add PBTs for arithmetic operators

 - commutativity of addition
 - commutativity of multiplication

1 files changed, 0 insertions, 3 deletions

diff --git a/src/Error/Base.hs b/src/Error/Base.hs
index b6ae9a3..509377b 100644
--- a/src/Error/Base.hs
+++ b/src/Error/Base.hs
@@ -5,12 +5,9 @@ module Error.Base (
              ) where
 
 import           Control.Monad.Except
-import           Data.List                     (intercalate, nub)
 import           Parser
 import           Text.Parsec
 import           Text.Parsec.Error
-import           Text.Parsec.Pos
-import           Text.Parsec.String            (Parser)
 import           Text.ParserCombinators.Parsec
 
 data LispError = Parse ParseError