eveff VS recursion-schemes

I would also like to add: https://github.com/xnning/EvEff/

Consider recursion schemes! It let's you separate the logic of how your recursion is structured on your data, and the logic of what you're doing on each recursion stage. So e.g. you can write the core logic of a recursive linked list summation as just fun x accum -> x + accum, and then you just find the appropriate recursion scheme to pipe the list values into x and handle recursing to build accum (a catamorphism in this case)

But wait, there's more! One of the two challenges was the recursion-schemes library. I wrote some examples, but the output I was getting from that example was not what I expected. I dug further, and it turned out to be a bug in the library! In addition to the documentation, I thus also worked on a fix for that bug.

It's a pretty complicated bug, documented in details at https://github.com/recursion-schemes/recursion-schemes/issues/50

It’s also trivial and easy in Haskell — you just need an instance of `Foldable` or `Traversable` on your collection, and then you can fold or traverse it in a configurable way. Or for recursive structures, use https://hackage.haskell.org/package/recursion-schemes. Or even just pass a traversal function as an argument for maximum flexibility.

https://hackage.haskell.org/package/recursion-schemes is the "normal" library for this type of generalized folding. It even contains Base instances for Maybe and Either.

I've been working on a system which uses recursion-schemes to annotate a recursive type. The annotated tree itself is pretty simple; at each level, we pair the annotation with the base functor, or

Yes please! Right now all of my open-source projects (most notably hint and recursion-schemes) are about to drop into barely-updated mode, and while I knew this would happen and have been working towards finding co-maintainers, I am now realizing that it wasn't enough. I think such a website would definitely have helped, and I am hoping that once it launches, I'll be able to use it to find some co-maintainers to tide over my projects until I become available again.

A short (?) primer before you dive into recursion-schemes:

And here is the branch containing my implementation.

Recursion schemes: I, admittedly, don't know a whole lot about recursion schemes, but IIUC, they let you write datatype-generic iterative algorithms and all you have to do is define a few primitives per each datatype you'd like to use those algorithms on. See recursion-schemes: Representing common recursion patterns as higher-order functions.