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