Use explicit language extensions & remove extension fields from base.cabal

[ghc-base.git] / Data / Complex.hs

diff --git a/Data/Complex.hs b/Data/Complex.hs
index 3acfa03..9765eda 100644 (file)
--- a/Data/Complex.hs
+++ b/Data/Complex.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE CPP, DeriveDataTypeable #-}
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Data.Complex
@@ -44,6 +46,9 @@ module Data.Complex
 import Prelude
 
 import Data.Typeable
+#ifdef __GLASGOW_HASKELL__
+import Data.Data (Data)
+#endif
 
 #ifdef __HUGS__
 import Hugs.Prelude(Num(fromInt), Fractional(fromDouble))
@@ -62,7 +67,11 @@ infix  6  :+
 data (RealFloat a) => Complex a
   = !a :+ !a    -- ^ forms a complex number from its real and imaginary
                 -- rectangular components.
+# if __GLASGOW_HASKELL__
+        deriving (Eq, Show, Read, Data)
+# else
         deriving (Eq, Show, Read)
+# endif
 
 -- -----------------------------------------------------------------------------
 -- Functions over Complex
@@ -103,9 +112,10 @@ polar z          =  (magnitude z, phase z)
 {-# SPECIALISE magnitude :: Complex Double -> Double #-}
 magnitude :: (RealFloat a) => Complex a -> a
 magnitude (x:+y) =  scaleFloat k
-                     (sqrt ((scaleFloat mk x)^(2::Int) + (scaleFloat mk y)^(2::Int)))
+                     (sqrt (sqr (scaleFloat mk x) + sqr (scaleFloat mk y)))
                     where k  = max (exponent x) (exponent y)
                           mk = - k
+                          sqr z = z * z
 
 -- | The phase of a complex number, in the range @(-'pi', 'pi']@.
 -- If the magnitude is zero, then so is the phase.
@@ -190,4 +200,4 @@ instance  (RealFloat a) => Floating (Complex a) where
 
     asinh z        =  log (z + sqrt (1+z*z))
     acosh z        =  log (z + (z+1) * sqrt ((z-1)/(z+1)))
-    atanh z        =  log ((1+z) / sqrt (1-z*z))
+    atanh z        =  0.5 * log ((1.0+z) / (1.0-z))