X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=Data%2FComplex.hs;h=369250149267dddf662073c0b77fdedea3ef62b2;hb=8073392a94dc5ab198e4758d6738a0c7f5ed68cf;hp=6ebbfcbaeb8ae33e105c5bf5d240360519c6ae88;hpb=9875b3cf1ada084cfa3e6c516b11e946f1d6234e;p=ghc-base.git

diff --git a/Data/Complex.hs b/Data/Complex.hs
index 6ebbfcb..3692501 100644
--- a/Data/Complex.hs
+++ b/Data/Complex.hs
@@ -1,3 +1,8 @@
+{-# LANGUAGE CPP, DeriveDataTypeable #-}
+#ifdef __GLASGOW_HASKELL__
+{-# LANGUAGE StandaloneDeriving #-}
+#endif
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Data.Complex
@@ -62,10 +67,14 @@ 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__
+        deriving (Eq, Show, Read, Data)
+# else
         deriving (Eq, Show, Read)
+# endif
 
 -- -----------------------------------------------------------------------------
 -- Functions over Complex
@@ -194,4 +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))