cabal

only doing this because Data.Set is not in the stdlib

Logic/Statement.hs

@@ -1,30 +0,0 @@
-module Logic.Statement where
-
-import Data.Set (singleton, union, toAscList)
-
-data Statement
-  = Atom String
-  | Not Statement
-  | And Statement Statement
-  | Or Statement Statement
-  | Implies Statement Statement
-  | Iff Statement Statement
-  deriving (Eq, Ord, Show)
-
-atoms :: Statement -> [String]
-atoms = toAscList . mkSet
-  where
-    mkSet (Atom key)      = singleton key
-    mkSet (Not s)         = mkSet s
-    mkSet (And s1 s2)     = union (mkSet s1) (mkSet s2)
-    mkSet (Or s1 s2)      = union (mkSet s1) (mkSet s2)
-    mkSet (Implies s1 s2) = union (mkSet s1) (mkSet s2)
-    mkSet (Iff s1 s2)     = union (mkSet s1) (mkSet s2)
-
-substatements :: Statement -> [Statement]
-substatements s@(Atom _) = [s]
-substatements s@(Not s1) = s:(substatements s1)
-substatements s@(And s1 s2)     = (s:) $ substatements s1 ++ substatements s2
-substatements s@(Or s1 s2)      = (s:) $ substatements s1 ++ substatements s2
-substatements s@(Implies s1 s2) = (s:) $ substatements s1 ++ substatements s2
-substatements s@(Iff s1 s2)     = (s:) $ substatements s1 ++ substatements s2