import { type Maybe } from '../core/maybe.js';
/**
 *  Return one of this pattern:
 *
 *  1. a=others, b=null|undefined => _a_
 *  2. a=null|undefined, b=others => _b_
 *  3. Others => `undefined`
 */
export declare function xorForMaybe<T>(a: Maybe<T>, b: Maybe<T>): Maybe<T>;