code: Rule assignmentExpressionChaining() {
  		return Sequence(
  				inlineIfExpressionChaining(), set(),
  				Optional(Sequence(
  						assignmentOperator().label("operator"),
  						group.basics.optWS(),
  						assignmentExpressionChaining().label("RHS"))).label("assignment"),
  				set(actions.createAssignmentExpression(value(), text("assignment/Sequence/operator"), value("assignment"))));
  	}
docs: P14
  
  Not all of the listed operators are actually legal, but if not legal, then they are at least imaginable, so we parse them and flag them as errors in the AST phase.
  
  @see <a href="http://java.sun.com/docs/books/jls/third_edition/html/lexical.html#15.26">JLS section 15.26</a>