toString method

@override String toString()

A string representation of this object.

Some classes have a default textual representation, often paired with a static parse function (like int.parse). These classes will provide the textual representation as their string representation.

Other classes have no meaningful textual representation that a program will care about. Such classes will typically override toString to provide useful information when inspecting the object, mainly for debugging or logging.

Implementation

@override
String toString() {
  final coeffs = getCoefficients();
  String mono(Rat n, int k, bool first) {
    if (k == 0) {
      return '$n';
    }
    if (n == Rat.one) {
      if (k == 1) {
        return 'x';
      } else {
        return 'x ^ $k';
      }
    } else {
      final n2 = first ? n : n.abs();
      if (k == 1) {
        return '$n2 * x';
      } else {
        return '$n2 * x ^ $k';
      }
    }
  }

  final nonzero = List.generate(coeffs.length, (i) => i)
      .where((i) => !coeffs[i].isZero)
      .toList();
  if (nonzero.length == 1) {
    return 'irrational(${mono(
      coeffs[nonzero[0]],
      nonzero[0],
      true,
    )})';
  }
  final result = StringBuffer('irrational(');
  for (var i = 0; i < nonzero.length; i++) {
    final ni = nonzero[i];
    final coeff = coeffs[ni];
    if (i != 0) {
      if (coeff.isNegative) {
        result.write(' - ');
      } else {
        result.write(' + ');
      }
    }
    result.write(mono(coeff, ni, i == 0));
  }
  result.write(')');
  return '$result';
}