Why folks use <> for same-type composition19 Jul 2020 ⇐ Notes archive
(This is an entry in my technical diary. There will likely be typos, mistakes, or wider logical leaps—the intent here is to “[let] others look over my shoulder while I figure things out.”)
And yesterday while re-watching Brandon Williams’ “Monoids, predicates and sorting functions” talk, I found a likely answer (timestamped link).
Functions in the form
(A) -> A — endomorphisms — come with a semigroup (and monoidal) structure and the diamond operator is a nod to that. The operator is subtly interchangeable with
Endo’s1 conformance leans on function composition under the hood.
The nominal veneer often used over the non-nominal
(A) -> Atype. ↩