[project @ 2003-05-30 09:19:39 by simonpj]

[ghc-base.git] / GHC / Show.lhs

diff --git a/GHC/Show.lhs b/GHC/Show.lhs
index b0265be..1401241 100644 (file)
--- a/GHC/Show.lhs
+++ b/GHC/Show.lhs
@@ -1,14 +1,18 @@
-% ------------------------------------------------------------------------------
-% $Id: Show.lhs,v 1.5 2002/04/11 12:03:44 simonpj Exp $
-%
-% (c) The University of Glasgow, 1992-2000
-%
-
-\section{Module @GHC.Show@}
-
-
 \begin{code}
 {-# OPTIONS -fno-implicit-prelude #-}
+-----------------------------------------------------------------------------
+-- |
+-- 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.
+--
+-----------------------------------------------------------------------------
 
 module GHC.Show
        (
@@ -20,6 +24,7 @@ module GHC.Show
        shows, showChar, showString, showParen, showList__, showSpace,
        showLitChar, protectEsc, 
        intToDigit, digitToInt, showSignedInt,
+       appPrec, appPrec1,
 
        -- Character operations
        isAscii, isLatin1, isControl, isPrint, isSpace, isUpper,
@@ -70,6 +75,12 @@ showList__ showx (x:xs) s = '[' : showx x (showl xs)
   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}
 
 %*********************************************************
@@ -113,19 +124,18 @@ instance Show Int where
 
 instance Show a => Show (Maybe a) where
     showsPrec _p Nothing s = showString "Nothing" s
-    showsPrec (I# p#) (Just x) s
-                          = (showParen (p# >=# 10#) $ 
+    showsPrec p (Just x) s
+                          = (showParen (p > appPrec) $ 
                             showString "Just " . 
-                            showsPrec (I# 10#) x) s
+                            showsPrec appPrec1 x) s
 
 instance (Show a, Show b) => Show (Either a b) where
-    showsPrec (I# p#) e s =
-       (showParen (p# >=# 10#) $
+    showsPrec p e s =
+       (showParen (p > appPrec) $
         case e of
-         Left  a -> showString "Left "  . showsPrec (I# 10#) a
-        Right b -> showString "Right " . showsPrec (I# 10#) b)
+         Left  a -> showString "Left "  . showsPrec appPrec1 a
+        Right b -> showString "Right " . showsPrec appPrec1 b)
        s
-
 \end{code}