hourglass

Hourglass is a simple time library.

Documentation: hourglass on hackage

Design

One of the key design are the Timeable and Time type classes. Time representation of the same time value are interchangeable and easy to convert between each other. This also allow the user to define new time types that interact with the same functions as the built-in types.

For example:

let dateTime0 = DateTime { dtDate = Date { dateYear = 1970, dateMonth = January, dateDay = 1 }
                         , dtTime = TimeOfDay {todHour = 0, todMin = 0, todSec = 0, todNSec = 0 } }
    elapsed0 = Elasped 0

> timeGetElapsed elapsed0 == timeGetElapsed dateTime0
True
> timeGetDate elapsed0 == timeGetDate dateTime0
True
> timePrint "YYYY-MM" elapsed0
"1970-01"
> timePrint "YYYY-MM" dateTime0
"1970-01"

Hourglass has the same limitation as your system:

• On 32 bit linux, you can't get a date after the year 2038.
• In Windows 7, you can't get the date before the year 1601.

Comparaison with time

• getting posix time:

  ------- with time import Data.Time.Clock.POSIX ptime <- getPOSIXTime

  ------- with hourglass import System.Hourglass ptime <- timeCurrent

• getting current date year:

  ------- with time import Data.Time.Clock import Data.Time.Calendar currentYear <- ((y,,) -> y) . toGregorian . utcDay <$> getCurrentTime

  ------- with hourglass import System.Hourglass import Data.Time currentYear <- dateYear . timeGetDate <$> timeCurrent

• creating a time representation of "4th May 1970 15:12:24"

  ------- with time import Data.Time.Clock import Date.Time.Calendar

  let day = fromGregorian 1970 5 4 diffTime = secondsToDiffTime (15 * 3600 + 12 * 60 + 24) in UTCTime day diffTime

  ------- with hourglass import Date.Time

  DateTime (Date 1970 May 4) (TimeOfDay 15 12 24 0)