export interface Left<L> {
    _tag: 'Left';
    left: L;
}
export interface Right<R> {
    _tag: 'Right';
    right: R;
}
export declare type Either<L, R> = Left<L> | Right<R>;
export declare const isLeft: <L, R>(either: Either<L, R>) => either is Left<L>;
export declare const isRight: <L, R>(either: Either<L, R>) => either is Right<R>;
export declare const left: <L>(value: L) => Left<L>;
export declare const right: <R>(value: R) => Right<R>;