Re: [Haskell-cafe] [ANN] anonymous-sums

* adam vogt [2014-02-13 19:51:34-0500]

On Thu, Feb 13, 2014 at 4:36 PM, Omari Norman wrote:

...

If there is already something like this out there (or some elegant way to do this that doesn't involve hairy extensions), please let me know and I will be all too happy to deprecate this.

Omari

Hi Omari,

You could use:

type S3 a b c = (Maybe a, Maybe b, Maybe c)

And then prove to yourself that only one entry is Just. This lets you use of classes that work with tuples such as Field1 through Field9 from lens or things from http://hackage.haskell.org/package/tuple.

At least that's the strategy in < http://hackage.haskell.org/package/HList-0.3.2.0/docs/Data-HList-Variant.htm...

...

.

Yes, this solution is highly recommended... by @EvilHaskellTips :-) https://twitter.com/EvilHaskellTips/status/433403451054096384 Roman