| Safe Haskell | None |
|---|
Data.Thyme.Clock
Description
Types and functions for UTC and UT1.
If you don't care about leap seconds, keep to UTCTime and
NominalDiffTime for your clock calculations, and you'll be fine.
Num, Real, Fractional and RealFrac instances for DiffTime and
NominalDiffTime are only available by importing Data.Thyme.Time. In
their stead are instances of AdditiveGroup,
HasBasis and VectorSpace, with
Scalar DiffTime ≡ Scalar
NominalDiffTime ≡ Rational
Using fromSeconds and toSeconds to convert between TimeDiffs and
other numeric types. If you really must coerce between DiffTime and
NominalDiffTime, view (microseconds . from microseconds)
UTCTime is an instance of AffineSpace, with
Diff UTCTime ≡ NominalDiffTime
UTCTime is not Y294K-compliant. Please file a bug report on GitHub when
this becomes a problem.
- data UniversalTime
- modJulianDate :: Iso' UniversalTime Rational
- data DiffTime
- data UTCTime
- data UTCView = UTCTime {
- utctDay :: !Day
- utctDayTime :: !DiffTime
- utcTime :: Iso' UTCTime UTCView
- data NominalDiffTime
- getCurrentTime :: IO UTCTime
- class (HasBasis t, Basis t ~ (), Scalar t ~ Rational) => TimeDiff t where
- microseconds :: Iso' t Int64
- toSeconds :: (TimeDiff t, Fractional n) => t -> n
- fromSeconds :: (Real n, TimeDiff t) => n -> t
- toSeconds' :: TimeDiff t => t -> Rational
- fromSeconds' :: TimeDiff t => Rational -> t
- _utctDay :: Lens' UTCTime Day
- _utctDayTime :: Lens' UTCTime DiffTime
Universal Time
data UniversalTime Source
The principal form of universal time, namely UT1.
UniversalTime is defined by the rotation of the Earth around its axis
relative to the Sun. Thus the length of a day by this definition varies
from one to the next, and is never exactly 86400 SI seconds unlike
TAI or
AbsoluteTime. The difference between UT1 and UTC is
DUT1.
Instances
modJulianDate :: Iso' UniversalTime RationalSource
View UniversalTime as a fractional number of days since the
Modified Julian Date epoch.
Absolute intervals
An absolute time interval as measured by a clock.
DiffTime forms an AdditiveGroup―so can be added using ^+^ (or ^-^
for subtraction), and also an instance of VectorSpace―so can be scaled
using *^, where
typeScalarDiffTime=Rational
Instances
UTC
Coördinated universal time:
the most common form of universal time for civil timekeeping. It is
synchronised with AbsoluteTime and both tick in increments of SI
seconds, but UTC includes occasional leap-seconds so that it does not
drift too far from UniversalTime.
UTCTime is an instance of AffineSpace, with
typeDiffUTCTime=NominalDiffTime
Use .+^ to add (or .-^ to subtract) time intervals of type
NominalDiffTime, and .-. to get the interval between UTCTimes.
Performance- Internally this is a 64-bit count of
microsecondssince the MJD epoch, so.+^,.-^and.-.ought to be fairly fast. Issues-
UTCTimecurrently cannot represent leap seconds.
Unpacked UTCTime, partly for compatibility with time.
Constructors
| UTCTime | |
Fields
| |
utcTime :: Iso' UTCTime UTCViewSource
View UTCTime as an UTCView, comprising a Day along with
a DiffTime offset since midnight.
This is an improper lens: utctDayTime offsets outside the range of
[ will carry over into the day part, with the
expected behaviour.
zeroV, posixDayLength)
data NominalDiffTime Source
A time interval as measured by UTC, that does not take leap-seconds into account.
For instance, the difference between 23:59:59 and 00:00:01 on the
following day is always 2 seconds of NominalDiffTime, regardless of
whether a leap-second took place.
NominalDiffTime forms an AdditiveGroup―so can be added using ^+^
(or ^-^ for subtraction), and also an instance of VectorSpace―so can
be scaled using *^, where
typeScalarNominalDiffTime=Rational
Instances
getCurrentTime :: IO UTCTimeSource
Get the current UTC time from the system clock.
Time interval conversion
class (HasBasis t, Basis t ~ (), Scalar t ~ Rational) => TimeDiff t whereSource
Time intervals, encompassing both DiffTime and NominalDiffTime.
Issues- Still affected by http://hackage.haskell.org/trac/ghc/ticket/7611?
Instances
toSeconds :: (TimeDiff t, Fractional n) => t -> nSource
Convert a time interval to some Fractional type.
fromSeconds :: (Real n, TimeDiff t) => n -> tSource
toSeconds' :: TimeDiff t => t -> RationalSource
Type-restricted toSeconds to avoid constraint-defaulting warnings.
fromSeconds' :: TimeDiff t => Rational -> tSource
Type-restricted fromSeconds to avoid constraint-defaulting warnings.