[Haskell-cafe] Why no IO transformer monad?

Henning Sato von Rosen henning.von.rosen at gmail.com
Sat Dec 18 12:30:45 EST 2004

Hi all!

For each basic monad there seems to be a corresponding transformer,
e.g.  'StateT' for 'State' and so on.

I guess the reason lies in the fact that if there were an IO
Transformer monad, one might run it and get the 'Universe' out of the
IO monad.

But, I am working on understanding IO magic, on a much more concrete
level, so I am am looking for a really good explanation of the above.
(And the IO monad in general.)



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