Pre-Proposal: Add Validation somewhere easily accessible

[Joseph Abrahamson]

`Lift` is, but `Errors` should be identical, correct? It appears to work exactly as I would hope in my testing, anyway. The only difference is one further step unwrapping the Constant. Am I missing something major?




Tangentially, I don’t understand why transformers defines its own Constant type, though, given Const in Applicative. At least in transformers 4.0 they use the built-in Eq1 classes and the like.


Joseph

On Mon, Sep 22, 2014 at 7:12 PM, Edward Kmett <ekmett at gmail.com> wrote:

> Lift is rather different than Validation.
> On Mon, Sep 22, 2014 at 3:13 PM, Roman Cheplyaka <roma at ro-che.info> wrote:
>> On 22/09/14 18:43, Andreas Abel wrote:
>> > UPDATE: I found that "Errors e" on
>> >
>> >
>> >
>> https://hackage.haskell.org/package/transformers-0.4.1.0/docs/Control-Applicative-Lift.html
>>
>> Brilliant, thanks a lot! For me, having it in transformers outweighs all
>> the benefits that a separate package may provide (especially a package
>> as heavy as 'errors').
>>
>> Roman
>>
>>
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