[Haskell-cafe] Announcing OneTuple-0.1.0

[Luke Palmer]

Hmm, it looks like you forgot to write a Traversable instance.  I don't believe:

  sequenceA (OneTuple [1,2,3,4]) = _|_

is correct.  Here is my contribution!

  instance Traversable OneTuple where
      sequenceA (OneTuple x) = fmap OneTuple x

Luke

On Thu, Oct 2, 2008 at 12:56 AM, John Dorsey <haskell at colquitt.org> wrote:
> Fellow Haskellers,
>
> Much attention has been paid over the years to the regrettable
> omission of singleton tuples from Haskell.
>
> I am pleased to announce OneTuple, a humble implementation of the
> singleton tuple for Haskell.  Now you can:
>
> *  Wrap a single value of any type in a OneTuple !
>
> *  Pattern match to retrieve your value !
>
> *  Solve any of the software problems that cannot be solved without
>   the singleton tuple !
>
> *  Enjoy instances for all the classes normal tuples have, plus more !
>
> *  Proclaim feature parity with Python !
>
> Note:  the singleton tuple does not support tuple syntax.
>
> Contributions are welcome.  The project could use a tutorial, and a
> decent test suite.  Strict singleton tuples are planned for the next
> version.
>
> Enjoy!
>
> Regards,
> John Dorsey
>
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