Getting comonad into base

Sandy Maguire sandy at
Fri Sep 11 19:16:11 UTC 2020

Ollie: It's for giving my own instances. I suspect most of the reasons that
comonads feel uninteresting is that they've been relegated to a
second-class citizen in the ecosystem.

chessai: I'm not proposing the whole package; just the class. I can't
imagine the migration path is any harder than putting an ifdef into the
comonads package.

On Fri, Sep 11, 2020 at 12:06 PM chessai <chessai1996 at> wrote:

> Hi Sandy,
> I think this would be a good candidate for the new Libraries Proposal
> process, modelled after ghc-proposals. See
> I recommend writing a proposal there. In particular, for changes like
> this, one of the things that needs the most thought is the story around a
> migration path.
> Hope this helps.
> Thanks
> On Fri, Sep 11, 2020, 13:55 Sandy Maguire <sandy at> wrote:
>> Hi all,
>> I frequently regret the lack of having the Comonad class in base. Are
>> there any good reasons for its absence? If not, I can get started on a
>> patch.
>> Best,
>> Sandy
>> _______________________________________________
>> Libraries mailing list
>> Libraries at
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