/**
 * ChainRec
 *
 * 1. M.chainRec((next, done, v) => p(v) ? d(v).map(done) : n(v).map(next), i) is equivalent to
 *    (function step(v) { return p(v) ? d(v) : n(v).chain(step); }(i)) (equivalence)
 * 2. Stack usage of M.chainRec(f, i) must be at most a constant multiple of the stack usage of f itself
 *
 * chainRec :: ChainRec m => ((a -> c, b -> c, a) -> m c, a) -> m b
 */
import { Either } from '../Either';
import { Chain, Chain1, Chain2 } from './Chain';
import { HKT, KindOf, URIS } from './HKT';
export interface ChainRec<F> extends Chain<F> {
    readonly chainRec: <A, B>(fa: A, f: (a: A) => HKT<F, Either<A, B>>) => HKT<F, B>;
}
export interface ChainRec1<F extends URIS> extends Chain1<F> {
    readonly chainRec: <A, B>(fa: A, f: (a: A) => KindOf<F, [Either<A, B>]>) => KindOf<F, [B]>;
}
export interface ChainRec2<F extends URIS> extends Chain2<F> {
    readonly chainRec: <E, A, B>(fa: A, f: (a: A) => KindOf<F, [E, Either<A, B>]>) => KindOf<F, [E, B]>;
}
/**
 * `ChainRec` helper. Returns until the next is `Right`.
 */
export declare const tailRec: <A, B>(init: A, f: (a: A) => Either<A, B>) => B;