1 files changed, 18 insertions, 1 deletions

diff --git a/src/Operators.hs b/src/Operators.hs
index beb6364..e607250 100644
--- a/src/Operators.hs
+++ b/src/Operators.hs
@@ -19,6 +19,7 @@ primitives =
     , ("<=", comparator (<=))
     , ("=", comparator (==))
     , ("!=", comparator (/=))
+    , ("not", unaryBool not)
     ]
 
 data LispNumber = I Integer
@@ -38,7 +39,9 @@ instance Num LispNumber where
     (F a) * (F b) = F $ a * b
 
 instance Fractional LispNumber where
-    (I a) / (I b) = I $ a `div` b
+    (I a) / (I b) = F $ fromIntegral a / fromIntegral b
+    (F a) / (I b) = F $ a / fromIntegral b
+    (I a) / (F b) = F $ fromIntegral a / b
     (F a) / (F b) = F $ a / b
 
 arithmetic :: (LispNumber -> LispNumber -> LispNumber) -> [Expr] -> LispResult Expr
@@ -55,6 +58,16 @@ comparator op args
         as <- mapM unwrapNum args
         return . BoolLiteral . all (== True) $ zipWith op as (tail as)
 
+unaryBool :: (Bool -> Bool) -> [Expr] -> LispResult Expr
+unaryBool op args
+  | length args /= 1 = throwError $ ArgCount 1 args
+  | otherwise = BoolLiteral . op <$> unwrapBool (head args)
+
+naryBool :: (Bool -> Bool -> Bool) -> [Expr] -> LispResult Expr
+naryBool op args
+  | length args < 2 = throwError $ ArgCount 2 args
+
+
 unwrapNum :: Expr -> LispResult LispNumber
 unwrapNum (IntLiteral n)   =  return $ I n
 unwrapNum (FloatLiteral n) =  return $ F n
@@ -63,3 +76,7 @@ unwrapNum x                = throwError $ TypeMismatch "number" x
 wrapNum :: LispNumber -> Expr
 wrapNum (I n) = IntLiteral n
 wrapNum (F n) = FloatLiteral n
+
+unwrapBool :: Expr -> LispResult Bool
+unwrapBool (BoolLiteral s) = return s
+unwrapBool x               = throwError $ TypeMismatch "boolean" x