Remove datatype contexts from base

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

diff --git a/Data/Complex.hs b/Data/Complex.hs
index bbc8a07..3692501 100644 (file)
--- a/Data/Complex.hs
+++ b/Data/Complex.hs
@@ -1,3 +1,8 @@
+{-# LANGUAGE CPP, DeriveDataTypeable #-}
+#ifdef __GLASGOW_HASKELL__
+{-# LANGUAGE StandaloneDeriving #-}
+#endif
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Data.Complex
@@ -62,7 +67,7 @@ infix  6  :+
 -- For a complex number @z@, @'abs' z@ is a number with the magnitude of @z@,
 -- but oriented in the positive real direction, whereas @'signum' z@
 -- has the phase of @z@, but unit magnitude.
-data (RealFloat a) => Complex a
+data Complex a
   = !a :+ !a    -- ^ forms a complex number from its real and imaginary
                 -- rectangular components.
 # if __GLASGOW_HASKELL__
@@ -198,4 +203,4 @@ 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))