Merge either into transformers

[Yitzchak Gale]

Glad to hear.

The next step was supposed to be moving a few instances out of
the either library and deprecating that library. Is that no longer planned?

Whether or not it will be deprecated, a prominent note about this
really should be added to the package description of the either
library.

And a note should be added to the module description of
Control.Monad.Trans.Except that throwing exceptions is only
one of many uses for this monad. I frequently use (the old
either library version of) this monad for complex conditional
logic and early exit from computations, at least as often as
I use it for throwing exceptions.

Thanks,
Yitz


On Mon, Dec 29, 2014 at 12:29 AM, Roman Cheplyaka <roma at ro-che.info> wrote:
> It is already merged (under the name of ExceptT).
>
> On 28/12/14 23:14, Yitzchak Gale wrote:
>> Roman Cheplyaka wrote in February 2014:
>>>> I proposed to merge either into transformers more than a year ago[1],
>>>> and everyone seemed to agree. Could you please do it?
>>>>
>>>> [1]: http://www.haskell.org/pipermail/libraries/2012-December/019027.html
>>
>> Ross Paterson responded:
>>> Not everyone agreed when we discussed this last August.  My proposal then
>>> was to introduce a new constructor ExceptT on the same pattern as ReaderT,
>>> etc, and to deprecate ErrorT, and that's what I intend to include in the
>>> next major release, after GHC 7.8 comes out.
>>
>> First of all, GHC 7.8 is well past. Now we are well into the 7.10 zone.
>>
>> I re-read the original thread and did not find anyone who disagreed with
>> this, so I'm not sure what you mean by that.
>>
>> I also didn't find any mention of ExceptT there. The discussion was about
>> merging the either library into transformers as is, with the bits that
>> are problematic due to non-base dependencies written out by hand
>> where possible or else omitted.
>>
>> That said, I think everyone will support you, without bikeshedding, if
>> you decide to change any of the names and/or deprecate ErrorT.
>>
>> Thanks,
>> Yitz
>>
>