diff --git a/src/Lish/Core.hs b/src/Lish/Core.hs
index a41f9d9..cbad30b 100644
--- a/src/Lish/Core.hs
+++ b/src/Lish/Core.hs
@@ -45,7 +45,7 @@ mainLoop env = do
     Just "exit" -> outputStrLn "bye bye!"
     Just "logout" -> outputStrLn "bye bye!"
     Just line -> do
-      newenv <- eval env (parseCmd ("(" <> line <> ")"))
+      newenv <- eval env (parseCmd ("(" <> toS line <> ")"))
       mainLoop newenv
 
 -- | Eval the reduced form
diff --git a/src/Lish/InternalCommands.hs b/src/Lish/InternalCommands.hs
index abc1da7..4846bd4 100644
--- a/src/Lish/InternalCommands.hs
+++ b/src/Lish/InternalCommands.hs
@@ -90,6 +90,19 @@ atom ((Atom a):[]) = return $ Atom a
 atom ((Str s):[])  = return $ Atom s
 atom _             = evalErr "atom need an atom or a string"
 
+-- | Numbers Ops
+binop :: (Integer -> Integer -> Integer) -> Command
+binop f ((Num x):(Num y):[]) = return $ Num (f x y)
+binop _ _ = evalErr "binary operator needs two numbers"
+
+bbinop :: (Bool -> Bool -> Bool) -> Command
+bbinop f ((Bool x):(Bool y):[]) = return $ Bool (f x y)
+bbinop _ _ = evalErr "boolean binary operator need two booleans arguments"
+
+lnot :: Command
+lnot ((Bool x):[]) = return ( Bool (not x))
+lnot _ = evalErr "not need a boolean"
+
 toWaitingStream :: Command
 toWaitingStream (Stream (Just h) :[]) = return (WaitingStream (Just h))
 toWaitingStream _                     = return Void
@@ -106,6 +119,16 @@ internalCommands = [ ("prn", prn)
                    , ("$",getenv)
                    , ("str",str)
                    , ("atom",atom)
+                   -- binary operators
+                   , ("+",binop (+))
+                   , ("-",binop (-))
+                   , ("*",binop (*))
+                   , ("/",binop div)
+                   , ("^",binop (^))
+                   -- boolean bin ops
+                   , ("and", bbinop (&&))
+                   , ("or", bbinop (||))
+                   , ("not", lnot)
                    ] & Map.fromList
 
 lookup :: Text -> Maybe Command
diff --git a/src/Lish/Parser.hs b/src/Lish/Parser.hs
index 5c72e8b..a3554eb 100644
--- a/src/Lish/Parser.hs
+++ b/src/Lish/Parser.hs
@@ -5,36 +5,45 @@ module Lish.Parser
   (parseCmd)
   where
 
-import           Prelude     (String)
-import           Protolude   hiding (for, many, (<|>))
+import           Protolude   hiding (for, many, (<|>), optional)
 import           Text.Parsec
+import           Text.Parsec.Text
 
 import           Lish.Types
 
-parseCmd :: String -> Either ParseError SExp
+parseCmd :: Text -> Either ParseError SExp
 parseCmd = parse parseExpr "S-Expr"
 
-parseExpr :: Parsec String () SExp
+parseExpr :: Parser SExp
 parseExpr = parseLambda
             <|> parseList
+            <|> parseBool
+            <|> parseNumber
             <|> parseAtom
             <|> parseString
 
-parseAtom :: Parsec String () SExp
+parseNumber :: Parser SExp
+parseNumber = (Num . fromMaybe 0 . readMaybe) <$> many1 digit
+
+parseBool :: Parser SExp
+parseBool = Bool <$> ((string "true" >> return True)
+                      <|> (string "false" >> return False))
+
+parseAtom :: Parser SExp
 parseAtom = Atom <$> do frst <- (noneOf " \t()[]\"")
                         rest <- many (noneOf " \t()[]")
                         return $ toS (frst:rest)
 
-parseString :: Parsec String () SExp
+parseString :: Parser SExp
 parseString = (Str . toS) <$> between (char '"')
                               (char '"')
                               (many (noneOf "\""))
 
-parseSExps :: Parsec String () [SExp]
+parseSExps :: Parser [SExp]
 parseSExps = sepEndBy parseExpr spaces
 
-parseLambda :: Parsec String () SExp
+parseLambda :: Parser SExp
 parseLambda = Lambda <$> between (char '(') (char ')') parseSExps
 
-parseList :: Parsec String () SExp
+parseList :: Parser SExp
 parseList = List <$> between (char '[') (char ']') parseSExps
diff --git a/src/Lish/Types.hs b/src/Lish/Types.hs
index 16a5116..d94104f 100644
--- a/src/Lish/Types.hs
+++ b/src/Lish/Types.hs
@@ -16,12 +16,18 @@ import           GHC.IO.Handle   (Handle)
 import           GHC.Show        (Show (..))
 import           Protolude       hiding (show)
 
-data SExp = Lambda [SExp]
-          | Atom Text
-          | List [SExp]
+data SExp = Atom Text
+          | Num Integer
+          | Bool Bool
           | Str Text
+          | List [SExp]
+          | Lambda [SExp]
           | Void
           -- only exists during evaluation
+          | Fn { params :: [Text]
+               , body :: [SExp]
+               , closure :: Env
+               }
           | Stream CmdStream
           | WaitingStream CmdStream
 
@@ -29,11 +35,14 @@ instance Show SExp where
   show = toS . repr
 
 repr :: SExp -> Text
-repr (Atom s)        = s
-repr (Str s)         = "\"" <> toS s <> "\""
-repr (Lambda sexprs) = "(λ." <> (Text.intercalate " " (map repr sexprs)) <> ")"
-repr (List sexprs)   = "[" <> (Text.intercalate " " (map repr sexprs)) <> "]"
-repr Void            = "ε"
+repr (Atom s)          = s
+repr (Num n)           = toS $ show n
+repr (Bool b)          = if b then "true" else "false"
+repr (Str s)           = "\"" <> toS s <> "\""
+repr (List sexprs)     = "[" <> (Text.intercalate " " (map repr sexprs)) <> "]"
+repr (Lambda sexprs)   = "(" <> (Text.intercalate " " (map repr sexprs)) <> ")"
+repr Void              = "ε"
+repr (Fn p _ _)        = "(λ" <> (Text.intercalate "." p) <> ". ... )"
 repr (Stream _)        = "<stream>"
 repr (WaitingStream _) = "<w-stream>"