From e0a6623405c50525e79717ed81ed0e75e5325fc8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=93scar=20N=C3=A1jera?= <hi@oscarnajera.com>
Date: Mon, 5 Apr 2021 21:01:33 +0200
Subject: Refactor and hs-lint

---
 ecc.hs | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

(limited to 'ecc.hs')

diff --git a/ecc.hs b/ecc.hs
index 01ef90e..7c485d0 100644
--- a/ecc.hs
+++ b/ecc.hs
@@ -62,26 +62,23 @@ instance Show ECPoint where
 
 validECPoint :: ECPoint -> Bool
 validECPoint Infinity = True
-validECPoint p = (y p)^2 == (x p)^3 + (a p) * (x p) + (b p)
+validECPoint p = y p ^ 2 == x p ^ 3 + a p * x p + b p
 
 add :: ECPoint -> ECPoint -> ECPoint
 add Infinity p = p
 add p Infinity = p
 add p q
-  | (a p) /= (a q) || (b p) /= (b q) = error "point not on same curve"
-  | (x p) == (x q) && (y p) /= (y q) = Infinity
-  | (x p) /= (x q) =
-    let slope = ((y q) - (y p)) / ((x q) - (x p))
-        new_x = slope ^ 2 - (x p) - (x q)
-        new_y = slope * (x p - new_x) - (y p)
-     in ECPoint new_x new_y (a p) (b p)
-  | (x p) == (x q) && (y p) == 0 = Infinity
-  | p == q =
-    let slope = (3 * (x p) ^ 2 + (a p)) / (2 * (y p))
-        new_x = slope ^ 2 - (x p) - (x q)
-        new_y = slope * (x p - new_x) - (y p)
-     in ECPoint new_x new_y (a p) (b p)
+  | a p /= a q || b p /= b q = error "point not on same curve"
+  | x p == x q && y p /= y q = Infinity
+  | x p /= x q = new_point $ (y q - y p) / (x q - x p)
+  | x p == x q && y p == 0 = Infinity
+  | p == q = new_point $ (3 * x p ^ 2 + a p) / (2 * y p)
   | otherwise = error "Unexpected case of points"
+  where
+    new_point slope =
+      let new_x = slope ^ 2 - x p - x q
+          new_y = slope * (x p - new_x) - y p
+       in ECPoint new_x new_y (a p) (b p)
 
 
 cc =
-- 
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