import type { Optic, TryA, TryT, A, B, S, T } from './optic.js';
import type { Expected } from './errors.js';
import { Eq } from '../utils.js';
interface LensA<From, To> extends A {
    0: TryA<this, S<this> extends From ? To : Expected<From, S<this>>>;
}
interface LensT<From, To> extends T {
    0: TryT<this, S<this> extends From ? Eq<To, B<this>> extends true ? From : Expected<To, B<this>> : Expected<From, S<this>>>;
}
export type Lens<From, To> = Optic<'Lens', LensA<From, To>, LensT<From, To>>;
export declare const lens: <From, To>(view: (v: From) => To, update: (v: From, u: To) => From) => Lens<From, To>;
export {};