Re: [Haskell-cafe] Announcing OneTuple-0.1.0

On Thu, Oct 2, 2008 at 1:17 AM, Simon Brenner wrote:

On 10/2/08, ajb@spamcop.net wrote:

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G'day all.

Quoting John Dorsey :

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Contributions are welcome. The project could use a tutorial, and a decent test suite. Strict singleton tuples are planned for the next version.

I hope it has a Monad instance.

You could always use this one-tuple instead and get Functor, Monad and MonadFix for free: http://hackage.haskell.org/packages/archive/mtl/1.1.0.1/doc/html/Control-Mon...

But that one is different: newtype Identity a = Identity { runIdentity :: a } data OneTuple a = OneTuple { only :: a } So OneTuple has one more value than Identity (Identity Int has Identity _|_ and Identity n for each n, whereas OneTuple Int has _|_, OneTuple _|_, and OneTuple n for each n) Luke