srecord Complex(double re, double im) {
  double abs() { ret sqrt(re*re+im*im); }
  
  double re() { ret re; }
  double im() { ret im; }
  
  double phase aka angle() { ret Math.atan2(im, re); }
  double fracAngle() { ret fracNonNeg(angle()/twoPi()); } // angle as 0 to 1
  
  toString {
    if (im != 0)
      ret re == 0 ? im + "i" : re + plusPrefixUnlessMinus(str(im)) + "i";
    else
      ret str(re);
  }
}