import Exceptional from "../util/Exceptional";
import Stream from "../util/Stream";
import Direction from "./Direction";
export default class Letter {
    private offset;
    static size: number;
    private static _values;
    /**
     * Values derived from General MIDI's program numbers
     * (https://en.wikipedia.org/wiki/General_MIDI)
     * and the octave convention for scientific pitch notation
     * (https://en.wikipedia.org/wiki/Scientific_pitch_notation)
     * Ex. The E (E4) above middle C (C4):
     *   - new octaves start on C
     *   - C4's program number is 48
     *   - increment that value by Letter.E's offset value (4)
     *   - E4: 48 + 4 == 52 == E4's program number
     */
    static A: Letter;
    static B: Letter;
    static C: Letter;
    static D: Letter;
    static E: Letter;
    static F: Letter;
    static G: Letter;
    private constructor();
    static values(): Letter[];
    ordinal(): number;
    static valueOf(letterString: string): Letter;
    getOffset(): number;
    static getLetters(direction?: Direction | Letter, startingLetter?: Letter): Letter[];
    static stream(direction?: Direction | Letter, startingLetter?: Letter): Stream<Letter>;
    static iterator(direction?: Direction | Letter, startingLetter?: Letter): Iterator<Letter>;
    static isValid(letterChar: string): boolean;
    static fromChar(letterChar: string): Exceptional<Letter>;
    toString(): string;
}