eo
eo is the sister project: an existential optics library for Scala 3, built on cats.
One Optic[S, T, A, B, F] trait, parameterised over a carrier F[_, _], unifies every
optic family; composition crosses families through Composer[F, G] bridges rather than
N² hand-written .andThen overloads. A function can demand a capability
(CanModify[T, String]) instead of a concrete type, and the caller supplies the optic
that proves it.
scala-cardinality shares eo's site pipeline: Laika with the Helium theme, the same
Cloudflare Pages deployment, and the same brand overlay.