[Haskell-cafe] Applicative of Applicative

[martin]

Hey guys, you made my day.

I had considered making it a monad, but I couldn't figure out what a->mb is supposed to mean in this context and so I
thought it was just an Applicative Functor. The idea that the presence of join makes it a monad was not obvious to me.

Now I can see the light. I can now imagine how I can have a Temporal Schedule which switches from "Winter Schedule" to
"Summer Schedule" at June 1st and a function which takes such a schedule and populates it with some Temporal Data.

Way cool. Does the rest of the world know that you haskellers can do such things?

> @M Farkas-Dyck
> I assume (pure = return) would make its argument time-invariant.

Exactly!