官方网址：http://search.cpan.org/~stbey/Date-Calc-6.3/lib/Date/Calc.pod#___top
use Date::Calc qw(Days_in_YearDays_in_MonthWeeks_in_Yearleap_yearcheck_datecheck_timecheck_business_dateDay_of_YearDate_to_DaysDay_of_WeekWeek_NumberWeek_of_YearMonday_of_WeekNth_Weekday_of_Month_YearStandard_to_BusinessBusiness_to_StandardDelta_DaysDelta_DHMSDelta_YMDDelta_YMDHMSN_Delta_YMDN_Delta_YMDHMSNormalize_DHMSAdd_Delta_DaysAdd_Delta_DHMSAdd_Delta_YMAdd_Delta_YMDAdd_Delta_YMDHMSAdd_N_Delta_YMDAdd_N_Delta_YMDHMSSystem_ClockTodayNowToday_and_NowThis_YearGmtimeLocaltimeMktimeTimezoneDate_to_TimeTime_to_DateEaster_SundayDecode_MonthDecode_Day_of_WeekDecode_LanguageDecode_Date_EUDecode_Date_USFixed_WindowMoving_WindowCompressUncompresscheck_compressedCompressed_to_TextDate_to_TextDate_to_Text_LongEnglish_OrdinalCalendarMonth_to_TextDay_of_Week_to_TextDay_of_Week_AbbreviationLanguage_to_TextLanguageLanguagesDecode_Date_EU2Decode_Date_US2Parse_DateISO_LCISO_UC);use Date::Calc qw(:all);Days_in_Year$days = Days_in_Year($year,$month);Days_in_Month$days = Days_in_Month($year,$month);Weeks_in_Year$weeks = Weeks_in_Year($year);leap_yearif (leap_year($year))check_dateif (check_date($year,$month,$day))check_timeif (check_time($hour,$min,$sec))check_business_dateif (check_business_date($year,$week,$dow))Day_of_Year$doy = Day_of_Year($year,$month,$day);Date_to_Days$days = Date_to_Days($year,$month,$day);Day_of_Week$dow = Day_of_Week($year,$month,$day);Week_Number$week = Week_Number($year,$month,$day); # DEPRECATEDWeek_of_Year($week,$year) = Week_of_Year($year,$month,$day); # RECOMMENDED$week = Week_of_Year($year,$month,$day); # DANGEROUSMonday_of_Week($year,$month,$day) = Monday_of_Week($week,$year);Nth_Weekday_of_Month_Yearif (($year,$month,$day) =Nth_Weekday_of_Month_Year($year,$month,$dow,$n))Standard_to_Business($year,$week,$dow) =Standard_to_Business($year,$month,$day);Business_to_Standard($year,$month,$day) =Business_to_Standard($year,$week,$dow);Delta_Days$Dd = Delta_Days($year1,$month1,$day1,$year2,$month2,$day2);Delta_DHMS($Dd,$Dh,$Dm,$Ds) =Delta_DHMS($year1,$month1,$day1, $hour1,$min1,$sec1,$year2,$month2,$day2, $hour2,$min2,$sec2);Delta_YMD($Dy,$Dm,$Dd) =Delta_YMD($year1,$month1,$day1,$year2,$month2,$day2);Delta_YMDHMS($D_y,$D_m,$D_d, $Dh,$Dm,$Ds) =Delta_YMDHMS($year1,$month1,$day1, $hour1,$min1,$sec1,$year2,$month2,$day2, $hour2,$min2,$sec2);N_Delta_YMD($Dy,$Dm,$Dd) =N_Delta_YMD($year1,$month1,$day1,$year2,$month2,$day2);N_Delta_YMDHMS($D_y,$D_m,$D_d, $Dhh,$Dmm,$Dss) =N_Delta_YMDHMS($year1,$month1,$day1, $hour1,$min1,$sec1,$year2,$month2,$day2, $hour2,$min2,$sec2);Normalize_DHMS($Dd,$Dh,$Dm,$Ds) =Normalize_DHMS($Dd,$Dh,$Dm,$Ds);Add_Delta_Days($year,$month,$day) =Add_Delta_Days($year,$month,$day,$Dd);Add_Delta_DHMS($year,$month,$day, $hour,$min,$sec) =Add_Delta_DHMS($year,$month,$day, $hour,$min,$sec,$Dd,$Dh,$Dm,$Ds);Add_Delta_YM($year,$month,$day) =Add_Delta_YM($year,$month,$day,$Dy,$Dm);Add_Delta_YMD($year,$month,$day) =Add_Delta_YMD($year,$month,$day,$Dy,$Dm,$Dd);Add_Delta_YMDHMS($year,$month,$day, $hour,$min,$sec) =Add_Delta_YMDHMS($year,$month,$day, $hour,$min,$sec,$D_y,$D_m,$D_d, $Dh,$Dm,$Ds);Add_N_Delta_YMD($year,$month,$day) =Add_N_Delta_YMD($year,$month,$day,$Dy,$Dm,$Dd);Add_N_Delta_YMDHMS($year,$month,$day, $hour,$min,$sec) =Add_N_Delta_YMDHMS($year,$month,$day, $hour,$min,$sec,$D_y,$D_m,$D_d, $Dhh,$Dmm,$Dss);System_Clock($year,$month,$day, $hour,$min,$sec, $doy,$dow,$dst) =System_Clock([$gmt]);Today($year,$month,$day) = Today([$gmt]);Now($hour,$min,$sec) = Now([$gmt]);Today_and_Now($year,$month,$day, $hour,$min,$sec) = Today_and_Now([$gmt]);This_Year$year = This_Year([$gmt]);Gmtime($year,$month,$day, $hour,$min,$sec, $doy,$dow,$dst) =Gmtime([time]);Localtime($year,$month,$day, $hour,$min,$sec, $doy,$dow,$dst) =Localtime([time]);Mktime$time = Mktime($year,$month,$day, $hour,$min,$sec);Timezone($D_y,$D_m,$D_d, $Dh,$Dm,$Ds, $dst) = Timezone([time]);Date_to_Time$time = Date_to_Time($year,$month,$day, $hour,$min,$sec);Time_to_Date($year,$month,$day, $hour,$min,$sec) = Time_to_Date([time]);Easter_Sunday($year,$month,$day) = Easter_Sunday($year);Decode_Monthif ($month = Decode_Month($string[,$lang]))Decode_Day_of_Weekif ($dow = Decode_Day_of_Week($string[,$lang]))Decode_Languageif ($lang = Decode_Language($string))Decode_Date_EUif (($year,$month,$day) = Decode_Date_EU($string[,$lang]))Decode_Date_USif (($year,$month,$day) = Decode_Date_US($string[,$lang]))Fixed_Window$year = Fixed_Window($yy);Moving_Window$year = Moving_Window($yy);Compress$date = Compress($year,$month,$day);Uncompressif (($century,$year,$month,$day) = Uncompress($date))check_compressedif (check_compressed($date))Compressed_to_Text$string = Compressed_to_Text($date[,$lang]);Date_to_Text$string = Date_to_Text($year,$month,$day[,$lang]);Date_to_Text_Long$string = Date_to_Text_Long($year,$month,$day[,$lang]);English_Ordinal$string = English_Ordinal($number);Calendar$string = Calendar($year,$month[,$orthodox[,$lang]]);Month_to_Text$string = Month_to_Text($month[,$lang]);Day_of_Week_to_Text$string = Day_of_Week_to_Text($dow[,$lang]);Day_of_Week_Abbreviation$string = Day_of_Week_Abbreviation($dow[,$lang]);Language_to_Text$string = Language_to_Text($lang);Language$lang = Language();Language($lang); # DEPRECATED$oldlang = Language($newlang); # DEPRECATEDLanguages$max_lang = Languages();Decode_Date_EU2if (($year,$month,$day) = Decode_Date_EU2($string[,$lang]))Decode_Date_US2if (($year,$month,$day) = Decode_Date_US2($string[,$lang]))Parse_Dateif (($year,$month,$day) = Parse_Date($string[,$lang]))ISO_LC$lower = ISO_LC($string);ISO_UC$upper = ISO_UC($string);Version$string = Date::Calc::Version();