29 Dec
2010
29 Dec
'10
5:34 p.m.
2010/12/30 David Leimbach
Reader Writer State is commonly needed in big applications so transformers provides one for us: http://hackage.haskell.org/packages/archive/transformers/0.2.2.0/doc/html/Co... Pretty cool stuff if you ask me. I often wondered about the correct stacking order of Monad transformers, or how often it mattered.
Thanks, it is very cool indeed! And it turns out that it's not simply kind of the "type RWST r w s m a = ReaderT r WriterT w StateT s m a", it has completely independent implementation. It is done in one layer, so no lifts for tell, get, put, modify and so on.