compareTo method
Compares this object to another object.
Returns a value like a Comparator when comparing this to other.
That is, it returns a negative integer if this is ordered before other,
a positive integer if this is ordered after other,
and zero if this and other are ordered together.
The other argument must be a value that is comparable to this object.
Implementation
@override
int compareTo(Decimal other) {
var (d1, d2) = _unifyScale(this, other);
return d1._value.compareTo(d2._value);
}