On Wed, Aug 22, 2012 at 7:16 PM, yi huang
I have a `newtype Yun a = Yun { unYun :: ReaderT YunEnv (ResourceT IO) a }` , and i need to define an instance of `MonadBaseControl IO` for it. Newtype instance deriving don't work here. I guess the answer is simple, i just can't figure it out, hope anybody can lightening me.
I had the same problem some time ago. In my case it's StateT instead of ReaderT, but it's the same idea. The tough part is getting around the crazy CPS -- it's supposed to help with performance, but at the cost of usability. Anyway, here's my implementation: https://github.com/lfairy/haskol/blob/master/Web/KoL/Core.hs#L58 Michael Snoyman has written a tutorial as well: http://www.yesodweb.com/book/monad-control I'd recommend printing it out and going over it slowly -- it can get pretty dense at times. Chris
Best regards. Yihuang.
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