[project @ 2001-09-18 14:42:33 by simonmar]

[ghc-hetmet.git] / ghc / lib / std / PrelShow.lhs

diff --git a/ghc/lib/std/PrelShow.lhs b/ghc/lib/std/PrelShow.lhs
index c631265..409ab93 100644 (file)
--- a/ghc/lib/std/PrelShow.lhs
+++ b/ghc/lib/std/PrelShow.lhs
@@ -1,6 +1,9 @@
+% ------------------------------------------------------------------------------
+% $Id: PrelShow.lhs,v 1.14 2001/09/18 14:42:33 simonmar Exp $
 %
-% (c) The GRAP/AQUA Project, Glasgow University, 1992-1996
+% (c) The University of Glasgow, 1992-2000
 %
+
 \section{Module @PrelShow@}
 
 
@@ -31,6 +34,7 @@ module PrelShow
 
 import {-# SOURCE #-} PrelErr ( error )
 import PrelBase
+import PrelTup
 import PrelMaybe
 import PrelList        ( (!!), break, dropWhile
 #ifdef USE_REPORT_PRELUDE
@@ -103,18 +107,18 @@ instance  Show Char  where
                -- The sticking point is the recursive call to (showl xs), which
                -- it can't figure out would be ok with arity 2.
 
-instance  Show Int  where
-    showsPrec p n = showSignedInt p n
+instance Show Int where
+    showsPrec = showSignedInt
 
 instance Show a => Show (Maybe a) where
     showsPrec _p Nothing s = showString "Nothing" s
-    showsPrec p@(I# p#) (Just x) 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 p@(I# p#) e s =
+    showsPrec (I# p#) e s =
        (showParen (p# >=# 10#) $
         case e of
          Left  a -> showString "Left "  . showsPrec (I# 10#) a
@@ -192,22 +196,21 @@ Code specific for characters
 
 \begin{code}
 showLitChar               :: Char -> ShowS
-showLitChar c | c > '\DEL' =  \s -> showChar '\\' (protectEsc isDigit (shows (ord c)) s)
-showLitChar '\DEL'        =  showString "\\DEL"
-showLitChar '\\'          =  showString "\\\\"
-showLitChar c | c >= ' '   =  showChar c
-showLitChar '\a'          =  showString "\\a"
-showLitChar '\b'          =  showString "\\b"
-showLitChar '\f'          =  showString "\\f"
-showLitChar '\n'          =  showString "\\n"
-showLitChar '\r'          =  showString "\\r"
-showLitChar '\t'          =  showString "\\t"
-showLitChar '\v'          =  showString "\\v"
-showLitChar '\SO'         =  \s -> protectEsc (== 'H') (showString "\\SO") s
-showLitChar c             =  \s -> showString ('\\' : asciiTab!!ord c) s
-       -- The "\s ->" here means that GHC knows it's ok to put the
-       -- asciiTab!!ord c inside the lambda.  Otherwise we get an extra
-       -- lambda allocated, and that can be pretty bad
+showLitChar c s | c > '\DEL' =  showChar '\\' (protectEsc isDigit (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
 
 protectEsc :: (Char -> Bool) -> ShowS -> ShowS
 protectEsc p f            = f . cont
@@ -216,9 +219,9 @@ protectEsc p f                 = f . cont
 
 intToDigit :: Int -> Char
 intToDigit (I# i)
- | i >=# 0#  && i <=#  9# =  unsafeChr (ord '0' `plusInt` I# i)
- | i >=# 10# && i <=# 15# =  unsafeChr (ord 'a' `plusInt` I# i `minusInt` I# 10#)
- | otherwise             =  error ("Char.intToDigit: not a digit " ++ show (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))
 
 \end{code}
 
@@ -227,26 +230,26 @@ Code specific for Ints.
 \begin{code}
 showSignedInt :: Int -> Int -> ShowS
 showSignedInt (I# p) (I# n) r
-  | n <# 0# && p ># 6# = '(':itos n (')':r)
-  | otherwise         = itos n r
+    | n <# 0# && p ># 6# = '(' : itos n (')' : r)
+    | otherwise          = itos n r
 
 itos :: Int# -> String -> String
-itos n r
-  | n >=# 0#           = itos' n r
-  | negateInt# n <# 0#  = -- n is minInt, a difficult number
-           itos (n `quotInt#` 10#) (itos' (negateInt# (n `remInt#` 10#)) r)
-  | otherwise = '-':itos' (negateInt# n) r
- where
-   itos' :: Int# -> String -> String
-       -- x >= 0
-   itos' x cs 
-     | x <# 10#  = C# (chr# (x +# ord# '0'#)) : cs
-     | otherwise = itos' (x `quotInt#` 10#) 
-                        (C# (chr# (x `remInt#` 10# +# ord# '0'#)) : cs)
+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
+    | otherwise = itos' n# cs
+    where
+    itos' :: Int# -> String -> String
+    itos' n# cs
+        | n# <# 10#  = C# (chr# (ord# '0'# +# n#)) : cs
+        | otherwise = case chr# (ord# '0'# +# (n# `remInt#` 10#)) of { c# ->
+                     itos' (n# `quotInt#` 10#) (C# c# : cs) }
 \end{code}
 
-
-
 %*********************************************************
 %*                                                     *
 \subsection{Character stuff}
@@ -255,7 +258,8 @@ itos n r
 
 \begin{code}
 isAscii, isLatin1, isControl, isPrint, isSpace, isUpper,
- isLower, isAlpha, isDigit, isOctDigit, isHexDigit, isAlphaNum :: Char -> Bool
+ 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'