--- /dev/null
+interface Source_Position where
+make :: Int -> Int -> Source_Position
+ {-# ARITY make = 2 #-}
+next_line :: Source_Position -> Source_Position
+ {-# ARITY next_line = 1 #-}
+shift_column :: Source_Position -> Int -> Source_Position
+ {-# ARITY shift_column = 2 #-}
+show_pos :: Source_Position -> [Char] -> [Char]
+ {-# ARITY show_pos = 1 #-}
+start :: Source_Position
+ {-# ARITY start = 0 #-}
+data Source_Position = Source_Position Int Int
+instance Text Source_Position
+ {-# ARITY readsPrec = 0 #-}
+ {-# ARITY showsPrec = 2 #-}
+ {-# ARITY readList = 0 #-}
+ {-# ARITY showList = 0 #-}
+