Operator Scope of Action:
Operator First Added:
To make it easier to write rules succinctly, you can use the assignment:
$TheAttribute &= expression;
…which sets $TheAttribute to be true only if it is currently true AND the expression is also true. Thus, if $TheAttribute is false, the expression is still checked. An attribute that has no value set (or inherited) is evaluated as false.
$Urgent &= any(children,$Urgent)
Thus a project is considered urgent if it has been declared to be urgent itself and if any child is urgent.
See also the logical OR assignment.