declare type _Digit = 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9;
declare type UppercaseLetter = "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";
declare type LowercaseLetter = Lowercase<UppercaseLetter>;
/** Alphabet letter. */
export declare type Alpha = UppercaseLetter | LowercaseLetter;
/** Digit letter. */
export declare type Digit = `${_Digit}`;
/** [tchar](https://www.rfc-editor.org/rfc/rfc9110.html#section-5.6.2-2) letter. */
export declare type Tchar = "!" | "#" | "$" | "%" | "&" | "'" | "*" | "+" | "-" | "." | "^" | "_" | "`" | "|" | "~" | Digit | Alpha;
/** Representation of [token](https://www.rfc-editor.org/rfc/rfc9110.html#section-5.6.2-2). */
export declare type Token = `${Tchar}${string}`;
/** Whether the input is [token](https://www.rfc-editor.org/rfc/rfc9110.html#section-5.6.2-2) or not.
 *
 * @example
 * ```ts
 * import { isToken } from "https://deno.land/x/http_utils@$VERSION/token.ts";
 * import {
 *   assert,
 *   assertFalse,
 * } from "https://deno.land/std@$VERSION/testing/asserts.ts";
 *
 * assert(isToken("token"));
 * assert(isToken("*!~"));
 * assertFalse(isToken(""));
 * ```
 */
export declare function isToken(input: string): input is Token;
/** Whether the input is [tchar](https://www.rfc-editor.org/rfc/rfc9110.html#section-5.6.2-2) or not.
 *
 * @example
 * ```ts
 * import { isTchar } from "https://deno.land/x/http_utils@$VERSION/token.ts";
 * import {
 *   assert,
 *   assertFalse,
 * } from "https://deno.land/std@$VERSION/testing/asserts.ts";
 *
 * assert(isTchar("!"));
 * assert(isTchar("a"));
 * assert(isTchar("Z"));
 * assertFalse(isTchar(""));
 * ```
 */
export declare function isTchar(input: string): input is Tchar;
export {};