import { Type, Number, DigitList, Kind } from '..';
/**
 * A type-level utility that recursively breaks down a number into a list of its digits.
 * This utility is primarily used within the `NaturalNumber.ToList` interface.
 *
 * @template S The number to be converted into a list of digits.
 * @template O An accumulator used during the recursive breakdown process. Defaults to an empty list.
 *
 * @returns A list of digits representing the number. If the number is zero, it returns a list with a single '0'.
 *
 * @example
 * // Convert the number 42 into a list of digits:
 * type ListOfDigits = _$toList<42>; // This will be inferred as ['4', '2']
 */
export type _$toList<S extends Number.Number, O extends string[] = []> = Number._$toString<S> extends `${infer Head}${infer Tail}` ? _$toList<Tail, [...O, Head]> : O extends DigitList.DigitList ? O : ['0'];
/**
 * Represents a type-level utility to convert a natural number into a list of its digits.
 * The digits are represented as strings.
 *
 * @template F - The number to be converted.
 *
 * @returns A list of digits representing the number. If the number is not a natural number, it returns `never`.
 *
 * @example
 * // Convert the number 42 into a list of digits:
 * type ListOfDigits = $<NaturalNumber.ToList, 42>; // This will be inferred as ['4', '2']
 * // Convert the number 0 into a list of digits:
 * type ZeroList = $<NaturalNumber.ToList, 0>; // This will be inferred as ['0']
 */
export interface ToList extends Kind.Kind {
    f(x: Type._$cast<this[Kind._], Number.Number>): Number._$isNatural<typeof x> extends true ? _$toList<typeof x> : never;
}
/**
 * Given a number, convert it to a list of digits.
 *
 * @param {number} x - The number to convert to a list of digits.
 *
 * @example
 * ```ts
 * import { NaturalNumber } from "hkt-toolbelt";
 *
 * const result = NaturalNumber.toList(42)
 * //    ^? ['4', '2']
 * ```
 */
export declare const toList: Kind._$reify<ToList>;