On Fri, Aug 09, 2013 at 12:38:45AM +0700, Kim-Ee Yeoh wrote: > On Thu, Aug 8, 2013 at 11:05 PM, Tom Ellis > <tom-lists-haskell-cafe-2...@jaguarpaw.co.uk> wrote: > > On Thu, Aug 08, 2013 at 03:38:41PM +0200, Jerzy Karczmarczuk wrote: > > > >One could simply implement IO as a free monad > > > Interesting. I wonder how. > > > > See [1] for an explanation of free monads in general. For IO in > > particular, > > define a functor > > > > data IOF a = GetChar (Char -> a) | PutChar Char a | ... > > > > with constructors for all elementary IO operations. > > If I understand correctly, you're proposing equality of (IO a) based on the > AST of imperatives, similar to what comes out of GCC's front-end for C [1].
I'm not proposing it. I'm just pointing out it could be done, as a challenge to Jerzy's assertion that "In fact, you can do almost nothing with [values of type IO ()]". However, I may have misunderstood Jerzy's point anyway. Tom _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
