fold is bimap

I got a question about fold, so I took a look at the signature:

@Task(α, β) => (α → γ), (β → γ) → Task(δ, γ)

This is not a fold, this is bimap.

[robotlolita]

Folktale 2’s task only has willMatchWith. No way of writing fold without deep coroutines/fibers or threads 😦

@raqystyle an arbitrary type variable. There it just means it’s not the same type as a, but it doesn’t have any equivalent runtime set of values (it’s not really unit or null). In that sense, it’s closer to TypeScript’s never.

[raqystyle]

@robotlolita thank you for the explanation!