code: function Fraction(a, b) {
  
      if (!(this instanceof Fraction)) {
        return new Fraction(a, b);
      }
  
      parse(a, b);
  
      if (Fraction['REDUCE']) {
        a = gcd(P["d"], P["n"]); // Abuse a
      } else {
        a = 1;
      }
  
      this["s"] = P["s"];
      this["n"] = P["n"] / a;
      this["d"] = P["d"] / a;
    }
docs: Module constructor
  
  @constructor
  @param {number|Fraction=} a
  @param {number=} b