# Time::Piece [![CI Tests](https://github.com/Dual-Life/Time-Piece/actions/workflows/ci.yml/badge.svg?branch=master)](https://github.com/Dual-Life/Time-Piece/actions) A Perl module that replaces the standard `localtime` and `gmtime` functions with implementations that return objects. ## Documentation # NAME Time::Piece - Object Oriented time objects # SYNOPSIS use Time::Piece; my $t = localtime; print "Time is $t\n"; print "Year is ", $t->year, "\n"; # DESCRIPTION This module replaces the standard `localtime` and `gmtime` functions with implementations that return objects. It does so in a backwards compatible manner, so that using localtime/gmtime in the way documented in perlfunc will still return what you expect. The module actually implements most of an interface described by Larry Wall on the perl5-porters mailing list here: [https://www.nntp.perl.org/group/perl.perl5.porters/2000/01/msg5283.html](https://www.nntp.perl.org/group/perl.perl5.porters/2000/01/msg5283.html) # USAGE After importing this module, when you use localtime or gmtime in a scalar context, rather than getting an ordinary scalar string representing the date and time, you get a Time::Piece object, whose stringification happens to produce the same effect as the localtime and gmtime functions. There is also a new() constructor provided, which is the same as localtime(), except when passed a Time::Piece object, in which case it's a copy constructor. The following methods are available on the object: $t->sec # also available as $t->second $t->min # also available as $t->minute $t->hour # 24 hour $t->mday # also available as $t->day_of_month $t->mon # 1 = January $t->_mon # 0 = January $t->monname # Feb $t->month # same as $t->monname $t->fullmonth # February $t->year # based at 0 (year 0 AD is, of course 1 BC) $t->_year # year minus 1900 $t->yy # 2 digit year $t->wday # 1 = Sunday $t->_wday # 0 = Sunday $t->day_of_week # 0 = Sunday $t->wdayname # Tue $t->day # same as wdayname $t->fullday # Tuesday $t->yday # also available as $t->day_of_year, 0 = Jan 01 $t->isdst # also available as $t->daylight_savings $t->hms # 12:34:56 $t->hms(".") # 12.34.56 $t->time # same as $t->hms $t->ymd # 2000-02-29 $t->date # same as $t->ymd $t->mdy # 02-29-2000 $t->mdy("/") # 02/29/2000 $t->dmy # 29-02-2000 $t->dmy(".") # 29.02.2000 $t->datetime # 2000-02-29T12:34:56 (ISO 8601) $t->cdate # Tue Feb 29 12:34:56 2000 "$t" # same as $t->cdate $t->epoch # seconds since the epoch $t->tzoffset # timezone offset in a Time::Seconds object $t->julian_day # number of days since Julian period began $t->mjd # modified Julian date (JD-2400000.5 days) $t->week # week number (ISO 8601) $t->is_leap_year # true if it's a leap year $t->month_last_day # 28-31 $t->time_separator($s) # set the default separator (default ":") $t->date_separator($s) # set the default separator (default "-") $t->day_list(@days) # set the default weekdays $t->mon_list(@days) # set the default months $t->strftime(FORMAT) # same as POSIX::strftime (without the overhead # of the full POSIX extension) $t->strftime() # "Tue, 29 Feb 2000 12:34:56 GMT" Time::Piece->strptime(STRING, FORMAT) # see strptime man page. Creates a new # Time::Piece object Note that `localtime` and `gmtime` are not listed above. If called as methods on a Time::Piece object, they act as constructors, returning a new Time::Piece object for the current time. In other words: they're not useful as methods. ## Local Locales Both `wdayname` (day) and `monname` (month) allow passing in a list to use to index the name of the days against. This can be useful if you need to implement some form of localisation without actually installing or using locales. Note that this is a global override and will affect all Time::Piece instances. my @days = qw( Dimanche Lundi Merdi Mercredi Jeudi Vendredi Samedi ); my $french_day = localtime->day(@days); These settings can be overridden globally too: Time::Piece::day_list(@days); Or for months: Time::Piece::mon_list(@months); And locally for months: print localtime->month(@months); Or to populate with your current system locale call: Time::Piece->use\_locale(); ## Date Calculations It's possible to use simple addition and subtraction of objects: use Time::Seconds; my $seconds = $t1 - $t2; $t1 += ONE_DAY; # add 1 day (constant from Time::Seconds) The following are valid ($t1 and $t2 are Time::Piece objects): $t1 - $t2; # returns Time::Seconds object $t1 - 42; # returns Time::Piece object $t1 + 533; # returns Time::Piece object However adding a Time::Piece object to another Time::Piece object will cause a runtime error. Note that the first of the above returns a Time::Seconds object, so while examining the object will print the number of seconds (because of the overloading), you can also get the number of minutes, hours, days, weeks and years in that delta, using the Time::Seconds API. In addition to adding seconds, there are two APIs for adding months and years: $t = $t->add_months(6); $t = $t->add_years(5); The months and years can be negative for subtractions. Note that there is some "strange" behaviour when adding and subtracting months at the ends of months. Generally when the resulting month is shorter than the starting month then the number of overlap days is added. For example subtracting a month from 2008-03-31 will not result in 2008-02-31 as this is an impossible date. Instead you will get 2008-03-02. This appears to be consistent with other date manipulation tools. ## Truncation Calling the `truncate` method returns a copy of the object but with the time truncated to the start of the supplied unit. $t = $t->truncate(to => 'day'); This example will set the time to midnight on the same date which `$t` had previously. Allowed values for the "to" parameter are: "year", "quarter", "month", "day", "hour", "minute" and "second". ## Date Comparisons Date comparisons are also possible, using the full suite of "<", ">", "<=", ">=", "<=>", "==" and "!=". ## Date Parsing Time::Piece provides flexible date parsing via the built-in strptime() function (from FreeBSD). ### Basic Usage my $t = Time::Piece->strptime("Sunday 3rd Nov, 1943", "%A %drd %b, %Y"); print $t->strftime("%a, %d %b %Y"); Outputs: Wed, 03 Nov 1943 (see, it's even smart enough to fix my obvious date bug) ### Default Values for Partial Dates When parsing incomplete date strings, you can provide defaults for missing components: #### Supported Default Types **1. Array Reference** - Standard time components (sec, min, hour, mday, mon, year, wday, yday) (see `perldoc -f localtime`): my @defaults = localtime(); my $t = Time::Piece->strptime("15 Mar", "%d %b", { defaults => \@defaults }); **2. Hash Reference** - Specify only needed components: my $t = Time::Piece->strptime("15 Mar", "%d %b", { defaults => { year => 2023, # Years >= 1000: actual year hour => 14, # Years < 1000: offset from 1900 min => 30 } }); Valid keys: `sec`, `min`, `hour`, `mday`, `mon`, `year`, `wday`, `yday`, `isdst` **Note:** `year` in this context doesn't have to be an offset from 1900 **3. Time::Piece Object** - Copies all components including `c_islocal`: my $base = localtime(); my $t1 = Time::Piece->strptime("15 Mar", "%d %b", { defaults => $base }); # Shorthand (equivalent) my $t2 = Time::Piece->strptime("15 Mar", "%d %b", $base); #### Format String Defaults When omitted, format defaults to `"%a, %d %b %Y %H:%M:%S %Z"`: # These are equivalent: my $t1 = Time::Piece->strptime($string); my $t2 = Time::Piece->strptime($string, "%a, %d %b %Y %H:%M:%S %Z"); ### Timezone Behavior The returned object's timezone (`c_islocal`) depends on the calling context: **Default: GMT/UTC** (c\_islocal = 0) Time::Piece->strptime($string, $format) # Class method returns GMT **Local Time** (c\_islocal = 1) via: # Instance method on localtime object localtime()->strptime($string, $format) # Explicit islocal option Time::Piece->strptime($string, $format, { islocal => 1 }) # Inherited from Time::Piece defaults my $tp_obj = localtime(); Time::Piece->strptime($string, $format, $tp_obj) **Note:** Parsed values always override defaults. Only missing components use default values. For more information see "man strptime" on unix systems. Alternatively look here: [http://www.unix.com/man-page/FreeBSD/3/strftime/](http://www.unix.com/man-page/FreeBSD/3/strftime/) ### CAVEAT %A, %a, %B, %b, and friends Time::Piece::strptime by default can only parse American English date names. Meanwhile, Time::Piece->strftime() will return date names that use the current configured system locale. This means dates returned by strftime might not be able to be parsed by strptime. This is the default behavior and can be overridden by calling Time::Piece->use\_locale(). This builds a list of the current locale's day and month names which strptime will use to parse with. Note this is a global override and will affect all Time::Piece instances. For instance with a German locale: localtime->day_list(); Returns ( 'Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat' ) While: Time::Piece->use_locale(); localtime->day_list(); Returns ( 'So', 'Mo', 'Di', 'Mi', 'Do', 'Fr', 'Sa' ) ## Global Overriding Finally, it's possible to override localtime and gmtime everywhere, by including the ':override' tag in the import list: use Time::Piece ':override'; # CAVEATS ## Setting $ENV{TZ} in Threads on Win32 Note that when using perl in the default build configuration on Win32 (specifically, when perl is built with PERL\_IMPLICIT\_SYS), each perl interpreter maintains its own copy of the environment and only the main interpreter will update the process environment seen by strftime. Therefore, if you make changes to $ENV{TZ} from inside a thread other than the main thread then those changes will not be seen by strftime if you subsequently call that with the %Z formatting code. You must change $ENV{TZ} in the main thread to have the desired effect in this case (and you must also call \_tzset() in the main thread to register the environment change). Furthermore, remember that this caveat also applies to fork(), which is emulated by threads on Win32. ## Use of epoch seconds This module internally uses the epoch seconds system that is provided via the perl `time()` function and supported by `gmtime()` and `localtime()`. If your perl does not support times larger than `2^31` seconds then this module is likely to fail at processing dates beyond the year 2038. There are moves afoot to fix that in perl. Alternatively use 64 bit perl. Or if none of those are options, use the [DateTime](https://metacpan.org/pod/DateTime) module which has support for years well into the future and past. Also, the internal representation of Time::Piece->strftime deviates from the standard POSIX implementation in that is uses the epoch (instead of separate year, month, day parts). This change was added in version 1.30. If you must have a more traditional strftime (which will normally never calculate day light saving times correctly), you can pass the date parts from Time::Piece into the strftime function provided by the POSIX module (see strftime in [POSIX](https://metacpan.org/pod/POSIX) ). # AUTHOR Matt Sergeant, matt@sergeant.org Jarkko Hietaniemi, jhi@iki.fi (while creating Time::Piece for core perl) # COPYRIGHT AND LICENSE Copyright 2001, Larry Wall. This module is free software, you may distribute it under the same terms as Perl. # SEE ALSO The excellent Calendar FAQ at [http://www.tondering.dk/claus/calendar.html](http://www.tondering.dk/claus/calendar.html) # BUGS The test harness leaves much to be desired. Patches welcome. ## Development Instructions The module uses GitHub Actions for continuous integration testing across multiple platforms. ### Using Feature Branches For development and testing: 1. **Setup Git Hooks**: ```bash ./setup-hooks.sh ``` 2. **Create a feature branch**: ```bash git checkout -b feature/windows-fix ``` You can create any descriptive name after the `feature/` prefix: ```bash git checkout -b feature/memory-optimization git checkout -b feature/strawberry-perl-compatibility ``` 3. **Make your changes and commit them**: ```bash # Make changes to your code git add . git commit -m "Implement Windows-specific fixes" ``` 4. **Push to GitHub to trigger automatic tests**: ```bash git push origin feature/windows-fix ``` 5. **Delete once merge done**: ```bash # Delete locally git branch -D feature/windows-fix # Delete from GitHub git push origin --delete feature/windows-fix ``` ## Installation From CPAN: ``` cpan Time::Piece ``` From source: ``` perl Makefile.PL make make test make install ```