On Thu, 2009-02-05 at 20:52 -0600, Gregg Reynolds wrote: > I'm working on a radically different way of looking at IO. Before I > post it and make a fool of myself, I'd appreciate a reality check on > the following points: > > a) Can IO be thought of as a category? I think the answer is yes.
No. At least not in any reasonable way. > b) If it is a category, what are its morphisms? I think the answer > is: it has no morphisms. The morphisms available are natural > transformations or functors, and thus not /in/ the category. > Alternatively: we have no means of directly naming its values, so the > only way we can operate on its values is to use morphisms from the > outside (operating on construction expressions qua morphisms.) N/A > c) All categories with no morphisms ("bereft categories"?) are > isomorphic (to each other). I think yes. No. "Discrete" categories which you seem to be talking about are isomorphic to sets (namely their set of objects). Not all sets are isomorphic. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe