[FIX] Error Messages.

src/Lib.hs

@@ -78,23 +78,28 @@ ballots4 = [ Ballot "Fascism"   (ratedAs [(90, Excellent)])
 -- | Select the Winner
 -- TODO: sortBy and intersect according to Result
 -- sort then take While equality
-winnerIs :: MajorityJudgment -> Either Text (Maybe Ballot)
+winnerIs :: MajorityJudgment -> Either Unfair (Maybe Ballot)
 winnerIs mj = case isFair mj of
-                False -> Left  "Unfair Election"
-                True  -> Right $ (headMay . reverse . sort) mj
+                Just unfair -> Left  unfair
+                Nothing     -> Right $ (headMay . reverse . sort) mj
 
+data Unfair = NoChoice | NoRepresentativity
+  deriving (Show)
 
 -- | Asserts is the Election with Majority Judgment is Fair
 -- e.g. methodology of vote is respected to collect the ballots
 -- Number of vote per Ballot must be equal
 -- add an axiom: must not be Poor at least by one voter ?
 -- TODO: be more explicit why election is not fair
-isFair :: MajorityJudgment -> Bool
-isFair mj = length vs > 2 && all (== head vs) vs
+isFair :: MajorityJudgment -> Maybe Unfair
+isFair mj = case length vs < 2 of
+  True -> Just NoChoice
+  False -> case all (== head vs) vs of
+    False -> Just NoRepresentativity
+    True  -> Nothing
   where
     vs = map (length . votes) mj
 
-data Unfair = NoChoice | NoRepresentativity
 
 
 instance Eq Ballot where