A method, apparatus, and system in which a resultant date is modified based upon the date-effecting condition. A date input is received as an expression having one or more components and other parameters that modify the value of a particular component. The expression establishes and manipulates a target date in order to determine a resultant date. A determination is made if a date-effecting condition is associated with the expression. The resultant date is modified based upon the date-effecting condition.