import { Kind, Type } from '..';
type _$lowercaseLetter = 'a' | 'b' | 'c' | 'd' | 'e' | 'f' | 'g' | 'h' | 'i' | 'j' | 'k' | 'l' | 'm' | 'n' | 'o' | 'p' | 'q' | 'r' | 's' | 't' | 'u' | 'v' | 'w' | 'x' | 'y' | 'z';
/**
 * `_$isLowercaseLetter` is a type-level function that takes in a string `S` and
 * returns a boolean indicating whether the string is a lowercase letter.
 *
 * @template {string} S - The string to check.
 *
 * @example
 * ```ts
 * import { String } from "hkt-toolbelt";
 *
 * type Result = String._$isLowercaseLetter<'a'>; // true
 * ```
 */
export type _$isLowercaseLetter<S extends string> = S extends _$lowercaseLetter ? true : false;
/**
 * `IsLowercaseLetter` is a type-level function that takes in a string `S` and
 * returns a boolean indicating whether the string is a lowercase letter.
 *
 * @template {string} S - The string to check.
 *
 * @example
 * ```ts
 * import { $, String } from "hkt-toolbelt";
 *
 * type Result = $<String.IsLowercaseLetter, 'a'>; // true
 * ```
 */
export interface IsLowercaseLetter extends Kind.Kind {
    f(x: Type._$cast<this[Kind._], string>): _$isLowercaseLetter<typeof x>;
}
/**
 * Given a string, return a boolean indicating whether the string is a
 * lowercase letter.
 *
 * @param {string} x - The string to check.
 *
 * @example
 * ```ts
 * import { String } from "hkt-toolbelt";
 *
 * const result = String.isLowercaseLetter('a')
 * //    ^? true
 * ```
 */
export declare const isLowercaseLetter: Kind._$reify<IsLowercaseLetter>;
export {};