in stage1, we should get isPrint and isUpper from Compat.Unicode, not Data.Char

[ghc-hetmet.git] / ghc / compiler / parser / LexCore.hs

diff --git a/ghc/compiler/parser/LexCore.hs b/ghc/compiler/parser/LexCore.hs
index 04e1060..1a545a3 100644 (file)
--- a/ghc/compiler/parser/LexCore.hs
+++ b/ghc/compiler/parser/LexCore.hs
@@ -3,7 +3,7 @@ module LexCore where
 import ParserCoreUtils
 import Ratio
 import Char
-import Numeric( readFloat )
+import qualified Numeric( readFloat, readDec )
 
 isNameChar c = isAlpha c || isDigit c || (c == '_') || (c == '\'') 
 isKeywordChar c = isAlpha c || (c == '_') 
@@ -66,7 +66,7 @@ lexNum cont cs =
  where f sgn cs = 
          case span isDigit cs of
           (digits,'.':c:rest) 
-               | isDigit c -> cont (TKrational r) rest'
+               | isDigit c -> cont (TKrational (fromInteger sgn * r)) rest'
                where ((r,rest'):_) = readFloat (digits ++ ('.':c:rest))
                -- When reading a floating-point number, which is
                -- a bit complicated, use the Haskell 98 library function
@@ -92,3 +92,39 @@ lexKeyword cont cs =
       ("_",rest) -> cont TKwild rest
       _ -> failP "invalid keyword" ('%':cs) 
 
+
+#if __GLASGOW_HASKELL__ >= 504
+-- The readFloat in the Numeric library will do the job
+
+readFloat :: (RealFrac a) => ReadS a
+readFloat = Numeric.readFloat
+
+#else
+-- Haskell 98's Numeric.readFloat used to have a bogusly restricted signature
+-- so it was incapable of reading a rational.  
+-- So for GHCs that have that old bogus library, here is the code, written out longhand.
+
+readFloat r    = [(fromRational ((n%1)*10^^(k-d)),t) | (n,d,s) <- readFix r,
+                                                       (k,t)   <- readExp s] ++
+                 [ (0/0, t) | ("NaN",t)      <- lex r] ++
+                 [ (1/0, t) | ("Infinity",t) <- lex r]
+               where 
+                 readFix r = [(read (ds++ds'), length ds', t)
+                             | (ds,d) <- lexDigits r,
+                               (ds',t) <- lexFrac d ]
+               
+                 lexFrac ('.':ds) = lexDigits ds
+                 lexFrac s        = [("",s)]        
+                 
+                 readExp (e:s) | e `elem` "eE" = readExp' s
+                 readExp s                     = [(0,s)]
+                 
+                 readExp' ('-':s) = [(-k,t) | (k,t) <- Numeric.readDec s]
+                 readExp' ('+':s) = Numeric.readDec s
+                 readExp' s       = Numeric.readDec s
+
+lexDigits :: ReadS String 
+lexDigits s =  case span isDigit s of
+                (cs,s') | not (null cs) -> [(cs,s')]
+                otherwise               -> []
+#endif