import type * as P from "@principia/prelude";
import type { Option, URI, V } from "./model";
/**
 * ```haskell
 * extend_ :: Extend w => (w a, (w a -> b)) -> w b
 * ```
 */
export declare const extend_: <A, B>(wa: Option<A>, f: (wa: Option<A>) => B) => Option<B>;
/**
 * ```haskell
 * extend :: Extend w => (w a -> b) -> w a -> w b
 * ```
 */
export declare const extend: <A, B>(f: (wa: Option<A>) => B) => (wa: Option<A>) => Option<B>;
/**
 * ```haskell
 * duplicate :: Extend w => w a -> w (w a)
 * ```
 */
export declare const duplicate: <A>(wa: Option<A>) => Option<Option<A>>;
export declare const Extend: P.Extend<[URI], V>;
//# sourceMappingURL=extend.d.ts.map