add method Null safety

bool add (
  1. E element
)
override

Adds value to the set.

Returns true if value (or an equal value) was not yet in the set. Otherwise returns false and the set is not changed.

Example:

var set = Set();
var time1 = DateTime.fromMillisecondsSinceEpoch(0);
var time2 = DateTime.fromMillisecondsSinceEpoch(0);
// time1 and time2 are equal, but not identical.
assert(time1 == time2);
assert(!identical(time1, time2));
set.add(time1);  // => true.
// A value equal to time2 exists already in the set, and the call to
// add doesn't change the set.
set.add(time2);  // => false.
assert(set.length == 1);
assert(identical(time1, set.first));

Implementation

bool add(E element) {
  int compare = _splay(element);
  if (compare == 0) return false;
  _addNewRoot(_SplayTreeSetNode(element), compare);
  return true;
}