System.Random instances for tuples

Antoine Latter aslatter at gmail.com
Tue Apr 17 04:55:32 CEST 2012


On Mon, Apr 16, 2012 at 9:04 PM, Dan Burton <danburton.email at gmail.com> wrote:
> Ever find yourself wanting to generate a tuple of random things? Instances
> are trivial to write in Haskell 98:

CC'ing the maintainer of the package as well.

It looks like it makes sense to me.

>
> instance (Random a, Random b) => Random (a, b) where
>   randomR ((loL, loR), (hiL, hiR)) g = ((l, r), g'')
>     where (l, g')  = randomR (loL, hiL) g
>           (r, g'') = randomR (loR, hiR) g'
>   random g = ((l, r), g'')
>     where (l, g')  = random g
>           (r, g'') = random g'
>
> Can we add instances like this to System.Random in the random package?
>
> -- Dan Burton
>
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