[project @ 2003-08-30 12:26:56 by ross]

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

diff --git a/GHC/Real.lhs b/GHC/Real.lhs
index e1696cc..edee350 100644 (file)
--- a/GHC/Real.lhs
+++ b/GHC/Real.lhs
@@ -26,6 +26,7 @@ import GHC.Show
 
 infixr 8  ^, ^^
 infixl 7  /, `quot`, `rem`, `div`, `mod`
+infixl 7  %
 
 default ()             -- Double isn't available yet, 
                        -- and we shouldn't be using defaults anyway
@@ -153,7 +154,7 @@ numericEnumFromThenTo   :: (Ord a, Fractional a) => a -> a -> a -> [a]
 numericEnumFromThenTo e1 e2 e3 = takeWhile pred (numericEnumFromThen e1 e2)
                                where
                                 mid = (e2 - e1) / 2
-                                pred | e2 > e1   = (<= e3 + mid)
+                                pred | e2 >= e1  = (<= e3 + mid)
                                      | otherwise = (>= e3 + mid)
 \end{code}
 
@@ -171,18 +172,22 @@ instance  Real Int  where
 instance  Integral Int where
     toInteger i = int2Integer i  -- give back a full-blown Integer
 
-    -- Following chks for zero divisor are non-standard (WDP)
-    a `quot` b =  if b /= 0
-                  then a `quotInt` b
-                  else error "Prelude.Integral.quot{Int}: divide by 0"
-    a `rem` b  =  if b /= 0
-                  then a `remInt` b
-                  else error "Prelude.Integral.rem{Int}: divide by 0"
+    a `quot` 0   = divZeroError
+    a `quot` b =  a `quotInt` b
 
-    x `div` y = x `divInt` y
-    x `mod` y = x `modInt` y
+    a `rem` 0   = divZeroError
+    a `rem` b  = a `remInt` b
 
+    a `div` 0   = divZeroError
+    a `div` b   = a `divInt` b
+
+    a `mod` 0   = divZeroError
+    a `mod` b   = a `modInt` b
+
+    a `quotRem` 0 = divZeroError
     a `quotRem` b = a `quotRemInt` b
+
+    a `divMod`  0 = divZeroError
     a `divMod`  b = a `divModInt`  b
 \end{code}
 
@@ -200,14 +205,19 @@ instance  Real Integer  where
 instance  Integral Integer where
     toInteger n             = n
 
+    a `quot` 0 = divZeroError
     n `quot` d = n `quotInteger` d
-    n `rem`  d = n `remInteger`  d
 
-    n `div` d  =  q  where (q,_) = divMod n d
-    n `mod` d  =  r  where (_,r) = divMod n d
+    a `rem` 0 = divZeroError
+    n `rem`  d = n `remInteger`  d
 
+    a `divMod` 0 = divZeroError
     a `divMod` b = a `divModInteger` b
+
+    a `quotRem` 0 = divZeroError
     a `quotRem` b = a `quotRemInteger` b
+
+    -- use the defaults for div & mod
 \end{code}