import { NoSuchValueException } from '../internals/noSuchValueException';
import { Either } from './either';
/**
 * Used to represent an optional value
 */
export declare abstract class Option<A> {
    /**
     * Returns `true` if the instance is [[Some]]
     */
    readonly isSome: boolean;
    /**
     * Creates an [[Option]] from an [[Either]]
     */
    static fromEither<L, R>(either: Either<L, R>): Option<R>;
    /**
     * Checks if the Option type is of [[None]] type
     */
    static isNone<A>(A: Option<A>): A is None;
    /**
     * Checks if the Option type is of [[Some]] type
     */
    static isSome<A>(A: Option<A>): A is Some<A>;
    /**
     * Creates a [[None]] object
     */
    static none(): Option<never>;
    /**
     * Creates a [[Some]] object
     */
    static some<A>(A: A): Option<A>;
    /**
     * Converts an [[Option]] to an [[Either]]
     */
    abstract asEither: Either<NoSuchValueException, A>;
    /**
     * Returns `true` if the instance is [[None]]
     */
    abstract isNone: boolean;
    /**
     * Flattens the [[Option]] type
     */
    abstract chain<B>(ab: (A: A) => Option<B>): Option<B>;
    /**
     * Takes a seed `S` value and applies the FN if this is [[Some]]
     * Returns the seed `S` if this is [[None]]
     */
    abstract fold<S>(S: S, FN: (r: A, s: S) => S): S;
    /**
     * Gets the real value if this is of [[Some]] type.
     * If its not a [[Some]] type it returns the provided value.
     */
    abstract getOrElse(A: A): A;
    /**
     * Transforms the value inside the [[Option]] type.
     */
    map<B>(ab: (A: A) => B): Option<B>;
}
/**
 * Is an [[Option]] type that represents existence of a value.
 */
export declare class Some<A> extends Option<A> {
    readonly value: A;
    constructor(value: A);
    /**
     * Refer [[Option.chain]]
     */
    chain<B>(ab: (A: A) => Option<B>): Option<B>;
    /**
     * Refer [[Option.fold]]
     */
    fold<S>(S: S, some: (r: A, s: S) => S): S;
    /**
     * Refer [[Option.getOrElse]]
     */
    getOrElse(a: A): A;
    /**
     * Refer [[Option.isNone]]
     */
    readonly isNone: boolean;
    /**
     * Refer [[Option.asEither]]
     */
    readonly asEither: Either<NoSuchValueException, A>;
}
/**
 * Is an [[Option]] type that represents absence of any value.
 */
export declare class None extends Option<never> {
    /**
     * Refer [[Option.chain]]
     */
    chain<B>(ab: (A: never) => Option<B>): Option<B>;
    /**
     * Refer [[Option.fold]]
     */
    fold<S>(S: S, some: (r: never, s: S) => S): S;
    /**
     * Refer [[Option.getOrElse]]
     */
    getOrElse(A: never): never;
    /**
     * Refer [[Option.isNone]]
     */
    readonly isNone: boolean;
    /**
     * Refer [[Option.asEither]]
     */
    readonly asEither: Either<NoSuchValueException, never>;
}