Safe Haskell | Safe |
---|---|
Language | Haskell2010 |
System.Time.Extra
Description
Extra functions for working with times. Unlike the other modules in this package, there is no
corresponding System.Time
module. This module enhances the functionality
from Data.Time.Clock, but in quite different ways.
Throughout, time is measured in Seconds
, which is a type alias for Double
.
Documentation
Sleep for a number of seconds.
fmap (round . fst) (duration $ sleep 1) == return 1
timeout :: Seconds -> IO a -> IO (Maybe a)
A version of timeout
that takes Seconds
and never
overflows the bounds of an Int
. In addition, the bug that negative
timeouts run for ever has been fixed.
timeout (-3) (print 1) == return Nothing timeout 0.1 (print 1) == fmap Just (print 1) timeout 0.1 (sleep 2 >> print 1) == return Nothing do (t, _) <- duration $ timeout 0.1 $ sleep 1000; return $ t < 1
subtractTime :: UTCTime -> UTCTime -> Seconds
Calculate the difference between two times in seconds. Usually the first time will be the end of an event, and the second time will be the beginning.
\a b -> a > b ==> subtractTime a b > 0
showDuration :: Seconds -> String
Show a number of seconds, typically a duration, in a suitable manner with responable precision for a human.
showDuration 3.435 == "3.44s" showDuration 623.8 == "10m24s" showDuration 62003.8 == "17h13m" showDuration 1e8 == "27777h47m"
offsetTime :: IO (IO Seconds)
Call once to start, then call repeatedly to get the elapsed time since the first
call. Values will usually increase, unless the system clock is updated
(if you need the guarantee, see offsetTimeIncrease
).
offsetTimeIncrease :: IO (IO Seconds)
Like offsetTime
, but results will never decrease (though they may stay the same).
do f <- offsetTimeIncrease; xs <- replicateM 10 f; return $ xs == sort xs