eval method

@override Object eval(DataInstance? model, EvaluationContext context)

Compares as booleans if either side is a boolean, else as numbers (within 1e-12) if either is a number, else as strings.

Implementation

@override
Object eval(DataInstance? model, EvaluationContext context) {
  final x = unpack(a.eval(model, context));
  final y = unpack(b.eval(model, context));
  final bool same;
  if (x is bool || y is bool) {
    same = (x is bool ? x : toBoolean(x)) == (y is bool ? y : toBoolean(y));
  } else if (x is double || y is double) {
    final dx = x is double ? x : toNumeric(x);
    final dy = y is double ? y : toNumeric(y);
    same = (dx - dy).abs() < 1e-12;
  } else {
    same = toXPathString(x) == toXPathString(y);
  }
  return equal == same;
}