NAME Class::Date - Class for easy date and time manipulation SYNOPSIS use Class::Date qw(date localdate gmdate now); # creating absolute date object (local time) $date = new Class::Date [$year,$month,$day,$hour,$min,$sec]; $date = date [$year,$month,$day,$hour,$min,$sec]; # "date" is an exportable function, the same as Class::Date->new $date = date { year => $year, month => $month, day => $day, hour => $hour, min => $min, sec => $sec }; $date = date "2001-11-12 07:13:12"; $date = localdate "2001-12-11"; $date = now; # the same as date(time) ... # creating absolute date object (GMT) $date = new Class::Date [$year,$month,$day,$hour,$min,$sec],1; $date = gmtime "2001-11-12 17:13"; ... # creating relative date object # (normally you don't need to create this object explicitly) $reldate = new Class::Date::Rel "3Y 1M 3D 6h 2m 4s"; $reldate = new Class::Date::Rel "6Y"; $reldate = new Class::Date::Rel $secs; # secs $reldate = new Class::Date::Rel [$year,$month,$day,$hour,$min,$sec]; $reldate = new Class::Date::Rel { year => $year, month => $month, day => $day, hour => $hour, min => $min, sec => $sec }; $reldate = new Class::Date::Rel "2001-11-12 07:13:12"; $reldate = new Class::Date::Rel "2001-12-11"; # getting values of an absolute date object $date; # prints the date in default output format (see below) $date->year; # year, e.g: 2001 $date->_year; # year - 1900, e.g. 101 $date->yr; # 2-digit year 0-99, e.g 1 $date->mon; # month 1..12 $date->month; # same as prev. $date->_mon; # month 0..11 $date->_month; # same as prev. $date->day; # day of month $date->mday; # day of month $date->day_of_month;# same as prev. $date->hour; $date->min; $date->minute; # same as prev. $date->sec; $date->second; # same as prev. $date->wday; # 1 = Sunday $date->_wday; # 0 = Sunday $date->day_of_week; # same as prev. $date->yday; $date->day_of_year; # same as prev. $date->isdst; # DST? $date->daylight_savings; # same as prev. $date->epoch; # UNIX time_t $date->monname; # name of month, eg: March $date->monthname; # same as prev. $date->wdayname; # Thursday $date->day_of_weekname # same as prev. $date->hms # 01:23:45 $date->ymd # 2000/02/29 $date->mdy # 02/29/2000 $date->dmy # 29/02/2000 $date->string # 2000-02-29 12:21:11 (format can be changed, look below) "$date" # same as prev. $date->tzoffset # timezone-offset $date->strftime($format) # POSIX strftime (without the huge POSIX.pm) ($year,$month,$day,$hour,$min,$sec)=$date->array; ($year,$month,$day,$hour,$min,$sec)=@{ $date->aref }; ($sec,$min,$hour,$day,$mon,$year,$wday,$yday,$isdst)=$date->struct; ($sec,$min,$hour,$day,$mon,$year,$wday,$yday,$isdst)=@{ $date->sref }; $hash=$date->href; print $hash->{year}."-".$hash->{month}. ... $hash->{sec} ... ; %hash=$date->hash; $date->month_begin # First day of the month (date object) $date->month_end # Last day of the month $date->days_in_month # 28..31 # date format changes { local $Class::Date::DATE_FORMAT="%Y%m%d%H%M%S"; print $date # result: 20011222000000 $Class::Date::DATE_FORMAT=undef; print $date # result: Thu Oct 13 04:54:34 1994 $Class::Date::DATE_FORMAT="%Y/%m/%d" print $date # result: 1994/10/13 } # adjusting DST in calculations (see the doc) $Class::Date::DST_ADJUST = 1; # this is the default $Class::Date::DST_ADJUST = 0; # "month-border adjust" flag $Class::Date::MONTH_BORDER_ADJUST = 0; # this is the default print date("2001-01-31")+'1M'; # will print 2001-03-03 $Class::Date::MONTH_BORDER_ADJUST = 1; print date("2001-01-31")+'1M'; # will print 2001-02-28 # getting values of a relative date object $reldate; # reldate in seconds (assumed 1 month = 2_629_744 secs) $reldate->year; $reldate->mon; $reldate->month; # same as prev. $reldate->day; $reldate->hour; $reldate->min; $reldate->minute; # same as prev. $reldate->sec; # same as $reldate $reldate->second; # same as prev. $reldate->sec_part; # "second" part of the relative date $reldate->mon_part; # "month" part of the relative date # arithmetic with dates: print date([2001,12,11,4,5,6])->truncate; # will print "2001-12-11" $new_date = $date+$reldate; $date2 = $date+'3Y 2D'; # 3 Years and 2 days $date3 = $date+[1,2,3]; # $date plus 1 year, 2 months, 3 days $date4 = $date+'3-1-5' # $date plus 3 years, 1 months, 5 days $new_date = $date-$reldate; $date2 = $date-'3Y'; # 3 Yearss $date3 = $date-[1,2,3]; # $date minus 1 year, 2 months, 3 days $date4 = $date-'3-1-5' # $date minus 3 years, 1 month, 5 days $new_reldate = $date1-$date2; $reldate2 = Class::Date->new('2000-11-12')-'2000-11-10'; $reldate3 = $date3-'1977-11-10'; $days_between = (Class::Date->new('2001-11-12')-'2001-07-04')->day; # comparison between absolute dates print $date1 > $date2 ? "I am older" : "I am younger"; # comparison between relative dates print $reldate1 > $reldate2 ? "I am faster" : "I am slower"; # Adding / Subtracting months and years are sometimes tricky: print date("2001-01-29") + '1M' - '1M'; # gives "2001-02-01" print date("2000-02-29") + '1Y' - '1Y'; # gives "2000-03-01" DESCRIPTION This module is intended to provide a general-purpose date and datetime type for perl. You have a Class::Date class for absolute date and datetime, and have a Class::Date::Rel class for relative dates. You can use "+", "-", "<" and ">" operators as with native perl data types. USAGE If you want to use a date object, you need to do the following: - create a new object - do some operations (+, -, comparison) - get result back Creating a new date object You can create a date object by the "date", "localdate" or "gmdate" function, or by calling the Class::Date constructor. "date" and "Class::Date->new" are equivalent, both has two arguments: The date and if the second argument is true then the date interpreted as GMT not local. $date1= date [2000,11,12]; $date2= Class::Date->new([2000,06,11,13,11,22],1); "localdate $x" is equivalent to "date $x", "gmdate $x" is equivalent to "date $x,1": $date1= localdate [2000,11,12]; $date2= gmdate [2000,4,2,3,33,33]; $date = localdate(time); The format of the accepted input date can be: [$year,$month,$day,$hour,$min,$sec] An array reference with 6 elements. The missing elements have default values (year: 2000, month, day: 1, hour, min, sec: 0) { year => $year, month => $month, day => $day, hour => $hour, min => $min, sec => $sec } A hash reference with the same 6 elements as above. "YYYYMMDDhhmmss" A mysql-style timestamp value, which consist of at least 14 digit. "973897262" A valid 32-bit integer: This is parsed as a unix time. "YYYY-MM-DD hh::mm:ss" A standard ISO date format. Additional ".fraction" part is ignored, ":ss" can be omitted. additional input formats You can specify "-DateParse" as an import parameter, e.g: use Class::Date qw(date -DateParse); With this, the module will try to load Date::Parse module, and if it find it then all these formats can be used as an input. Please refer to the Date::Parse documentation (this part is not tested by the author but is reported to work). Operations addition You can add the following to a Class::Date object: - a valid Class::Date::Rel object - anything, that can be used for creating a new Class::Date::Rel object It means that you don't need to create a new Class::Date::Rel object every time when you add something to the Class::Date object, it creates them automatically: $date= Class::Date->new('2001-12-11')+Class::Date::Rel->new('3Y'); is the same as: $date= date('2001-12-11')+'3Y'; You can provide a Class::Date::Rel object in the following form: array ref The same format as seen in Class::Date format, except the default values are different: all zero. hash ref The same format as seen in Class::Date format, except the default values are different: all zero. "973897262" A valid 32-bit integer is parsed as seconds. "YYYY-MM-DD hh::mm:ss" A standard ISO date format, but this is parsed as relative date date and time, so month, day and year can be zero (and defaults to zero). "12Y 6M 6D 20h 12m 5s" This special string can be used if you don't want to use the ISO format. This string consists of whitespace separated tags, each tag consists of a number and a unit. The units can be: Y: year M: month D: day h: hour m: min s: sec The number and unit must be written with no space between them. substraction The same rules are true for substraction, except you can substract two Class::Date object from each other, and you will get a Class::Date::Rel object: $reldate=$date1-$date2; $reldate=date('2001-11-12 12:11:07')-date('2001-10-07 10:3:21'); In this case, the "month" field of the $reldate object will be 0, and the other fields will contain the difference between two dates; comparison You can compare two Class::Date objects, or one Class::Date object and another data, which can be used for creating a new Class::Data object. It means that you don't need to bless both objects, one of them can be a simple string, array ref, hash ref, etc (see how to create a date object). if ( date('2001-11-12') > date('2000-11-11') ) { ... } or if ( date('2001-11-12') > '2000-11-11' ) { ... } truncate You can chop the time value from this object (set hour, min and sec to 0) with the "truncate" or "trunc" method. It does not modify the specified object, it returns with a new one. Operations with Class::Date::Rel The Class::Date::Rel object consists of a month part and a day part. Most people only use the "day" part of it. If you use both part, then you can get these parts with the "sec_part" and "mon_part" method. If you use "sec", "month", etc. methods or if you use this object in a mathematical conent, then this object is converted to one number, which is interpreted as second. The conversion is based on a 30.436 days month. Don't use it too often, because it is confusing... If you use Class::Date::Rel in an expression with other Class::Date or Class::Date::Rel objects, then it does what is expected: date('2001-11-12')+'1M' will be '2001-12-12' and date('1996-02-11')+'2M' will be '1996-04-11' Accessing data from a Class::Date and Class::Date::Rel object You can use the methods methods described at the top of the document if you want to access parts of the data which is stored in a Class::Date and Class::Date::Rel object. DST_ADJUST $DST_ADJUST is an importable variable, and is a very important configuration option. If it is set to true (default), then it adjusts the date and time when the operation switches the border of DST. You will see the difference if you run this code: $Class::Date::DST_ADJUST=0; for (my $date=localdate("2000-06-11");$date<"2001-4-5";$date+='1D') { print $date."\n"; } $Class::Date::DST_ADJUST=1; for (my $date=localdate("2000-06-11");$date<"2001-4-5";$date+='1D') { print $date."\n"; } MONTHS AND YEARS If you add or subtract "months" and "years" to a date, you may get wrong dates, e.g when you add one month to 2001-01-31, you expect to get 2001-02-31, but this date is invalid and converted to 2001-03-03. Thats' why date("2001-01-31") + '1M' - '1M' != "2001-01-31" This problem can occur only with months and years, because others can easily be converted to seconds. MONTH_BORDER_ADJUST $MONTH_BORDER_ADJUST variable is used to switch on or off the month-adjust feature. This is used only when someone adds months or years to a date and then the resulted date became invalid. An example: adding one month to "2001-01-31" will result "2001-02-31", and this is an invalid date. When $MONTH_BORDER_ADJUST is false, this result simply normalized, and becomes "2001-03-03". This is the default behaviour. When $MONTH_BORDER_ADJUST is true, this result becomes "2001-02-28". So when the date overflows, then it returns the last day insted. Both settings keeps the time information. INTERNALS This module uses operator overloading very heavily. I've found it quite stable, but I am afraid of it a bit. A Class::Date object is an array reference. A Class::Date::Rel object is an array reference, which contains month and second information. I need to store it as an array ref, because array and month values cannot be converted into seconds, because of our super calendar. You can add code references to the @Class::Date::NEW_FROM_SCALAR and @Class::Date::Rel::NEW_FROM_SCALAR. These arrays are iterated through when a scalar-format date must be parsed. These arrays only have one or two values at initialization. The parameters which the code references got are the same as the "new" method of each class. In this way, you can personalize the date parses as you want. As of 0.90, the Class::Date has been rewritten. A lot of code and design decision has been borrowed from Matt Sergeant's Time::Object, and there will be some incompatibility with the previous public version (0.5). I tried to keep compatibility methods in Class::Date. If you have problems regarding this, please drop me an email with the description of the problem, and I will set the compatibility back. As of 0.90 this code is in alpha status, and I want to release the beta versions (0.91-) soon, and then I want to release the version 1.0 if no bugs can be found in that period. DEVELOPMENT FOCUS The first goal when I have developed this module is to make this module very easy to use. The second most important goal was to make it full-featured. The third most important goal was to make it work everywhere. The only issue with this was the 'strftime("%s")' problem, I hope it has been solved. The fourth most important goal was to make it use as low memory as possible. It is an issue if someone runs this module under mod_perl. I hope all these goals can be reached by the 1.0 release. Speed was not an issue until 1.0, because people usually do not need to do tons of date manipulations in a short time. SPEED ISSUES There are two kind of adjustment in this module, DST_ADJUST and MONTH_BORDER_ADJUST. Both of them makes the "+" and "-" operations slower. If you don't need them, switch them off to achieve faster calculations. In general, if you really need fast date and datetime calculation, don't use this module. As you see in the previous section, the focus of development is not the speed until 1.0. For fast date and datetime calculations, use Date::Calc instead. BUGS * This module uses the POSIX functions (but not the POSIX module) for date and time calculations, so it is not working for dates beyond 2038 and before 1902. I hope that someone will fix this with new time_t in libc. If you really need dates over 2038, you need to completely rewrite this module or use Date::Calc or other date modules. COPYRIGHT Copyright (c) 2001 Szabó, Balázs (dLux) All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. Portions Copiright (c) Matt Sergeant AUTHOR dLux (Szabó, Balázs) CREDITS - Matt Sergeant (Lots of code are borrowed from the Time::Object module) - Tatsuhiko Miyagawa (bugfixes) SEE ALSO perl, Date::Calc, Time::Object.