/**
 * Represents a token.
 */
export interface Token {
    /**
     * The value of the token.
     */
    readonly value: string;
    /**
     * The raw value of the token e.g. with quotes.
     */
    readonly raw: string;
    /**
     * Trailing whitespace.
     */
    readonly trailing: string;
}
/**
 * Joins tokens together.
 * By default, this keeps as much of the original input as possible.
 *
 * ```ts
 * // Note three trailing spaces.
 * const tokens = new Lexer('hello   "world"')
 *   .setQuotes([['"', '"']])
 *   .lex();
 *
 * console.log(joinTokens(tokens));
 * >>> 'hello   "world"'
 *
 * console.log(joinTokens(tokens, ' ', false));
 * >>> 'hello world'
 * ```
 *
 * @param tokens - Tokens to join.
 * @param separator - The separator, if null, will use original trailing whitespace; defaults to null.
 * @param raw - Whether to use raw values e.g. with quotes; defaults to true.
 * @returns The joined string.
 */
export declare function joinTokens(tokens: Token[], separator?: string | null, raw?: boolean): string;
/**
 * A function to match a prefix.
 * @param s - A string that may start with the prefix.
 * @returns The length of the prefix if there is one.
 */
export declare type MatchPrefix = (s: string) => number | null;
/**
 * Extracts a command from the first one or two tokens from a list of tokens.
 * The command format is '<prefix> <command>', and the space is optional.
 * @param matchPrefix - A function that gives the length of the prefix if there is one.
 * @param tokens - Tokens to check.
 * @param mutate - Whether to mutate the list of tokens.
 * @returns The token containing the name of the command.
 * This may be a token from the list or a new token.
 */
export declare function extractCommand(matchPrefix: MatchPrefix, tokens: Token[], mutate?: boolean): Token | null;