declare module 'gulp-ruby-sass' {

  /**
   * The interface includes all options that available for sass executable.
   * Options are converted from dashed to camelCase
   * @interface SassOptions
   */
  interface SassOptions {
    loadPath?: string | string[];
    require?: string;
    compass?: boolean;
    style?: string;
    force?: boolean;
    stopOnError?: boolean;
    scss?: boolean;
    defaultEncoding?: string;
    unixNewlines?: boolean;
    debugInfo?: boolean;
    lineNumbers?: boolean;
    lineComments?: boolean;
    check?: boolean;
    precision?: number;
    cacheLocation?: string;
    noCache?: boolean;
    trace?: boolean;
    quiet?: boolean;

    // Actually, there should be a string. However due to ts spec, overriding member should be the same type or a subtype.
    // http://stackoverflow.com/questions/19605557/incompatible-static-properties-in-three-d-ts-with-latest-typescript
    // We need Options.soucemap to be boolean, so here 'any' is used instead of string.
    sourcemap?: any;

    // All listed below options are acceptable by the sass executable and potentially may be used from js.
    // However I doubt are there cases when it's meaningful
    watch?: string;
    update?: string;
    stdin?: boolean;
    interactive?: boolean;
  }

  /**
   * The interface includes the node-ruby-sass only options.
   * Attention: sourcemap option type differs from the same SassOption's type.
   * @interface Options
   * @extends SassOptions
   */
  interface Options extends SassOptions {
    verbose?: boolean;
    bundleExec?: boolean;
    sourcemap?: boolean;
    container?: string;
  }

  /**
   * Object to be exported
   * @param {string} source - Filename or directory
   * @param {Options} options - Additional processing rules/options
   */
  //export default function sass(source: string, options?: Options): NodeJS.ReadableStream;

  interface Sass {
    (source: string, options?: Options): NodeJS.ReadWriteStream;
    logError(error?: string): void;
  }

  var _tmp: Sass;
  export = _tmp;
}