Time

The Time library provides standard functionality for clock times, including timezone information. It follows RFC 1129 in its use of Coordinated Universal Time (UTC).

module Time (
 ClockTime, 
 Month(January,February,March,April,May,June,
 July,August,September,October,November,December),
 Day(Sunday,Monday,Tuesday,Wednesday,Thursday,Friday,Saturday),
CalendarTime(CalendarTime, ctYear, ctMonth, ctDay, ctHour, ctMin,
 ctPicosec, ctWDay, ctYDay, ctTZName, ctTZ, ctIsDST),
TimeDiff(TimeDiff, tdYear, tdMonth, tdDay, 
 tdHour, tdMin, tdSec, tdPicosec),
 getClockTime, addToClockTime, diffClockTimes,
 toCalendarTime, toUTCTime, toClockTime,
 calendarTimeToString, formatCalendarTime ) where
import Ix(Ix)
import Locale(TimeLocale(..),defaultTimeLocale)
import Char ( intToDigit )
data ClockTime = ... -- Implementation-dependent
instance Ord ClockTime where ...
instance Eq ClockTime where ...
data Month = January | February | March | April
 | May | June | July | August
 | September | October | November | December
 deriving (Eq, Ord, Enum, Bounded, Ix, Read, Show)
data Day = Sunday | Monday | Tuesday | Wednesday | Thursday 
 | Friday | Saturday
 deriving (Eq, Ord, Enum, Bounded, Ix, Read, Show)
data CalendarTime = CalendarTime {
 ctYear :: Int,
 ctMonth :: Month,
 ctDay, ctHour, ctMin, ctSec :: Int,
 ctPicosec :: Integer,
 ctWDay :: Day,
 ctYDay :: Int,
 ctTZName :: String,
 ctTZ :: Int,
 ctIsDST :: Bool
 } deriving (Eq, Ord, Read, Show)
data TimeDiff = TimeDiff {
 tdYear, tdMonth, tdDay, tdHour, tdMin, tdSec :: Int,
 tdPicosec :: Integer
 } deriving (Eq, Ord, Read, Show)
getClockTime :: IO ClockTime
getClockTime = ... -- Implementation-dependent
addToClockTime :: TimeDiff -> ClockTime -> ClockTime
addToClockTime td ct = ... -- Implementation-dependent
diffClockTimes :: ClockTime -> ClockTime -> TimeDiff
diffClockTimes ct1 ct2 = ... -- Implementation-dependent
toCalendarTime :: ClockTime -> IO CalendarTime
toCalendarTime ct = ... -- Implementation-dependent
toUTCTime :: ClockTime -> CalendarTime
toUTCTime ct = ... -- Implementation-dependent
toClockTime :: CalendarTime -> ClockTime
toClockTime cal = ... -- Implementation-dependent
calendarTimeToString :: CalendarTime -> String
calendarTimeToString = formatCalendarTime defaultTimeLocale "%c"
formatCalendarTime :: TimeLocale -> String -> CalendarTime -> String
formatCalendarTime l fmt ct@(CalendarTime year mon day hour min sec sdec 
 wday yday tzname _ _) =
 doFmt fmt
 where doFmt ('%':c:cs) = decode c ++ doFmt cs
 doFmt (c:cs) = c : doFmt cs
 doFmt "" = ""
 to12 :: Int -> Int
 to12 h = let h' = h `mod` 12 in if h' == 0 then 12 else h'
 decode 'A' = fst (wDays l !! fromEnum wday)
 decode 'a' = snd (wDays l !! fromEnum wday)
 decode 'B' = fst (months l !! fromEnum mon)
 decode 'b' = snd (months l !! fromEnum mon)
 decode 'h' = snd (months l !! fromEnum mon)
 decode 'C' = show2 (year `quot` 100)
 decode 'c' = doFmt (dateTimeFmt l)
 decode 'D' = doFmt "%m/%d/%y"
 decode 'd' = show2 day
 decode 'e' = show2' day
 decode 'H' = show2 hour
 decode 'I' = show2 (to12 hour)
 decode 'j' = show3 yday
 decode 'k' = show2' hour
 decode 'l' = show2' (to12 hour)
 decode 'M' = show2 min
 decode 'm' = show2 (fromEnum mon+1)
 decode 'n' = "\n"
 decode 'p' = (if hour < 12 then fst else snd) (amPm l)
 decode 'R' = doFmt "%H:%M"
 decode 'r' = doFmt (time12Fmt l)
 decode 'T' = doFmt "%H:%M:%S"
 decode 't' = "\t"
 decode 'S' = show2 sec
 decode 's' = ... -- Implementation-dependent
 decode 'U' = show2 ((yday + 7 - fromEnum wday) `div` 7)
 decode 'u' = show (let n = fromEnum wday in 
 if n == 0 then 7 else n)
 decode 'V' = 
 let (week, days) = 
 (yday + 7 - if fromEnum wday > 0 then 
 fromEnum wday - 1 else 6) `divMod` 7
 in show2 (if days >= 4 then
 week+1 
 else if week == 0 then 53 else week)
 decode 'W' = 
 show2 ((yday + 7 - if fromEnum wday > 0 then 
 fromEnum wday - 1 else 6) `div` 7)
 decode 'w' = show (fromEnum wday)
 decode 'X' = doFmt (timeFmt l)
 decode 'x' = doFmt (dateFmt l)
 decode 'Y' = show year
 decode 'y' = show2 (year `rem` 100)
 decode 'Z' = tzname
 decode '%' = "%"
 decode c = [c]
show2, show2', show3 :: Int -> String
show2 x = [intToDigit (x `quot` 10), intToDigit (x `rem` 10)]
show2' x = if x < 10 then [ ' ', intToDigit x] else show2 x
show3 x = intToDigit (x `quot` 100) : show2 (x `rem` 100)