Safe Haskell	Trustworthy
Language	Haskell2010

Data.Time.Calendar.Compat

Contents

Days
DayPeriod
CalendarDiffTime
Year, month and day
Gregorian calendar
Week
Type aliases

Synopsis

newtype Day = ModifiedJulianDay {
- toModifiedJulianDay :: Integer
}
addDays :: Integer -> Day -> Day
diffDays :: Day -> Day -> Integer
class Ord p => DayPeriod p where
- periodFirstDay :: p -> Day
- periodLastDay :: p -> Day
- dayPeriod :: Day -> p
periodAllDays :: DayPeriod p => p -> [Day]
periodLength :: DayPeriod p => p -> Int
periodFromDay :: DayPeriod p => Day -> (p, Int)
periodToDay :: DayPeriod p => p -> Int -> Day
periodToDayValid :: DayPeriod p => p -> Int -> Maybe Day
data CalendarDiffDays = CalendarDiffDays {
- cdMonths :: Integer
- cdDays :: Integer
}
calendarDay :: CalendarDiffDays
calendarWeek :: CalendarDiffDays
calendarMonth :: CalendarDiffDays
calendarYear :: CalendarDiffDays
scaleCalendarDiffDays :: Integer -> CalendarDiffDays -> CalendarDiffDays
type Year = Integer
pattern CommonEra :: Integer -> Year
pattern BeforeCommonEra :: Integer -> Year
type MonthOfYear = Int
pattern January :: MonthOfYear
pattern February :: MonthOfYear
pattern March :: MonthOfYear
pattern April :: MonthOfYear
pattern May :: MonthOfYear
pattern June :: MonthOfYear
pattern July :: MonthOfYear
pattern August :: MonthOfYear
pattern September :: MonthOfYear
pattern October :: MonthOfYear
pattern November :: MonthOfYear
pattern December :: MonthOfYear
type DayOfMonth = Int
toGregorian :: Day -> (Year, MonthOfYear, DayOfMonth)
fromGregorian :: Year -> MonthOfYear -> DayOfMonth -> Day
fromGregorianValid :: Year -> MonthOfYear -> DayOfMonth -> Maybe Day
showGregorian :: Day -> String
gregorianMonthLength :: Year -> MonthOfYear -> DayOfMonth
addGregorianMonthsClip :: Integer -> Day -> Day
addGregorianMonthsRollOver :: Integer -> Day -> Day
addGregorianYearsClip :: Integer -> Day -> Day
addGregorianYearsRollOver :: Integer -> Day -> Day
addGregorianDurationClip :: CalendarDiffDays -> Day -> Day
addGregorianDurationRollOver :: CalendarDiffDays -> Day -> Day
diffGregorianDurationClip :: Day -> Day -> CalendarDiffDays
diffGregorianDurationRollOver :: Day -> Day -> CalendarDiffDays
isLeapYear :: Year -> Bool
data DayOfWeek
- = Monday
- | Tuesday
- | Wednesday
- | Thursday
- | Friday
- | Saturday
- | Sunday
dayOfWeek :: Day -> DayOfWeek
dayOfWeekDiff :: DayOfWeek -> DayOfWeek -> Int
firstDayOfWeekOnAfter :: DayOfWeek -> Day -> Day
weekAllDays :: DayOfWeek -> Day -> [Day]
weekFirstDay :: DayOfWeek -> Day -> Day
weekLastDay :: DayOfWeek -> Day -> Day
pattern YearMonthDay :: Year -> MonthOfYear -> DayOfMonth -> Day

Days

newtype Day #

The Modified Julian Day is a standard count of days, with zero being the day 1858-11-17.

Constructors

ModifiedJulianDay
Fields toModifiedJulianDay :: Integer

Instances

Instances details

Data Day
Instance details Defined in Data.Time.Calendar.Days Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Day -> c Day # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Day # toConstr :: Day -> Constr # dataTypeOf :: Day -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Day) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Day) # gmapT :: (forall b. Data b => b -> b) -> Day -> Day # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Day -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Day -> r # gmapQ :: (forall d. Data d => d -> u) -> Day -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Day -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Day -> m Day # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Day -> m Day # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Day -> m Day #
Enum Day
Instance details Defined in Data.Time.Calendar.Days Methods succ :: Day -> Day # pred :: Day -> Day # toEnum :: Int -> Day # fromEnum :: Day -> Int # enumFrom :: Day -> [Day] # enumFromThen :: Day -> Day -> [Day] # enumFromTo :: Day -> Day -> [Day] # enumFromThenTo :: Day -> Day -> Day -> [Day] #
Generic Day Source #
Instance details Defined in Data.Time.Orphans Associated Types type Rep Day :: Type -> Type # Methods from :: Day -> Rep Day x # to :: Rep Day x -> Day #
Ix Day
Instance details Defined in Data.Time.Calendar.Days Methods range :: (Day, Day) -> [Day] # index :: (Day, Day) -> Day -> Int # unsafeIndex :: (Day, Day) -> Day -> Int # inRange :: (Day, Day) -> Day -> Bool # rangeSize :: (Day, Day) -> Int # unsafeRangeSize :: (Day, Day) -> Int #
NFData Day
Instance details Defined in Data.Time.Calendar.Days Methods rnf :: Day -> () #
Eq Day
Instance details Defined in Data.Time.Calendar.Days Methods (==) :: Day -> Day -> Bool # (/=) :: Day -> Day -> Bool #
Ord Day
Instance details Defined in Data.Time.Calendar.Days Methods compare :: Day -> Day -> Ordering # (<) :: Day -> Day -> Bool # (<=) :: Day -> Day -> Bool # (>) :: Day -> Day -> Bool # (>=) :: Day -> Day -> Bool # max :: Day -> Day -> Day # min :: Day -> Day -> Day #
Hashable Day Source #
Instance details Defined in Data.Time.Orphans Methods hashWithSalt :: Int -> Day -> Int # hash :: Day -> Int #
DayPeriod Day
Instance details Defined in Data.Time.Calendar.Days Methods periodFirstDay :: Day -> Day # periodLastDay :: Day -> Day # dayPeriod :: Day -> Day #
ISO8601 Day	`yyyy-mm-dd` (ISO 8601:2004(E) sec. 4.1.2.2 extended format)
Instance details Defined in Data.Time.Format.ISO8601 Methods iso8601Format :: Format Day #
Lift Day Source #
Instance details Defined in Data.Time.Orphans Methods lift :: Quote m => Day -> m Exp # liftTyped :: forall (m :: Type -> Type). Quote m => Day -> Code m Day #
type Rep Day Source #
Instance details Defined in Data.Time.Orphans type Rep Day = D1 ('MetaData "Day" "Data.Time.Calendar.Days" "time-1.12.2" 'True) (C1 ('MetaCons "ModifiedJulianDay" 'PrefixI 'True) (S1 ('MetaSel ('Just "toModifiedJulianDay") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Integer)))

addDays :: Integer -> Day -> Day #

diffDays :: Day -> Day -> Integer #

DayPeriod

class Ord p => DayPeriod p where #

The class of types which can be represented as a period of days.

Since: time-1.12.1

Methods

periodFirstDay :: p -> Day #

Returns the first Day in a period of days.

periodLastDay :: p -> Day #

Returns the last Day in a period of days.

dayPeriod :: Day -> p #

Get the period this day is in.

Instances

Instances details

DayPeriod Day
Instance details Defined in Data.Time.Calendar.Days Methods periodFirstDay :: Day -> Day # periodLastDay :: Day -> Day # dayPeriod :: Day -> Day #
DayPeriod Month
Instance details Defined in Data.Time.Calendar.Month Methods periodFirstDay :: Month -> Day # periodLastDay :: Month -> Day # dayPeriod :: Day -> Month #
DayPeriod Quarter
Instance details Defined in Data.Time.Calendar.Quarter Methods periodFirstDay :: Quarter -> Day # periodLastDay :: Quarter -> Day # dayPeriod :: Day -> Quarter #

periodAllDays :: DayPeriod p => p -> [Day] #

A list of all the days in this period.

Since: time-1.12.1

periodLength :: DayPeriod p => p -> Int #

The number of days in this period.

Since: time-1.12.1

periodFromDay :: DayPeriod p => Day -> (p, Int) #

Get the period this day is in, with the 1-based day number within the period.

periodFromDay (periodFirstDay p) = (p,1)

Since: time-1.12.1

periodToDay :: DayPeriod p => p -> Int -> Day #

Inverse of periodFromDay.

Since: time-1.12.1

periodToDayValid :: DayPeriod p => p -> Int -> Maybe Day #

Validating inverse of periodFromDay.

Since: time-1.12.1

CalendarDiffTime

data CalendarDiffDays #

Constructors

CalendarDiffDays
Fields cdMonths :: Integer cdDays :: Integer

Instances

Instances details

Data CalendarDiffDays	Since: time-1.9.2
Instance details Defined in Data.Time.Calendar.CalendarDiffDays Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> CalendarDiffDays -> c CalendarDiffDays # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c CalendarDiffDays # toConstr :: CalendarDiffDays -> Constr # dataTypeOf :: CalendarDiffDays -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c CalendarDiffDays) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c CalendarDiffDays) # gmapT :: (forall b. Data b => b -> b) -> CalendarDiffDays -> CalendarDiffDays # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> CalendarDiffDays -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> CalendarDiffDays -> r # gmapQ :: (forall d. Data d => d -> u) -> CalendarDiffDays -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> CalendarDiffDays -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> CalendarDiffDays -> m CalendarDiffDays # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> CalendarDiffDays -> m CalendarDiffDays # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> CalendarDiffDays -> m CalendarDiffDays #
Monoid CalendarDiffDays	Additive
Instance details Defined in Data.Time.Calendar.CalendarDiffDays Methods mempty :: CalendarDiffDays # mappend :: CalendarDiffDays -> CalendarDiffDays -> CalendarDiffDays # mconcat :: [CalendarDiffDays] -> CalendarDiffDays #
Semigroup CalendarDiffDays	Additive
Instance details Defined in Data.Time.Calendar.CalendarDiffDays Methods (<>) :: CalendarDiffDays -> CalendarDiffDays -> CalendarDiffDays # sconcat :: NonEmpty CalendarDiffDays -> CalendarDiffDays # stimes :: Integral b => b -> CalendarDiffDays -> CalendarDiffDays #
Generic CalendarDiffDays Source #
Instance details Defined in Data.Time.Orphans Associated Types type Rep CalendarDiffDays :: Type -> Type # Methods from :: CalendarDiffDays -> Rep CalendarDiffDays x # to :: Rep CalendarDiffDays x -> CalendarDiffDays #
Show CalendarDiffDays
Instance details Defined in Data.Time.Calendar.CalendarDiffDays Methods showsPrec :: Int -> CalendarDiffDays -> ShowS # show :: CalendarDiffDays -> String # showList :: [CalendarDiffDays] -> ShowS #
NFData CalendarDiffDays
Instance details Defined in Data.Time.Calendar.CalendarDiffDays Methods rnf :: CalendarDiffDays -> () #
Eq CalendarDiffDays
Instance details Defined in Data.Time.Calendar.CalendarDiffDays Methods (==) :: CalendarDiffDays -> CalendarDiffDays -> Bool # (/=) :: CalendarDiffDays -> CalendarDiffDays -> Bool #
ISO8601 CalendarDiffDays	`PyYmMdD` (ISO 8601:2004(E) sec. 4.4.3.2)
Instance details Defined in Data.Time.Format.ISO8601 Methods iso8601Format :: Format CalendarDiffDays #
Lift CalendarDiffDays Source #
Instance details Defined in Data.Time.Orphans Methods lift :: Quote m => CalendarDiffDays -> m Exp # liftTyped :: forall (m :: Type -> Type). Quote m => CalendarDiffDays -> Code m CalendarDiffDays #
type Rep CalendarDiffDays Source #
Instance details Defined in Data.Time.Orphans type Rep CalendarDiffDays = D1 ('MetaData "CalendarDiffDays" "Data.Time.Calendar.CalendarDiffDays" "time-1.12.2" 'False) (C1 ('MetaCons "CalendarDiffDays" 'PrefixI 'True) (S1 ('MetaSel ('Just "cdMonths") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Integer) :*: S1 ('MetaSel ('Just "cdDays") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Integer)))

calendarDay :: CalendarDiffDays #

calendarWeek :: CalendarDiffDays #

calendarMonth :: CalendarDiffDays #

calendarYear :: CalendarDiffDays #

scaleCalendarDiffDays :: Integer -> CalendarDiffDays -> CalendarDiffDays #

Scale by a factor. Note that scaleCalendarDiffDays (-1) will not perfectly invert a duration, due to variable month lengths.

Year, month and day

type Year = Integer #

Year of Common Era (when positive).

pattern CommonEra :: Integer -> Year #

Also known as Anno Domini.

pattern BeforeCommonEra :: Integer -> Year #

Also known as Before Christ. Note that Year 1 = 1 CE, and the previous Year 0 = 1 BCE. CommonEra and BeforeCommonEra form a COMPLETE set.

type MonthOfYear = Int #

Month of year, in range 1 (January) to 12 (December).

pattern January :: MonthOfYear #

pattern February :: MonthOfYear #

pattern March :: MonthOfYear #

pattern April :: MonthOfYear #

pattern May :: MonthOfYear #

pattern June :: MonthOfYear #

pattern July :: MonthOfYear #

pattern August :: MonthOfYear #

pattern September :: MonthOfYear #

pattern October :: MonthOfYear #

pattern November :: MonthOfYear #

pattern December :: MonthOfYear #

The twelve MonthOfYear patterns form a COMPLETE set.

type DayOfMonth = Int #

Day of month, in range 1 to 31.

Gregorian calendar

toGregorian :: Day -> (Year, MonthOfYear, DayOfMonth) #

Convert to proleptic Gregorian calendar.

fromGregorian :: Year -> MonthOfYear -> DayOfMonth -> Day #

Convert from proleptic Gregorian calendar. Invalid values will be clipped to the correct range, month first, then day.

fromGregorianValid :: Year -> MonthOfYear -> DayOfMonth -> Maybe Day #

Convert from proleptic Gregorian calendar. Invalid values will return Nothing

showGregorian :: Day -> String #

Show in ISO 8601 format (yyyy-mm-dd)

gregorianMonthLength :: Year -> MonthOfYear -> DayOfMonth #

The number of days in a given month according to the proleptic Gregorian calendar.

addGregorianMonthsClip :: Integer -> Day -> Day #

Add months, with days past the last day of the month clipped to the last day. For instance, 2005-01-30 + 1 month = 2005-02-28.

addGregorianMonthsRollOver :: Integer -> Day -> Day #

Add months, with days past the last day of the month rolling over to the next month. For instance, 2005-01-30 + 1 month = 2005-03-02.

addGregorianYearsClip :: Integer -> Day -> Day #

Add years, matching month and day, with Feb 29th clipped to Feb 28th if necessary. For instance, 2004-02-29 + 2 years = 2006-02-28.

addGregorianYearsRollOver :: Integer -> Day -> Day #

Add years, matching month and day, with Feb 29th rolled over to Mar 1st if necessary. For instance, 2004-02-29 + 2 years = 2006-03-01.

addGregorianDurationClip :: CalendarDiffDays -> Day -> Day #

Add months (clipped to last day), then add days

addGregorianDurationRollOver :: CalendarDiffDays -> Day -> Day #

Add months (rolling over to next month), then add days

diffGregorianDurationClip :: Day -> Day -> CalendarDiffDays #

Calendrical difference, with as many whole months as possible

diffGregorianDurationRollOver :: Day -> Day -> CalendarDiffDays Source #

Calendrical difference, with as many whole months as possible.

isLeapYear :: Year -> Bool #

Is this year a leap year according to the proleptic Gregorian calendar?

Week

data DayOfWeek #

Constructors

Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday

Instances

Instances details

Data DayOfWeek
Instance details Defined in Data.Time.Calendar.Week Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> DayOfWeek -> c DayOfWeek # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c DayOfWeek # toConstr :: DayOfWeek -> Constr # dataTypeOf :: DayOfWeek -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c DayOfWeek) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c DayOfWeek) # gmapT :: (forall b. Data b => b -> b) -> DayOfWeek -> DayOfWeek # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> DayOfWeek -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> DayOfWeek -> r # gmapQ :: (forall d. Data d => d -> u) -> DayOfWeek -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> DayOfWeek -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> DayOfWeek -> m DayOfWeek # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> DayOfWeek -> m DayOfWeek # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> DayOfWeek -> m DayOfWeek #
Enum DayOfWeek	"Circular", so for example `[Tuesday ..]` gives an endless sequence. Also: `fromEnum` gives [1 .. 7] for [Monday .. Sunday], and `toEnum` performs mod 7 to give a cycle of days.
Instance details Defined in Data.Time.Calendar.Week Methods succ :: DayOfWeek -> DayOfWeek # pred :: DayOfWeek -> DayOfWeek # toEnum :: Int -> DayOfWeek # fromEnum :: DayOfWeek -> Int # enumFrom :: DayOfWeek -> [DayOfWeek] # enumFromThen :: DayOfWeek -> DayOfWeek -> [DayOfWeek] # enumFromTo :: DayOfWeek -> DayOfWeek -> [DayOfWeek] # enumFromThenTo :: DayOfWeek -> DayOfWeek -> DayOfWeek -> [DayOfWeek] #
Ix DayOfWeek
Instance details Defined in Data.Time.Calendar.Week Methods range :: (DayOfWeek, DayOfWeek) -> [DayOfWeek] # index :: (DayOfWeek, DayOfWeek) -> DayOfWeek -> Int # unsafeIndex :: (DayOfWeek, DayOfWeek) -> DayOfWeek -> Int # inRange :: (DayOfWeek, DayOfWeek) -> DayOfWeek -> Bool # rangeSize :: (DayOfWeek, DayOfWeek) -> Int # unsafeRangeSize :: (DayOfWeek, DayOfWeek) -> Int #
Read DayOfWeek
Instance details Defined in Data.Time.Calendar.Week Methods readsPrec :: Int -> ReadS DayOfWeek # readList :: ReadS [DayOfWeek] # readPrec :: ReadPrec DayOfWeek # readListPrec :: ReadPrec [DayOfWeek] #
Show DayOfWeek
Instance details Defined in Data.Time.Calendar.Week Methods showsPrec :: Int -> DayOfWeek -> ShowS # show :: DayOfWeek -> String # showList :: [DayOfWeek] -> ShowS #
NFData DayOfWeek
Instance details Defined in Data.Time.Calendar.Week Methods rnf :: DayOfWeek -> () #
Eq DayOfWeek
Instance details Defined in Data.Time.Calendar.Week Methods (==) :: DayOfWeek -> DayOfWeek -> Bool # (/=) :: DayOfWeek -> DayOfWeek -> Bool #
Ord DayOfWeek
Instance details Defined in Data.Time.Calendar.Week Methods compare :: DayOfWeek -> DayOfWeek -> Ordering # (<) :: DayOfWeek -> DayOfWeek -> Bool # (<=) :: DayOfWeek -> DayOfWeek -> Bool # (>) :: DayOfWeek -> DayOfWeek -> Bool # (>=) :: DayOfWeek -> DayOfWeek -> Bool # max :: DayOfWeek -> DayOfWeek -> DayOfWeek # min :: DayOfWeek -> DayOfWeek -> DayOfWeek #
Hashable DayOfWeek Source #
Instance details Defined in Data.Time.Orphans Methods hashWithSalt :: Int -> DayOfWeek -> Int # hash :: DayOfWeek -> Int #
Lift DayOfWeek Source #
Instance details Defined in Data.Time.Orphans Methods lift :: Quote m => DayOfWeek -> m Exp # liftTyped :: forall (m :: Type -> Type). Quote m => DayOfWeek -> Code m DayOfWeek #

dayOfWeek :: Day -> DayOfWeek #

dayOfWeekDiff :: DayOfWeek -> DayOfWeek -> Int #

dayOfWeekDiff a b = a - b in range 0 to 6. The number of days from b to the next a.

firstDayOfWeekOnAfter :: DayOfWeek -> Day -> Day #

The first day-of-week on or after some day

weekAllDays :: DayOfWeek -> Day -> [Day] #

Returns a week containing the given Day where the first day is the DayOfWeek specified.

Examples:

>>> weekAllDays Sunday (YearMonthDay 2022 02 21)
[YearMonthDay 2022 2 20 .. YearMonthDay 2022 2 26]

>>> weekAllDays Monday (YearMonthDay 2022 02 21)
[YearMonthDay 2022 2 21 .. YearMonthDay 2022 2 27]

>>> weekAllDays Tuesday (YearMonthDay 2022 02 21)
[YearMonthDay 2022 2 15 .. YearMonthDay 2022 2 21]

Since: time-1.12.2

weekFirstDay :: DayOfWeek -> Day -> Day #

Returns the first day of a week containing the given Day.

Examples:

>>> weekFirstDay Sunday (YearMonthDay 2022 02 21)
YearMonthDay 2022 2 20

>>> weekFirstDay Monday (YearMonthDay 2022 02 21)
YearMonthDay 2022 2 21

>>> weekFirstDay Tuesday (YearMonthDay 2022 02 21)
YearMonthDay 2022 2 15

Since: time-1.12.2

weekLastDay :: DayOfWeek -> Day -> Day #

Returns the last day of a week containing the given Day.

Examples:

>>> weekLastDay Sunday (YearMonthDay 2022 02 21)
YearMonthDay 2022 2 26

>>> weekLastDay Monday (YearMonthDay 2022 02 21)
YearMonthDay 2022 2 27

>>> weekLastDay Tuesday (YearMonthDay 2022 02 21)
YearMonthDay 2022 2 21

Since: time-1.12.2

Type aliases

pattern YearMonthDay :: Year -> MonthOfYear -> DayOfMonth -> Day #

Bidirectional abstract constructor for the proleptic Gregorian calendar. Invalid values will be clipped to the correct range, month first, then day.