/**
 * InputState abstraction, exposed to matchers.
 * Backed by a buffer or stream that is managed transparently.
 */
export interface InputState {
    readonly offset: number;
    /**
     * InputStateListeners, if set.
     * InputStateListener instances will have seen only the characters up to this point.
     */
    readonly listeners?: Listeners;
    /**
     * Is the input exhausted?
     * @return {boolean}
     */
    exhausted(): boolean;
    /**
     * Consume the given string if our input begins with it. Otherwise fail
     * @param s string that we must find
     * @param message description of what we're doing to help in diagnosing problems
     * @return {InputState}
     */
    consume(s: string, message: string): InputState;
    /**
     * Advance one character in the input
     * @return {InputState}
     */
    advance(): InputState;
    /**
     * Skip to before this pattern. Exhaust input if necessary.
     * Return tuple of what was skipped and the resulting InputState
     * @param what what to skip to
     */
    skipTo(what: string): Skipped;
    /**
     * Skip input while it matches the given function
     * @param skip function to test characters
     * @param n number of characters to test for skip function
     * Return tuple of what was skipped and the resulting InputState
     * @return {InputState}
     */
    skipWhile(skip: (s: string) => boolean, n: number): Skipped;
    /**
     * Look ahead in the input without consuming characters
     * @param n number of characters to look ahead
     * @return {string}
     */
    peek(n: number): string;
}
export interface Listeners {
    [key: string]: InputStateListener;
}
/**
 * Listener invoked when characters are consumed from an InputState.
 * Useful for implementing a state machine or tracking previously seen characters.
 */
export interface InputStateListener {
    /**
     * Invoked when the given characters were read from the input
     * @param s input read
     */
    read(s: string): this;
    /**
     * Return an independent clone of this listener
     */
    clone(): InputStateListener;
}
export interface Skipped {
    skipped: string;
    state: InputState;
}