ModifyF

Optional → ModifyF. Mirror of either2modify split across Affine.Hit / Affine.Miss; miss uses widenB instead of allocating a fresh Miss.

Optional → ModifyF. Mirror of either2modify split across Affine.Hit / Affine.Miss; miss uses widenB instead of allocating a fresh Miss.

Same-carrier composition for Optic[…, ModifyF] — modify.andThen(modify).

Encoding: Z = (Fst[Xo], Snd[Xi]). composeTo seeds the ModifyF with (outer-source, identity[C]) — no inner.to call needed because ModifyF's continuation is structurally identity[C] at every canonical construction site (every bundled ModifyF optic uses coerceToModify or optics.Modify.apply, both of which seed identity). composeFrom extracts the user's c2d: C => D from the post-map continuation and applies it through inner.from then outer.from, matching the deferred-modify semantic composedModify(c2d)(s) = outer.modify(inner.modify(c2d))(s).

The asInstanceOf casts coerce abstract Fst[Xo] / Snd[Xo] / Fst[Xi] / Snd[Xi] to the canonical (S, A) / (A, C) decomposition. Sound under the universal ModifyF convention, unsafe only for hand-built ModifyF optics that violate it — and there's no public API path to build such an optic.

Prism → ModifyF. Hit writes f(a) through the Prism's build path; miss passes the leftover back via o.from(Left(xo)) — observably the same as the Prism's own .modify(f).

Prism → ModifyF. Hit writes f(a) through the Prism's build path; miss passes the leftover back via o.from(Left(xo)) — observably the same as the Prism's own .modify(f).

ForgetfulFunctor[ModifyF] — maps the continuation through f, leaving the source unchanged. Unlocks .modify / .replace on Modify-carrier optics.

ForgetfulFunctor[ModifyF] — maps the continuation through f, leaving the source unchanged. Unlocks .modify / .replace on Modify-carrier optics.

ForgetfulTraverse[ModifyF, Distributive] — lifts an effectful B => G[C] through the continuation under Distributive[G] (the right shape for read-once / write-once Modify).

ForgetfulTraverse[ModifyF, Distributive] — lifts an effectful B => G[C] through the continuation under Distributive[G] (the right shape for read-once / write-once Modify).

Lens → ModifyF. Every Lens is-a Modify; powers cross-carrier lens.andThen(modify) via Morph[Tuple2, ModifyF].

Lens → ModifyF. Every Lens is-a Modify; powers cross-carrier lens.andThen(modify) via Morph[Tuple2, ModifyF].