On 2012/1/1 Ertugrul Söylemez <e...@ertes.de> wrote: > Steve Horne <sh006d3...@blueyonder.co.uk> wrote: > > Of course even the bind operator arguably isn't primitive. We could > > translate to get rid of those too, and see what lies underneath. This > > is where we start seeing functions of type... > > > > World -> (x, World) > > > > Problem - this level of abstraction is hypothetical. It is not part of > > the Haskell language. Haskell specifically defines the IO monad to be > > a black box. > > And that's fine, because IO is an embedded DSL. A better view of IO is > a GADT like: > > data IO :: * -> * where > GetLine :: IO String > PutStrLn :: String -> IO () > ... > > This is still hypothetical, but it shows how even IO is easily > referentially transparent (as long as you don't use unsafe* cheats). >
What?? I see how a definition like this one shows how something else that you call "IO" can be denotative & RT. I don't see how what that conclusion has to do with Haskell's IO. I also wonder whether you're assuming that all of the IO primitives we have in Haskell treat their non-IO arguments denotationally/extensionally, so that there cannot be operations like "isWHNF :: a -> IO Bool". - Conal
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