X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FRealFunction.hs;h=cf98029a5f4948d71375ca0e8c188e19a2d39527;hb=c832bb3ac428a0d96759d9c82e9547d3acf4353d;hp=6a557a9f0f4d4bdb33df42485d84ae02e57cabe5;hpb=58cf11569acb270995d2de924dda03ef526647e2;p=spline3.git

diff --git a/src/RealFunction.hs b/src/RealFunction.hs
index 6a557a9..cf98029 100644
--- a/src/RealFunction.hs
+++ b/src/RealFunction.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE TypeSynonymInstances #-}
+{-# LANGUAGE FlexibleInstances #-}
 
 module RealFunction
 where
@@ -11,13 +11,13 @@ type RealFunction a = (a -> Double)
 instance Show (RealFunction a) where
     -- | There is nothing of value that we can display about a
     --   function, so simply print its type.
-    show _ = "RealFunction"
+    show _ = "<RealFunction>"
 
 
 -- | An 'Eq' instance is required to be a 'Num' instance.
 instance Eq (RealFunction a) where
     -- | Nothing else makes sense here; always return 'False'.
-    _ == _ = False
+    _ == _ = error "You can't compare functions for equality."
 
 
 -- | The 'Num' instance for RealFunction allows us to perform