Proposal to solve the `EitherT` problem.

Edward A Kmett ekmett at
Wed Aug 14 00:57:22 CEST 2013

I look forward to finding out the new name for MaybeT then. ;)

Sent from my iPhone

On Aug 13, 2013, at 1:25 PM, Ross Paterson <R.Paterson at> wrote:

> On Tue, Aug 13, 2013 at 10:30:23AM -0400, Edward Kmett wrote:
>> An argument against just randomly bikeshedding the name it is there
>> are a lot of packages out there currently transitively depending on
>> the existing either package, due to the popularity of Tekmo's errors
>> package and the fact that it has been picked up by snap. So half of
>> the web-apps in the ecosystem depend on this type transitively.
> Fortunately it seems that EitherT is only used by the following packages:
>        citation-resolve coroutine-object CSPM-Frontend errors
>        happstack-heist hoodle-core hoodle-parser katt pdf-toolbox-core
>        pianola restricted-workers terminfo-hs
> Moreover adding a new module and type means people can switch over an
> extended timescale.  Thus I think internal consistency within transformers
> outweighs compatibility with the existing EitherT in this case.
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