import { Kind, Type, Number as Number_, NaturalNumber, DigitList, String } from '..';
type _$digitToHexMap = {
    0: '0';
    1: '1';
    2: '2';
    3: '3';
    4: '4';
    5: '5';
    6: '6';
    7: '7';
    8: '8';
    9: '9';
    10: 'a';
    11: 'b';
    12: 'c';
    13: 'd';
    14: 'e';
    15: 'f';
};
/**
 * `_$toHex` is a type-level function that takes in a natural number `T`, and
 * returns the corresponding hex string, using lowercase letters.
 *
 * @template T - The natural number to convert.
 *
 * @example
 * ```ts
 * import { NaturalNumber } from "hkt-toolbelt";
 *
 * type Result = NaturalNumber._$toHex<999>; // '3e7'
 */
export type _$toHex<T extends Number_.Number, HEX_LIST = DigitList._$toHex<NaturalNumber._$toList<T>>> = String._$join<Type._$cast<{
    [K in keyof HEX_LIST]: _$digitToHexMap[Type._$cast<DigitList._$toNumber<Type._$cast<HEX_LIST[K], DigitList.DigitList>>, keyof _$digitToHexMap>];
}, string[]>>;
/**
 * `ToHex` is a type-level function that takes in a natural number `T`, and
 * returns the corresponding hex string, using lowercase letters.
 *
 * @template T - The natural number to convert.
 *
 * @example
 * ```ts
 * import { $, NaturalNumber } from "hkt-toolbelt";
 *
 * type Result = $<NaturalNumber.ToHex, 999>; // '3e7'
 * ```
 */
export interface ToHex extends Kind.Kind {
    f(x: Type._$cast<this[Kind._], Number_.Number>): _$toHex<typeof x>;
}
/**
 * Given a natural number, return the corresponding hex string, using lowercase
 * letters.
 *
 * @param {Number_.Number} x - The natural number to convert.
 *
 * @example
 * ```ts
 * import { NaturalNumber } from "hkt-toolbelt";
 *
 * const result = NaturalNumber.toHex(999)
 * //    ^? '3e7'
 * ```
 */
export declare const toHex: Kind._$reify<ToHex>;
export {};