X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=Data%2FChar.hs;h=c8c630e922435f8307487d1c42ed300e74ecd13c;hb=413f1d5a1537ec712423f84003cc30fbfe399f11;hp=8694f44c69aeee5902d47e7e149896f737115e8d;hpb=d4c5a255b36652a5654b81bf0058d048a8ca165b;p=ghc-base.git

diff --git a/Data/Char.hs b/Data/Char.hs
index 8694f44..c8c630e 100644
--- a/Data/Char.hs
+++ b/Data/Char.hs
@@ -17,23 +17,33 @@ module Data.Char
     (
       Char
 
-    , isAscii, isLatin1, isControl
-    , isPrint, isSpace,  isUpper
-    , isLower, isAlpha,  isDigit
-    , isOctDigit, isHexDigit, isAlphaNum  -- :: Char -> Bool
+    , String
+
+    -- * Character classification
+    -- | Unicode characters are divided into letters, numbers, marks,
+    -- punctuation, symbols, separators (including spaces) and others
+    -- (including control characters).
+    -- The full set of Unicode character attributes is not accessible
+    -- in this library.
+    , isAscii, isLatin1, isControl, isSpace
+    , isLower, isUpper,  isAlpha,   isAlphaNum, isPrint
+    , isDigit, isOctDigit, isHexDigit  -- :: Char -> Bool
 
+    -- * Case conversion
     , toUpper, toLower  -- :: Char -> Char
 
+    -- * Single digit characters
     , digitToInt        -- :: Char -> Int
     , intToDigit        -- :: Int  -> Char
 
+    -- * Numeric representations
     , ord               -- :: Char -> Int
     , chr               -- :: Int  -> Char
-    , readLitChar       -- :: ReadS Char 
+
+    -- * String representations
     , showLitChar       -- :: Char -> ShowS
     , lexLitChar	-- :: ReadS String
-
-    , String
+    , readLitChar       -- :: ReadS Char 
 
      -- Implementation checked wrt. Haskell 98 lib report, 1/99.
     ) where
@@ -42,9 +52,27 @@ module Data.Char
 import GHC.Base
 import GHC.Show
 import GHC.Read (readLitChar, lexLitChar)
+import GHC.Unicode
+import GHC.Num
 #endif
 
 #ifdef __HUGS__
 import Hugs.Char
 #endif
 
+#ifdef __NHC__
+import Prelude
+import Prelude(Char,String)
+import Char
+#endif
+
+-- | Convert a single digit 'Char' to the corresponding 'Int'.  
+-- This function fails unless its argument satisfies 'isHexDigit',
+-- but recognises both upper and lower-case hexadecimal digits
+-- (i.e. @\'0\'@..@\'9\'@, @\'a\'@..@\'f\'@, @\'A\'@..@\'F\'@).
+digitToInt :: Char -> Int
+digitToInt c
+ | isDigit c		=  ord c - ord '0'
+ | c >= 'a' && c <= 'f' =  ord c - ord 'a' + 10
+ | c >= 'A' && c <= 'F' =  ord c - ord 'A' + 10
+ | otherwise	        =  error ("Char.digitToInt: not a digit " ++ show c) -- sigh