stagen-0.2.1: library/Stagen/Date.hs

module Stagen.Date where

import Data.Functor (void)
import Data.Time.Clock
import Data.Time.Calendar
import Text.Parsec
import Text.Parsec.String

data Date = Date {
    dateYear :: Int,
    dateMonth :: Int,
    dateDay :: Int
} deriving (Show, Eq, Ord)

datePrefix :: Parser Date
datePrefix = do
    year <- number
    void $ char '-'
    month <- number
    void $ char '-'
    day <- number
    void $ char '-'
    return (Date year month day)
 where
    number = fmap read (many1 digit)

showTwoDigits :: (Show a, Num a, Ord a) => a -> String
showTwoDigits n
    | n < 10 = '0' : show n
    | otherwise = show n

dateToUTCTime :: Date -> UTCTime
dateToUTCTime Date{dateYear,dateMonth,dateDay} = UTCTime (fromGregorian (fromIntegral dateYear) dateMonth dateDay) 0