MTL vs Transformers. Any status update?

Duncan Coutts duncan.coutts at
Sun Nov 29 14:48:56 EST 2009

On Sun, 2009-11-29 at 21:08 +0200, Michael Snoyman wrote:

>> Ok, how about this:
>> transformers    H98 bits, registered hidden by default
>> mtl 2           re-exports transformers, adds type function stuff
>> mtl-fd          alternative that uses FDs, hidden by default

> Are you saying that mtl-2 would be the equivalent of transformers +
> monads-tf? That might not be a good call; monads-fd is probably more
> popular than monads-tf.

Yes mtl-2 would be transformers + monads-${the-right-one}

Though more precisely, it'd re-export transformers and contain

I'm not really saying whether it should be the tf or fd version. I've
not been taking part in that discussion.

But other people have been discussing it and whichever one it is that
they agree is the right default, that one should be labelled as mtl
version 2.

Also, I should say that it would be wrong to push the choice of FDs/TFs
onto everyone. We should just pick one. Some people know the difference
and can select an alternative. Everyone else just wants to use the same
one as everyone else is using.


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