Support for `cata`

[wookieb]

I would really like to see suport for catamorphism

Similar to: https://github.com/monet/monet.js/blob/master/docs/MAYBE.md#cata

[JSMonk]

Hey @wookieb. Sounds nice, I like it. The only thing, the name is not eloquent. What do you think, what will be a better name for the function?

[wookieb]

I really have no better idea for a name... Any suggestions?

[JSMonk]

mapBoth?

[wookieb]

https://www.npmjs.com/package/node-either-monad - uses fold https://github.com/sniptt-official/monads - uses match - which is also good https://folktalegithubio.readthedocs.io/en/latest/api/data/either/Either.html#cata - uses cata https://itnext.io/either-monad-a-functional-approach-to-error-handling-in-js-ffdc2917ab2 - uses matchWith https://gcanti.github.io/fp-ts/modules/Either.ts.html#mapping - uses fold

I believe let's go with fold since match accepts object and we can introduce it later.

[wookieb]

@JSMonk Do you agree to go with fold ?

[JSMonk]

I would like to name it match with one a few variants

[pawlufelice]

I prefer fold personally as it's descriptive of doing away with the monad.

[JSMonk]

I agree with you, but, and I'm open to discussion. But, my point of view is that the fold would confuse people from other non-pure-functional languages, because the fold method commonly is a collection method to make folding of the collection to some value.

• Rust: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.fold
• Kotlin: https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/fold.html
• Python: https://github.com/rethinkdb/docs/blob/master/api/python/aggregation/fold.md
• Clojure: https://clojuredocs.org/clojure.core.reducers/fold
• C++: https://en.cppreference.com/w/cpp/algorithm/ranges/fold_right

[wookieb]

Yes but this is fold in collections, not in a Maybe monad. Therefore I would go with it.

[wookieb]

I've encountered some issue with commiting and lint-staged failing with some error about yarn.lock. Had to switch to yarn 1.22.1 but that created some files not available in the repository before. I did not committed them.

@JSMonk can You please fix configuration of yarn package or provide details regard contribution?

[Voltra]

That's just bifoldMap from Bifoldable: https://hackage.haskell.org/package/base-4.18.0.0/docs/Prelude.html#v:bifoldMap