proposed change to transformers package

Ross Paterson ross at
Wed Mar 24 18:28:09 EDT 2010

On Thu, Mar 25, 2010 at 08:13:37AM +1100, Erik de Castro Lopo wrote:
> Ross Paterson wrote:
> > I propose to rename some of the modules in the transformers package so
> > that it no longer conflicts with the mtl package:
> I thought the plan was to replace mtl with transformers.
> If that was the plan wouldn't it be better to actually kill off
> mtl so it doesn't hang around for years to come?

The aim is still to split the concrete monad transformers from the
multi-parameter classes with functional dependencies.  Last year
we proposed replacing mtl with two packages representing the split
(transformers and monads-fd) in a big bang, but there was concern about
the degree of change.  This proposal allows transformers to co-exist
with mtl, but also makes monads-fd (depending on transformers) closer
to being a plugin replacement for mtl (but still not completely one).
I hope to propose such a replacement in the future.

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