CanPutP

Capability: a T can be constructed directly from an A, running f: A => B at the focus — the carrier-free surface of any optic whose carrier admits forgetful.ForgetfulApplicative (today: the Direct-carrier families, and Folds over an Applicative).

Prefer this trait in consuming signatures; the monomorphic CanPut alias covers A = B. See CanGet for the doctrine and the coherence rule.