> > There are various models. One (the state monad model) of them would > desugar this to: > > \world0 -> > let (x, world1) = getLine world0 > world2 = print (x+1) world1 > world3 = print (x+2) world2 > in world3 >
Hi Ertugrul, This state monad model does not really work for IO, since it fails to capture IO's concurrency (with non-deterministic interleaving). I don't know whether/how the "EDSL model" you mention addresses concurrency or FFI. So, maybe these models are models of something other (and much less expressive) than Haskell's IO. Which re-raises Jerzy's question. Regards, - Conal On Mon, Aug 9, 2010 at 10:38 PM, Ertugrul Soeylemez <e...@ertes.de> wrote: > jerzy.karczmarc...@info.unicaen.fr wrote: > > > Alberto G. Corona writes: > > > > > (...) Desugarize the "do" notation, after that, desugarize the >>= > > > and >> operators down to the function call notation and suddenly > > > everithing lost its magic because it becomes clear that a haskell > > > monad is a sugarization of plain functional tricks. > > > > Yep. > > > > But, BTW, could you tell me what was the result of the final > > desugarization and the BASIC sense of the IO monad for you? > > Example: > > do x <- getLine > print (x+1) > print (x+2) > > There are various models. One (the state monad model) of them would > desugar this to: > > \world0 -> > let (x, world1) = getLine world0 > world2 = print (x+1) world1 > world3 = print (x+2) world2 > in world3 > > Another one (the EDSL model, which I personally prefer) would desugar it > to something as simple as this: > > GetLine `BindIO` \x -> > Print (x+1) `BindIO` > const (Print (x+2)) > > I wonder if there are more models for IO. > > > Greets, > Ertugrul > > > -- > nightmare = unsafePerformIO (getWrongWife >>= sex) > http://ertes.de/ > > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe >
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