Re: Why is there no Foldable instance for Either?

I actually kind of like Const as it matches 'const' - though I'm not sure how similar they really are in theory. On 12 Jun 2013 20:39, "Edward Kmett" wrote:

The main concern I would have is that Const actually seems to be in use everywhere, while Constant is more or less unused by dint of the fact that Const comes into scope with Control.Applicative, so many more people are aware of it.

-Edward

On Wed, Jun 12, 2013 at 1:26 PM, Ross Paterson wrote:

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On Wed, Jun 12, 2013 at 5:10 AM, Shachaf Ben-Kiki wrote: Just to make sure this isn't slipping through the cracks -- is

On Wed, Jun 12, 2013 at 11:01:15AM -0400, Edward Kmett wrote: there a

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particular reason not to add the instance for (Const r)? It was brought up in the last discussion and it has one obviously-correct definition. It's a useful instance.

No reason at all other than an annoying major version bump in

transformers.

Constant in transformers already has these instances, but Const in base doesn't. Otherwise they're the same (and both of them are my fault). One of them should go -- I'm in favour of keeping the full name.

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