Re: [Haskell-cafe] Need ideas how to model the lack of something

On Mon, Dec 14, 2015 at 3:15 AM, martin wrote:

I started like this

data C a = C { insert :: a -> Maybe (C a), remove :: Maybe (a, C a) }

but I could not implement anything sensible on top of this.

And the reason you're stuck implementing anything sensible on top of this is because you've written an OOP-style specification of a data structure. You might want to review how Haskell declares data types. -- Kim-Ee