hi, Georg Martius wrote:
Now I have also functions to map from (a, String) -> (a,String). I could write:
modifyT :: ((a, String) -> (a, String)) -> a -> State String a modifyT trans a = do str <- get let (a', str') = trans (a, str) put str' return a'
f :: State String () f = do put "hallo" modify strTrans i <- modifyT strIntTrans 4 -- strIntTrans :: (Int, String) -> (Int, String) i' <- modifyT strIntTrans i ...
But this is obviously awkward. How can I stick two Monads in each other? I could't figure out how to use StateT. Any help would be appreciated.
Thanks! Georg
could you be a little more specific on what you are trying to do? what do you mean by sticking two monads in each other, do you want to have two state componenets, or perhaps work with computations that manipulate state, but can also raise exceptions? -iavor -- ================================================== | Iavor S. Diatchki, Ph.D. student | | Department of Computer Science and Engineering | | School of OGI at OHSU | | http://www.cse.ogi.edu/~diatchki | ==================================================