sclass DateStructures {
  asclass SomeDate {}
  asclass SomeWeek > SomeDate {}
  asclass DateProp {} // proposition on a date, e.g. a date range

  // years
  srecord Year(int year) > SomeDate {}
  srecord CurrentYearPlus(int nYears) > SomeDate {}
  
  // months
  srecord Month(int month, Year year) > SomeDate {
    Month(int month) { this(month, null); }
  }
  srecord CurrentMonthPlus(int nMonths) > SomeDate {}
  
  // weeks
  srecord Week(int week, Year year) > SomeWeek {}
  srecord CurrentWeekPlus(int nWeeks) > SomeWeek {}

  // days
  srecord Day(int day, Month month) > SomeDate {}
  srecord TodayPlus(int nDays) > SomeDate {}

  // weekdays
  srecord Weekday(int weekday, SomeWeek week) > SomeDate {
    // weekday is in Java count (1=Sunday)
    Weekday(int weekday) { this.weekday = weekday; }
  }

  // hours
  srecord Hour(int hour, Bool isPM, Day day) > SomeDate {
    Hour(int hour, Bool isPM) { this(hour, isPM, null); }
  }
  srecord CurrentHourPlus(int nHours) > SomeDate {}

  // minutes
  srecord Minute(int minute, Hour hour) > SomeDate {}
  srecord CurrentMinutePlus(int nMinutes) > SomeDate {}
  
  // seconds
  srecord Second(int second, Minute minute) > SomeDate {}
  
  // special stuff
  srecord BeginningOfTime > SomeDate {}
  srecord EndOfTime > SomeDate {}
  
  // date ranges & boolean operations
  srecord DateRange(SomeDate from, SomeDate to) > DateProp {}
  srecord Or(DateProp a, DateProp b) > DateProp {}
  srecord And(DateProp a, DateProp b) > DateProp {}
  srecord Not(DateProp a) > DateProp {}
}