import { Kind } from '../../kinds/index.js';
export declare namespace Option {
    interface None<A> {
        readonly _tag: 'None';
        readonly value?: A;
    }
    interface Some<A> {
        readonly _tag: 'Some';
        readonly value: A;
    }
}
export type Option<A> = Option.None<A> | Option.Some<A>;
export type OptionParamOf<O> = O extends Option<infer A> ? A : never;
export type OptionOf<O> = O extends Option.Some<infer A> ? Option<A> : O extends Option.None<infer A> ? Option<A> : O extends Option<infer A> ? Option<A> : never;
export interface TOption extends Kind.unary {
    return: Option<this['arg0']>;
}