Sorry, I still have semigroupoids on my mind. There's no renaming like with Foldable1, so yes the migration path is not more complicated than what you say. I still think a proposal is worthwhile because many people (including myself) fail to see motivation for comonads in every day programming. The fact that Ollie, an experienced haskell programmer, also shares this sentiment makes me more certain that people need motivating. I think a proposal is a good way to do that. On Fri, Sep 11, 2020, 14:16 Sandy Maguire wrote:

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 wrote:

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Hi Sandy,

I think this would be a good candidate for the new Libraries Proposal process, modelled after ghc-proposals. See https://github.com/haskell-core/core-libraries-proposals

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 wrote:

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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@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries