/** A lexer that accepts additional, non-standard tokens. */
import { JSONPathEnvironment } from "./environment";
import { Token, TokenKind } from "./token";
/**
 * JSONPath lexical scanner.
 *
 * Lexer state is shared between this class and the current state function. A
 * new _Lexer_ instance is automatically created every time a path is tokenized.
 *
 * Use {@link tokenize} to get an array of {@link Token}'s for a JSONPath query.
 */
declare class Lexer {
    #private;
    readonly environment: JSONPathEnvironment;
    readonly path: string;
    /**
     * Filter nesting level.
     */
    filterLevel: number;
    /**
     * A running count of parentheses for each, possibly nested, function call.
     *
     * If the stack is empty, we are not in a function call. Remember that
     * function arguments can use arbitrarily nested in parentheses.
     */
    funcCallStack: number[];
    /**
     * A stack of parentheses and square brackets used to check for balanced
     * brackets.
     */
    bracketStack: Array<[string, number]>;
    /** Tokens resulting from tokenizing a JSONPath query. */
    tokens: Token[];
    /**
     * @param path - A JSONPath query.
     */
    constructor(environment: JSONPathEnvironment, path: string);
    get pos(): number;
    get start(): number;
    run(): void;
    emit(t: TokenKind): void;
    next(): string;
    ignore(): void;
    backup(): void;
    peek(): string;
    peekMatch(pattern: RegExp): boolean;
    accept(valid: Set<string>): boolean;
    acceptMatch(pattern: RegExp): boolean;
    acceptRun(valid: Set<string>): boolean;
    acceptMatchRun(pattern: RegExp): boolean;
    ignoreWhitespace(): boolean;
    error(msg: string): void;
}
/**
 * Return a lexer for _path_ and an array to be populated with Tokens.
 *
 * `lexer.run()` must be called to populate the returned tokens array.
 *
 * You probably want to use {@link tokenize} instead of _lex_. This function
 * is mostly for internal use, where we want to test the state of the returned
 * _lexer_ after tokens have been populated.
 *
 * @param path - A JSONPath query.
 * @returns A two-tuple containing a lexer for _path_ and an array to populate
 * with tokens.
 */
export declare function lex(environment: JSONPathEnvironment, path: string): [Lexer, Token[]];
/**
 * Scan _path_ and return an array of tokens to be parsed by the parser.
 * @param path - A JSONPath query.
 * @returns Tokens to be parsed by the parser.
 */
export declare function tokenize(environment: JSONPathEnvironment, path: string): Token[];
export {};