An unique symbolic name.

class Name {

 /** The name of the symbol. */
 final String _name;

 /** The interned symbols. */
 static Map<String, Name> _interned = new HashMap();

 /** Factory for new symbol cells. */
 factory Name(String name) {
   return _interned.putIfAbsent(name, () => new Name._internal(name));
 }

 /** Internal constructor for symbol. */
 Name._internal(this._name);

 /** Returns the string representation of the symbolic name. */
 String toString() => _name;

}