Editor3rdLimit.hs

{-# LANGUAGE FlexibleContexts, FlexibleInstances
  , MultiParamTypeClasses, TemplateHaskell
  , TypeSynonymInstances, UndecidableInstances #-}

module Editor3rdLimit where

import Entry1st

import Graphics.UI.AF.WxFormAll

$(derive [''Entry,''Time,''Month])

main = startWx "Editor3rd" $ editFile specLocation ([]::HCron)

instance TypePresentation (Entry Time) tp1 tp2 tp3 tp4 tp5 where
    mkCom x = limit timeLimit ("Incorrect time")
                   (defaultCom x)
        where
          timeLimit :: Entry Time -> IO Bool
          timeLimit Entry { when = Time y month d h m } = return $
            y > 1970   && y < 2100    &&
            d >= 1                    &&
            ((month == February && d <= 28)                   ||
             (month == February && d == 29 && y `mod` 4 == 0) ||
             (month `elem` [ January, March, May, July, August
                           , October, December] && d <= 30)   ||
             (month `elem` [April, June, September, November] && d <= 30)
            )                         &&
            h >= 0     && h <= 23     &&
            m >= 0     && m <= 59

instance GInstanceCreator Time where
    gGenUpTo _ = [Time 2000 January 1 10 00]