Library dilemma / Cofunctor class

ajb at ajb at
Sat Jan 13 19:57:50 EST 2007

G'day all.

Quoting Conal Elliott <conal at>:

> I'm working on a library that includes a Cofunctor instance.  I'd love to
> import whatever standard module has the Cofunctor class, and maybe use some
> Cofunctor combinators.  But, alas, I haven't found such a thing, and I'm
> wondering what to do.

I'd say that the "right" thing to do is first, claim a space in the
module namespace (presumably Control.Cofunctor) and then, release the
world's second-smallest Cabalised library (after hnop).

I am mildly curious as to how you managed to come up with a use for
covariant functors, though.

Andrew Bromage

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