[Haskell-cafe] morphisms in IO

Gregg Reynolds dev at mobileink.com
Thu Feb 5 21:52:07 EST 2009

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.

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.)

c)  All categories with no morphisms ("bereft categories"?) are
isomorphic (to each other).  I think yes.



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