Certainly `f` for functor. `k` is more for values than types (you usually know a continuation is some kind of (->)) but they'll often return `r`. > I love the

Certainly `f` for functor. `k` is more for values than types (you usually know a continuation is some kind of (->)) but they'll often return `r`. > I love the use of w for comonads: the rationale is apparently that it looks like an upside-down m. That's my understanding, yeah. > Is that an indexed lens ... parameterized over a monadic type? Presumably further parameterized by the focus, the source structure, the target structure, the focus again, the transformed focus, and some third structure. > I'd like a link to the video/article. Me too :-P I see a couple references in a google search but I'm not sure where I first heard it.