-----------------------------------------------------------------------------
-- trace :: String -> a -> a	Print the string and return the given value
--
-- This file brings in just enough of the lambda var primitives to implement
-- a version of the impure hbc debugging function `trace'.  Note that, this
-- can only be used in conjunction with a version of the Gofer interpreter
-- that has been compiled to include these primitives.  See the file
-- lambdaVr for more details.
-----------------------------------------------------------------------------

primitive primLvPure   "primLvPure"     :: Proc a -> a
primitive primLvReturn "primLvReturn"   :: a -> Proc a
primitive primLvBind   "primLvBind"     :: Proc a -> (a -> Proc b) -> Proc b
primitive primLvPutch  "primLvPutchar"  :: Char -> Proc ()

trace    :: String -> a -> a
trace s a = primLvPure (f s)
            where f []     = primLvReturn a
                  f (x:xs) = primLvBind (primLvPutch x) (\_ -> f xs)

-- End of trace --------------------------------------------------------------