From: haskell-cafe-bounces@haskell.org [mailto:haskell-cafe-bounces@haskell.org] On Behalf Of peterv
However, one thing which I find annoying is that a "classic pure" function cannot evaluate an IO function unless you use unsafePerformIO; one must "promote" (?demote) the pure function into the IO monad.
That's just a property of the IO monad, rather than monads in general: http://www.haskell.org/all_about_monads/html/laws.html#nowayout
Any ways of "promoting" such a pure function into the monadic one automatically? I tried playing with "liftM", without succes.
This is where Claus plugs HaRe :-) (although liftM + friends is normally what one uses). You might find this relevant: http://www.cs.kent.ac.uk/projects/refactor-fp/catalogue/Monadification1. html Some people (but I'm not sure who) probably write most of their Haskell code in a monadic style, so as to make conversion between various monads less painful. It's still pure... Alistair ***************************************************************** Confidentiality Note: The information contained in this message, and any attachments, may contain confidential and/or privileged material. It is intended solely for the person(s) or entity to which it is addressed. Any review, retransmission, dissemination, or taking of any action in reliance upon this information by persons or entities other than the intended recipient(s) is prohibited. If you received this in error, please contact the sender and delete the material from any computer. *****************************************************************