Dear Haskellians,
A new C9 video in the series!
So, you folks already know most of this... except for maybe the
generalization of the Conway construction!
Best wishes,
--greg
-- Forwarded message --
From: Charles Torre <...>
Date: Tue, Jul 26, 2011 at 1:12 PM
Subject: C9 video
On 27 July 2011 10:31, Greg Meredith wrote:
> Dear Haskellians,
> A new C9 video in the series!
> So, you folks already know most of this... except for maybe the
> generalization of the Conway construction!
> Best wishes,
> --greg
Thanks for the heads up! I love these videos.
___
I'm always glad to see videos like this. I wish more people could have that
much fun playing with math ;).
It wouldn't really be suitable for your application but another interesting
generalization is to insert the 'Either' at the top level:
> data ConwayT m a
> = Pure a
> | ConwayT
>
For any who are interested, here's a quick and dirty Haskell version of the
generalized Conway game monad transformer described in the video. It uses two
newtypes, "L" and "R", to select from two possible implementations of the Monad
class.
(all the LANGUAGE pragmas are just to support a deriv
Dang, I should have played with both versions before sending this. The 'R'
instance has a very obvious error:
>return x = R (ConwayT (return (Left x)) mzero)
should be changed to
>return x = R (ConwayT mzero (return (Left x)))
Sorry!
-- James
On Jul 27, 2011, at 9:28 AM, James Cook
Dear James,
This is so cool! It's so natural to express this as a monad transformer.
It's great insight and it's just the sort of insight that Haskell and this
way of thinking about computation makes possible. Bravo!
Best wishes,
--greg
On Wed, Jul 27, 2011 at 6:33 AM, James Cook wrote:
> Dan
