On Sun, Jul 14, 2013 at 07:37:21AM -0700, Gabriel Gonzalez wrote:
On 07/14/2013 03:44 AM, Ben Millwood wrote:
On Sat, Jul 13, 2013 at 08:47:02PM -0700, Gabriel Gonzalez wrote:
I've been working on a "ListT done right" for submission into `transformers`. I could split it off into its own package, but I would like to first run it by you all, particularly Ross, to see if this can be included this in `transformers` because I feel that `transformers` is where this belongs.
I'm not sure. I'm inclined to think that the reason that ListT's violation of the monad laws upsets no-one is because no-one actually uses it. I don't think we should include the transformer just for the sake of having one.
This is a chicken-and-egg problem. Nobody uses it because it violates the laws and there is no good `ListT` implementation on Hackage.
It seems there are 140 packages on hackage using ListT (which surprised me, given its flaws), so I don't think we can quickly remove it from transformers or re-implement it under the same name.