export namespace PatternUtil {
  export const fix = (str: string): string => {
    const first: number = str.indexOf(STRING);
    const last: number = str.lastIndexOf(STRING);
    return [
      first === -1 || none("(")(str.slice(0, first)) ? "^" : "",
      str,
      last === -1 || none(")")(str.slice(last + STRING.length)) ? "$" : "",
    ].join("");
  };

  export const escape = (str: string): string => {
    return str.replace(/[|\\/{}()[\]^$+*?.]/g, "\\$&").replace(/-/g, "\\x2d");
  };

  export const NUMBER =
    "[+-]?" + // optional sign
    "\\d+(?:\\.\\d+)?" + // integer or decimal
    "(?:[eE][+-]?\\d+)?"; // optional exponent
  export const BOOLEAN = "true|false";
  export const STRING = "(.*)";
}

const none =
  (parenthesis: string) =>
  (str: string): boolean => {
    for (const ch of str) if (ch !== parenthesis) return true;
    return false;
  };