--- /dev/null
+interface Lexer_Buffer where
+add :: Char -> Lexer_Buffer -> Lexer_Buffer
+ {-# ARITY add = 2 #-}
+empty :: Lexer_Buffer
+ {-# ARITY empty = 0 #-}
+flush :: Lexer_Buffer -> Lexer_Buffer
+ {-# ARITY flush = 1 #-}
+len :: Lexer_Buffer -> Int
+ {-# ARITY len = 1 #-}
+to_string :: Lexer_Buffer -> [Char]
+ {-# ARITY to_string = 1 #-}
+data Lexer_Buffer
+