwise = error ("Char.intToDigit: not a digit " ++ show (I# i))
+
+ten :: Int
+ten = I# 10#
+
showSignedInt :: Int -> Int -> ShowS
showSignedInt (I# p) (I# n) r
| n <# 0# && p ># 6# = '(' : itos n (')' : r)
itos :: Int# -> String -> String
itos n# cs
- | n# <# 0# = let
- n'# = negateInt# n#
- in if n'# <# 0# -- minInt?
- then '-' : itos' (negateInt# (n'# `quotInt#` 10#))
- (itos' (negateInt# (n'# `remInt#` 10#)) cs)
- else '-' : itos' n'# cs
+ | n# <# 0# =
+ let !(I# minInt#) = minInt in
+ if n# ==# minInt#
+ -- negateInt# minInt overflows, so we can't do that:
+ then '-' : itos' (negateInt# (n# `quotInt#` 10#))
+ (itos' (negateInt# (n# `remInt#` 10#)) cs)
+ else '-' : itos' (negateInt# n#) cs
| otherwise = itos' n# cs
where
itos' :: Int# -> String -> String
- itos' n# cs
- | n# <# 10# = C# (chr# (ord# '0'# +# n#)) : cs
- | otherwise = itos' (n# `quotInt#` 10#)
- (C# (chr# (ord# '0'# +# (n# `remInt#` 10#))) : cs)
-\end{code}
-
-%*********************************************************
-%* *
-\subsection{Character stuff}
-%* *
-%*********************************************************
-
-\begin{code}
-isAscii, isLatin1, isControl, isPrint, isSpace, isUpper,
- isLower, isAlpha, isDigit, isOctDigit, isHexDigit, isAlphaNum,
- isAsciiUpper, isAsciiLower :: Char -> Bool
-isAscii c = c < '\x80'
-isLatin1 c = c <= '\xff'
-isControl c = c < ' ' || c >= '\DEL' && c <= '\x9f'
-isPrint c = not (isControl c)
-
--- isSpace includes non-breaking space
--- Done with explicit equalities both for efficiency, and to avoid a tiresome
--- recursion with GHC.List elem
-isSpace c = c == ' ' ||
- c == '\t' ||
- c == '\n' ||
- c == '\r' ||
- c == '\f' ||
- c == '\v' ||
- c == '\xa0'
-
--- The upper case ISO characters have the multiplication sign dumped
--- randomly in the middle of the range. Go figure.
-isUpper c = c >= 'A' && c <= 'Z' ||
- c >= '\xC0' && c <= '\xD6' ||
- c >= '\xD8' && c <= '\xDE'
--- The lower case ISO characters have the division sign dumped
--- randomly in the middle of the range. Go figure.
-isLower c = c >= 'a' && c <= 'z' ||
- c >= '\xDF' && c <= '\xF6' ||
- c >= '\xF8' && c <= '\xFF'
-isAsciiLower c = c >= 'a' && c <= 'z'
-isAsciiUpper c = c >= 'A' && c <= 'Z'
-
-isAlpha c = isLower c || isUpper c
-isDigit c = c >= '0' && c <= '9'
-isOctDigit c = c >= '0' && c <= '7'
-isHexDigit c = isDigit c || c >= 'A' && c <= 'F' ||
- c >= 'a' && c <= 'f'
-isAlphaNum c = isAlpha c || isDigit c
-
--- Case-changing operations
-
-toUpper, toLower :: Char -> Char
-toUpper c@(C# c#)
- | isAsciiLower c = C# (chr# (ord# c# -# 32#))
- | isAscii c = c
- -- fall-through to the slower stuff.
- | isLower c && c /= '\xDF' && c /= '\xFF'
- = unsafeChr (ord c `minusInt` ord 'a' `plusInt` ord 'A')
- | otherwise
- = c
-
-
-
-toLower c@(C# c#)
- | isAsciiUpper c = C# (chr# (ord# c# +# 32#))
- | isAscii c = c
- | isUpper c = unsafeChr (ord c `minusInt` ord 'A' `plusInt` ord 'a')
- | otherwise = c
-
-asciiTab :: [String]
-asciiTab = -- Using an array drags in the array module. listArray ('\NUL', ' ')
- ["NUL", "SOH", "STX", "ETX", "EOT", "ENQ", "ACK", "BEL",
- "BS", "HT", "LF", "VT", "FF", "CR", "SO", "SI",
- "DLE", "DC1", "DC2", "DC3", "DC4", "NAK", "SYN", "ETB",
- "CAN", "EM", "SUB", "ESC", "FS", "GS", "RS", "US",
- "SP"]
+ itos' x# cs'
+ | x# <# 10# = C# (chr# (ord# '0'# +# x#)) : cs'
+ | otherwise = case chr# (ord# '0'# +# (x# `remInt#` 10#)) of { c# ->
+ itos' (x# `quotInt#` 10#) (C# c# : cs') }
\end{code}
-%*********************************************************
-%* *
-\subsection{Functions on strings}
-%* *
-%*********************************************************
-
-lines breaks a string up into a list of strings at newline characters.
-The resulting strings do not contain newlines. Similary, words
-breaks a string up into a list of words, which were delimited by
-white space. unlines and unwords are the inverse operations.
-unlines joins lines with terminating newlines, and unwords joins
-words with separating spaces.
-
-\begin{code}
-lines :: String -> [String]
-lines "" = []
-lines s = let (l, s') = break (== '\n') s
- in l : case s' of
- [] -> []
- (_:s'') -> lines s''
-
-words :: String -> [String]
-words s = case dropWhile {-partain:Char.-}isSpace s of
- "" -> []
- s' -> w : words s''
- where (w, s'') =
- break {-partain:Char.-}isSpace s'
-
-unlines :: [String] -> String
-#ifdef USE_REPORT_PRELUDE
-unlines = concatMap (++ "\n")
-#else
--- HBC version (stolen)
--- here's a more efficient version
-unlines [] = []
-unlines (l:ls) = l ++ '\n' : unlines ls
-#endif
-
-unwords :: [String] -> String
-#ifdef USE_REPORT_PRELUDE
-unwords [] = ""
-unwords ws = foldr1 (\w s -> w ++ ' ':s) ws
-#else
--- HBC version (stolen)
--- here's a more efficient version
-unwords [] = ""
-unwords [w] = w
-unwords (w:ws) = w ++ ' ' : unwords ws
-#endif
-
-\end{code}
projects / ghc-base.git / blobdiff