Data.Time.Zones

Documentation

data TZ

Instances

Eq TZ

Defined in Data.Time.Zones.Types

Methods

(==) :: TZ -> TZ -> Bool

(/=) :: TZ -> TZ -> Bool

Data TZ

Defined in Data.Time.Zones.Types

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> TZ -> c TZ

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c TZ

toConstr :: TZ -> Constr

dataTypeOf :: TZ -> DataType

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c TZ)

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c TZ)

gmapT :: (forall b. Data b => b -> b) -> TZ -> TZ

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> TZ -> r

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> TZ -> r

gmapQ :: (forall d. Data d => d -> u) -> TZ -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> TZ -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> TZ -> m TZ

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> TZ -> m TZ

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> TZ -> m TZ

Read TZ

Defined in Data.Time.Zones.Types

Methods

readsPrec :: Int -> ReadS TZ

readList :: ReadS [TZ]

readPrec :: ReadPrec TZ

readListPrec :: ReadPrec [TZ]

Show TZ

Defined in Data.Time.Zones.Types

Methods

showsPrec :: Int -> TZ -> ShowS

show :: TZ -> String

showList :: [TZ] -> ShowS

Default TZ

Defined in Data.Time.Zones.Types

Methods

def :: TZ

NFData TZ

Defined in Data.Time.Zones.Types

Methods

rnf :: TZ -> ()

utcTZ :: TZ

The TZ definition for UTC.

Universal -> Local direction

diffForPOSIX :: TZ -> Int64 -> Int

Returns the time difference (in seconds) for TZ at the given POSIX time.

timeZoneForPOSIX :: TZ -> Int64 -> TimeZone

Returns the TimeZone for the TZ at the given POSIX time.

timeZoneForUTCTime :: TZ -> UTCTime -> TimeZone

Returns the TimeZone for the TZ at the given UTCTime.

utcToLocalTimeTZ :: TZ -> UTCTime -> LocalTime

Returns the LocalTime corresponding to the given UTCTime in TZ.

utcToLocalTimeTZ tz ut is equivalent to utcToLocalTime (timeZoneForPOSIX tz ut) ut except when the time difference is not an integral number of minutes

Local -> Universal direction

data LocalToUTCResult

Fully descriptive result of a LocalTime to UTCTime conversion.

In case of LTUAmbiguous the first result is always earlier than the second one. Generally this only happens during the daylight saving -> standard time transition (ie. summer -> winter). So, the first result corresponds to interpreting the LocalTime as a daylight saving time and the second result as standard time in the given location.

But, if the location had some kind of administrative time transition during which the clocks jumped back, then both results can correspond to standard times (or daylight saving times) just before and after the transition. You can always inspect the timeZoneSummerOnly field of the returned TimeZones to get an idea what kind of transition was taking place.

TODO(klao): document the LTUNone behavior.

Constructors

LTUNone

Fields

• _ltuResult :: UTCTime
• _ltuZone :: TimeZone

LTUUnique

Fields

• _ltuResult :: UTCTime
• _ltuZone :: TimeZone

LTUAmbiguous

Fields

• _ltuFirst :: UTCTime
• _ltuSecond :: UTCTime
• _ltuFirstZone :: TimeZone
• _ltuSecondZone :: TimeZone

Instances

Eq LocalToUTCResult

Defined in Data.Time.Zones

Methods

(==) :: LocalToUTCResult -> LocalToUTCResult -> Bool

(/=) :: LocalToUTCResult -> LocalToUTCResult -> Bool

Data LocalToUTCResult

Defined in Data.Time.Zones

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> LocalToUTCResult -> c LocalToUTCResult

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c LocalToUTCResult

toConstr :: LocalToUTCResult -> Constr

dataTypeOf :: LocalToUTCResult -> DataType

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c LocalToUTCResult)

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c LocalToUTCResult)

gmapT :: (forall b. Data b => b -> b) -> LocalToUTCResult -> LocalToUTCResult

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> LocalToUTCResult -> r

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> LocalToUTCResult -> r

gmapQ :: (forall d. Data d => d -> u) -> LocalToUTCResult -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> LocalToUTCResult -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> LocalToUTCResult -> m LocalToUTCResult

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> LocalToUTCResult -> m LocalToUTCResult

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> LocalToUTCResult -> m LocalToUTCResult

Read LocalToUTCResult

Defined in Data.Time.Zones

Methods

readsPrec :: Int -> ReadS LocalToUTCResult

readList :: ReadS [LocalToUTCResult]

readPrec :: ReadPrec LocalToUTCResult

readListPrec :: ReadPrec [LocalToUTCResult]

Show LocalToUTCResult

Defined in Data.Time.Zones

Methods

showsPrec :: Int -> LocalToUTCResult -> ShowS

show :: LocalToUTCResult -> String

showList :: [LocalToUTCResult] -> ShowS

NFData LocalToUTCResult

Defined in Data.Time.Zones

Methods

rnf :: LocalToUTCResult -> ()

localTimeToUTCFull :: TZ -> LocalTime -> LocalToUTCResult

localTimeToUTCTZ :: TZ -> LocalTime -> UTCTime

data FromLocal

Internal representation of LocalTime -> UTCTime conversion result:

Constructors

FLGap

Fields

• _flIx :: !Int
• _flRes :: !Int64

FLUnique

Fields

• _flIx :: !Int
• _flRes :: !Int64

FLDouble

Fields

• _flIx :: !Int
• _flRes1 :: !Int64
• _flRes2 :: !Int64

Instances

Eq FromLocal

Defined in Data.Time.Zones

Methods

(==) :: FromLocal -> FromLocal -> Bool

(/=) :: FromLocal -> FromLocal -> Bool

Data FromLocal

Defined in Data.Time.Zones

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> FromLocal -> c FromLocal

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c FromLocal

toConstr :: FromLocal -> Constr

dataTypeOf :: FromLocal -> DataType

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c FromLocal)

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c FromLocal)

gmapT :: (forall b. Data b => b -> b) -> FromLocal -> FromLocal

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> FromLocal -> r

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> FromLocal -> r

gmapQ :: (forall d. Data d => d -> u) -> FromLocal -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> FromLocal -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> FromLocal -> m FromLocal

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> FromLocal -> m FromLocal

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> FromLocal -> m FromLocal

Read FromLocal

Defined in Data.Time.Zones

Methods

readsPrec :: Int -> ReadS FromLocal

readList :: ReadS [FromLocal]

readPrec :: ReadPrec FromLocal

readListPrec :: ReadPrec [FromLocal]

Show FromLocal

Defined in Data.Time.Zones

Methods

showsPrec :: Int -> FromLocal -> ShowS

show :: FromLocal -> String

showList :: [FromLocal] -> ShowS

NFData FromLocal

Defined in Data.Time.Zones

Methods

rnf :: FromLocal -> ()

localToPOSIX :: TZ -> Int64 -> FromLocal

Acquiring TZ information

loadTZFromFile :: FilePath -> IO TZ

Reads and parses a time zone information file (in tzfile(5) aka. Olson file format) and returns the corresponding TZ data structure.

loadTZFromDB :: String -> IO TZ

Reads the corresponding file from the time zone database shipped with this package.

loadSystemTZ :: String -> IO TZ

Looks for the time zone file in the system timezone directory, which is /usr/share/zoneinfo, or if the TZDIR environment variable is set, then there.

Note, this is unlikely to work on non-posix systems (e.g., Windows), use loadTZFromDB or loadTZFromFile instead.

loadLocalTZ :: IO TZ

Returns the local TZ based on the TZ and TZDIR environment variables.

See tzset(3) for details, but basically:

• If TZ environment variable is unset, we loadTZFromFile "/etc/localtime".
• If TZ is set, but empty, we loadSystemTZ "UTC".
• Otherwise, we just loadSystemTZ it.

Note, this means we don't support POSIX-style TZ variables (like "EST5EDT"), only those that are explicitly present in the time zone database.

Utilities

diffForAbbr :: TZ -> String -> Maybe Int

Returns a time difference (in seconds) corresponding to the abbreviation in the given time zone.

If there are multiple time differences associated with the same abbreviation, the one corresponding to the latest use is returned. (The latest use might be in the past or the future depending on whether the abbreviation is still in use.)

This function is here for informational purpose only, do not use it for time conversion. (Instead, use localTimeToUTCFull, and if the result is ambiguous disambiguate between the possible results based on the abbreviation.)