Yves Parès
Yes but, for instance, every library which provides monad transformers will provides a MTL's MonadTrans instance, not a monadLib's MonadT instance. And since a library hides its types internals, you cannot write the MonadT instances yourself.
For instance, I was planning to translate a little program of mine (which uses quite heavily monad transformers) to monadLib. It uses the packages operational which is based on MTL, and I cannot make myself operational's transformers instances of MonadT.
How would you solve that?
You don't, unfortunately. I would probably use both mtl and monadLib or even rewrite 'operational' to support monadLib.
(btw, I like the fact that monadLib provides IdT ^^ (IdentityT))
Haven't found a use for it though. =) Greets, Ertugrul -- nightmare = unsafePerformIO (getWrongWife >>= sex) http://ertes.de/