Overlapping show

1 files changed, 6 insertions, 1 deletions

diff --git a/ecc.hs b/ecc.hs
index e639e3a..83a9fb1 100644
--- a/ecc.hs
+++ b/ecc.hs
@@ -57,7 +57,12 @@ data ECPoint a
       }
   deriving (Eq)
 
-instance KnownNat n => Show (ECPoint (FieldElement n)) where
+
+instance {-# OVERLAPPABLE #-} (PrintfArg a, Num a) => Show (ECPoint a) where
+  show Infinity = "ECPoint(Infinity)"
+  show p        =  printf "ECPoint(%f, %f)_%f_%f" (x p) (y p) (a p) (b p)
+
+instance {-# OVERLAPPING  #-} KnownNat n => Show (ECPoint (FieldElement n)) where
   show Infinity = "ECPoint(Infinity)"
   show p
     | n == (2 ^ 256 - 2 ^ 32 - 977) = "S256Point" ++ points