[Haskell-cafe] Re: philosophy of Haskell
apfelmus at quantentunnel.de
Wed Aug 18 04:01:18 EDT 2010
Bill Atkins wrote:
> Conal Elliott wrote:
>> And the IO monad is what Jerzy asked about. I'm pointing out that
>> the state monad does not capture concurrency, and the "EDSL model"
>> does not capture FFI. (Really, it depends which "EDSL model". I
>> haven't seen one that can capture FFI. And maybe not concurrency
> So which model captures the way the IO monad works?
This is thoroughly discussed in section 3 of
Simon Peyton Jones.
Tackling the awkward squad: monadic input/output, concurrency,
exceptions, and foreign-language calls in Haskell
In particular, the World -> (a,World) model is unsuitable even without
concurrency because it cannot distinguish
loop, loop' :: IO ()
loop = loop
loop' = putStr "c" >> loop'
I interpret the "EDSL model" to be the operational semantics presented
in the tutorial paper.
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