Struct LeapYearRule

Serializable rule expressing a calendar's leap-year behavior. Supports a simple "every N years" interval (e.g., Gregorian's every-4-years base rule) plus the choice of which month receives the extra day(s) and how many. The Gregorian "century not divisible by 400" exception is not modeled directly; for Gregorian-accurate leap years, callers can use System.DateTime via DateUtil instead of a custom calendar.

Inherited Members
Namespace: Scylla.Core.Time
Assembly: ScyllaCore.dll
Syntax
[Serializable]
public struct LeapYearRule

Properties

ExtraLeapDays

Number of extra days added in a leap year.

Declaration
public int ExtraLeapDays { get; }
Property Value
Type Description
int

HasLeapYears

Whether the calendar uses leap years at all.

Declaration
public bool HasLeapYears { get; }
Property Value
Type Description
bool

LeapMonthIndex

Zero-based month index that gains extra days in a leap year.

Declaration
public int LeapMonthIndex { get; }
Property Value
Type Description
int

LeapYearInterval

Every Nth year is a leap year.

Declaration
public int LeapYearInterval { get; }
Property Value
Type Description
int

Methods

EveryFourYears(int)

Convenience builder: every 4th year, the supplied month gains 1 extra day. Matches the Gregorian base rule (without the century exception).

Declaration
public static LeapYearRule EveryFourYears(int leapMonthIndex = 1)
Parameters
Type Name Description
int leapMonthIndex
Returns
Type Description
LeapYearRule

GetExtraDays(int, int)

Returns the number of extra days added to monthIndex for year. Zero unless the year is a leap year and the supplied month is the leap month.

Declaration
public int GetExtraDays(int year, int monthIndex)
Parameters
Type Name Description
int year
int monthIndex
Returns
Type Description
int

IsLeapYear(int)

Returns true if year is a leap year under this rule. Negative years apply the same modulo arithmetic so backward-running calendars continue to align leap years with their forward-running counterparts.

Declaration
public bool IsLeapYear(int year)
Parameters
Type Name Description
int year
Returns
Type Description
bool
Remarks

Year 0 is always a leap year by construction (any modulo with year 0 yields 0). For Gregorian-style calendars with a non-zero EpochYearOffset, this aligns naturally with designer expectation (year 0 in canonical coordinates corresponds to the displayed epoch year). For fictional calendars where year 0 has no special meaning, consider whether the leap alignment is intentional.

None()

Returns a disabled leap-year rule (the calendar has no leap years).

Declaration
public static LeapYearRule None()
Returns
Type Description
LeapYearRule