fix missing EOF token

src/Lox/Expr.hs

@@ -9,4 +9,4 @@ data Expr =
     Unary Token Expr | 
     Binary Expr Token Expr | 
     Grouping Expr
-
+    deriving Show

src/Lox/Parser.hs

@@ -1,5 +1,5 @@
 module Lox.Parser (
-    expression
+    parse
 ) where
 
 import Control.Monad

src/Lox/Scanner.hs

@@ -43,7 +43,7 @@ scanTokensFromSource source = evalState scanTokens (emptyScannerState source)
 scanTokens :: State ScannerState [Token]
 scanTokens = do
     atEnd <- isAtEnd
-    if atEnd then return [] else do
+    if atEnd then return <$> addToken EOF else do
         maybeToken <- scanToken
         case maybeToken of
             Nothing -> scanTokens