Diff -> Xor on lists

README.md

@@ -4,7 +4,8 @@
 This implementation is more generic that this [definition on
 wikipedia](https://en.wikipedia.org/wiki/Majority_judgment), even if it
 reuses the same application example: if two ballots have the same score,
-then diff of vote is computed to compute a new score.
+then xor of votes is computed to then compute a new score on these same
+ballots.
 
 Not really tested yet, feedbacks welcome, just to better understand how
 it works.

src/Lib.hs

@@ -87,20 +87,20 @@ instance Ord Ballot where
       False -> compare (score v1) (score v2)
       True  -> compare (score v1') (score v2')
             where
-              (v1', v2') = diff (v1, v2)
+              (v1', v2') = xor (v1, v2)
 
 score :: [Vote] -> Maybe Rational
 score = median . map voteToRational
 
 ------------------------------------------------------------------------
 
-diff :: Ord a => ([a],[a]) -> ([a],[a])
-diff (m1,m2) = (fromMap m1', fromMap m2')
+xor :: Ord a => ([a],[a]) -> ([a],[a])
+xor (m1,m2) = (fromMap m1', fromMap m2')
   where
-    (m1', m2') = diffMap (toMap m1, toMap m2)
+    (m1', m2') = xorMap (toMap m1, toMap m2)
 
-diffMap :: Ord a => (Map a Int, Map a Int) -> (Map a Int, Map a Int)
-diffMap (m1,m2) = (m1',m2')
+xorMap :: Ord a => (Map a Int, Map a Int) -> (Map a Int, Map a Int)
+xorMap (m1,m2) = (m1',m2')
   where
     m1' = DM.unionWith outer m1 m13
     m2' = DM.unionWith outer m2 m23