import { Either } from '../data/either';
import { Err, ErrorMessage } from './err';
/**
 * Except type represents a value that may fail with an error.
 *
 * It is a version of Either specialized with an Err type on the left-hand side.
 */
export type Except<A> = Either<Err, A>;
/**
 * raise an Except.
 *
 * This promotes a value to an Error wrapped inside a left.
 */
export declare const raise: <A>(msg: ErrorMessage | Err | Error) => Except<A>;
/**
 * attempt a synchronous computation that may throw an exception.
 */
export declare const attempt: <A>(f: () => A) => Except<A>;