diff --git a/src/Evaluator.hs b/src/Evaluator.hs
index 4d2d982..b5b8bd6 100644
--- a/src/Evaluator.hs
+++ b/src/Evaluator.hs
@@ -8,17 +8,18 @@ type Proc = String
 type Args = [Expr]
 
 eval :: Expr -> Expr
-eval (IntE x)            = IntE x
-eval (VarE v)            = VarE v
-eval (DefinitionE v exp) = NilE
-eval (ProcedureE p args) = apply p args
-eval NilE                = NilE
+eval (IntE x)             = IntE x
+eval (VarE v)             = VarE v
+eval (DefinitionE v exp)  = NilE
+eval (ProcedureE p args)  = apply p args
+eval NilE                 = NilE
 
 apply :: Proc -> Args -> Expr
 apply p args
     | p == "+" = builtinPlus $ map eval args
-
+-- TODO: create a separated file for builtinProcs
 -- TODO: create a BuiltinProc or something like that in data Expr, and make + a builtin proc
+-- TODO: create enviroments
 
 builtinPlus :: [Expr] -> Expr
 builtinPlus [IntE x, IntE y] = IntE $ x + y
diff --git a/src/ExprParser.hs b/src/ExprParser.hs
index 49e40c6..061b41c 100644
--- a/src/ExprParser.hs
+++ b/src/ExprParser.hs
@@ -9,11 +9,14 @@ import ExprType
 parseExpression :: String -> Either ParseError Expr
 parseExpression s = do
   tokns <- parse parseTokens "lexical error" s
-  expr <- parse parseExpressionFromTokens "parsing error" tokns
+  expr <- parse expressionFromTokens "parsing error" tokns
   return expr
 
-parseExpressionFromTokens :: GenParser Token st Expr
-parseExpressionFromTokens = intE <|> try defineE <|> try nilE <|> varE <|> procedureE
+expressionFromTokens :: GenParser Token st Expr
+expressionFromTokens = do
+  expr <- intE <|> try defineE <|> try nilE <|> varE <|> procedureE
+  _ <- eof
+  return expr
 
 intE :: GenParser Token st Expr
 intE = do
@@ -24,7 +27,7 @@ procedureE :: GenParser Token st Expr
 procedureE = do
   _ <- parseLeftParenT
   (VarT p) <- parseVarT
-  args <- many parseExpressionFromTokens
+  args <- many expressionFromTokens
   _ <- parseRightParenT
   return $ ProcedureE p args
 
@@ -43,7 +46,7 @@ defineE = do
   _ <- parseLeftParenT
   _ <- parseDefineT
   (VarT var) <- parseVarT
-  expr <- parseExpressionFromTokens
+  expr <- expressionFromTokens
   _ <- parseRightParenT
   return $ DefinitionE var expr