Re: Pre-Proposal: Add Validation somewhere easily accessible

There was some discussion of retiring Constant, as it is mostly unused, and Const has supplanted it in common usage. It didn't happen with this last release of transformers. -Edward On Mon, Sep 22, 2014 at 7:27 PM, Joseph Abrahamson wrote:

`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 wrote:

...

Lift is rather different than Validation.

On Mon, Sep 22, 2014 at 3:13 PM, Roman Cheplyaka wrote:

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On 22/09/14 18:43, Andreas Abel wrote:

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UPDATE: I found that "Errors e" on

https://hackage.haskell.org/package/transformers-0.4.1.0/docs/Control-Applic...

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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