Haskell Platform call for consensus: add transformers and
revise the mtl package to depend on it
ross at soi.city.ac.uk
Thu Nov 4 08:11:18 EDT 2010
On Wed, Nov 03, 2010 at 12:44:33PM -0400, Brent Yorgey wrote:
> As an experience report, I just ported the diagrams
> package to mtl-2. As a matter of fact it did require some changes,
> because one place in the code explicitly used the Cont constructor
> which had to be changed to ContT (and some Identity wrapping and
> unwrapping added). But it wasn't a big deal and it works fine now.
The transformers package has (in Control.Monad.Trans.Cont) a function
cont :: ((a -> r) -> r) -> Cont r a
to serve as a plugin replacement for the Cont constructor (and similarly
for the other base monads that are now type synonyms).
One could argue that these should be re-exported by mtl-2, but I was
aiming for maximum compatibility.
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