Church These

A church encoding of the These data structure inspired by @joneshf's Elm These, this article featuring Church encoding, and @dominictarr's pull streams.

Vibe

I've not curried the functions which has reduced opportunities for pointfree. There's no check that you always pass in all three reducing functions. It might make sense to add one, but I'm erring on the side of bare bones

TODO

• Add further static-land support (how to deal with constraints?)
• JSVerify