Proposal: merge either into transformers

[Ross Paterson]

On Sat, Apr 26, 2014 at 09:16:57AM +0300, Roman Cheplyaka wrote:
> * Ross Paterson <R.Paterson at city.ac.uk> [2014-04-26 01:21:09+0100]
> > Instead of EitherT, the next version will deprecate ErrorT in favour
> > of a transformer ExceptT with base monad Except.  The idea is to have
> > analogous transformers and monads
> > 
> > 	ExceptT : Except : Either
> > 	WriterT : Writer : (,)
> > 	ReaderT : Reader : (->)
> 
> Great! When do you plan to make a release?

Let's say Wednesday, if no-one notices a major problem.

> > Pre-release docs are here:
> > 
> > 	http://code.haskell.org/~ross/transformers/dist/doc/html/transformers/
> 
> The docs for Control.Monad.Trans.Writer.Strict say:
> 
>   >  Although the output is built strictly, it is not possible to achieve linear
>   >  space behaviour with this transformer: for that, use
>   >  Control.Monad.Trans.State.Strict instead.
> 
> I think it should be "constant", not "linear".

Indeed -- thanks for catching that.  I wonder whether the strict writer
is of any use at all.