transformers versus mtl

[Ross Paterson]

On Sun, Mar 22, 2009 at 06:31:08AM -0000, Sittampalam, Ganesh wrote:
> Essentially we have the choice of producing full compatibility
> by keeping the separate type in mtl, in which case State from mtl
> is not State from transformers, or partial compatibility by
> re-exporting the transformers one.

Yes, we must choose between full compatibility with mtl and full
compatibility with transformers.  A quick implementation of the former is

http://code.haskell.org/~ross/mtl-compat/

The separate versions of State etc are present, but deprecated.