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Date::Manip(3) User Contributed Perl Documentation Date::Manip(3)
NAME
Date::Manip - Date manipulation routines
DESCRIPTION
Date::Manip is a series of modules designed to make any common date/time operation easy to
do. Operations such as comparing two times, determining a data a given amount of time
from another, or parsing international times are all easily done. It deals with time as
it is used in the Gregorian calendar (the one currently in use) with full support for time
changes due to daylight saving time.
From the very beginning, the main focus of Date::Manip has been to be able to do ANY
desired date/time operation easily. Many other modules exist which may do a subset of
these operations quicker or more efficiently, but no other module can do all of the
operations available in Date::Manip.
Since many other date/time modules exist, some of which may do the specific operation(s)
you need faster, be sure to read the section SHOULD I USE DATE::MANIP in the
Date::Manip::Misc document before deciding which of the Date and Time modules from CPAN is
for you. However, if you want one module to do it all, Date::Manip is the one to use.
Date::Manip has functionality to work with several fundamental types of data.
dates
The word date is used extensively here and is somewhat misleading. In Date::Manip, a
date consists of three pieces of information: a calendar date, a time of day, and time
zone information. Calendar dates and times are fully handled. Time zones are handled
as well, but depending on how you use Date::Manip, there may be some limitations as
discussed below.
delta
A delta is an amount of time (i.e. the amount of time between two different dates). A
delta refers only to an amount of time. It includes no information about a starting or
ending date/time. Most people will think of a delta as an amount of time, but the
term 'time' is already used so much in this module that I didn't want to use it here
in order to avoid confusion.
recurrence
A recurring event is something which occurs on a regular recurring basis.
holidays and events
Holidays and events are basically named dates or recurrences.
Among other things, Date::Manip allow you to:
* Enter a date in practically any format you choose.
* Compare two dates, entered in widely different formats to determine which is earlier.
* Extract any information you want from a date using a format string similar to the Unix
date command.
* Determine the amount of time between two dates, or add an amount of time to a date to
get a second date.
* Work with dates with dates using international formats (foreign month names, 12/10/95
referring to October rather than December, etc.).
* To find a list of dates where a recurring event happens.
Each of these tasks is trivial (one or two lines at most) with this package.
VERSION 5 AND VERSION 6
Date::Manip version 6.00 was a complete rewrite of the module (for more information,
please refer to the Date::Manip::Changes5to6 document). The rewrite made use of features
introduced in perl 5.10 which made the date parsing routines significantly more robust.
However, since not everyone has access to a new version of perl where Date::Manip is
needed, the Date::Manip distribution actually includes two different versions of the
module. It includes the older (5.xx) release and the newer (6.xx) release.
In addition, the 6.xx release was written with both a functional and an object-oriented
interface, so there are actually three different ways to use Date::Manip (though only one
is available if you have a version of perl older than 5.10).
For those who still run an older version of perl, the 5.xx functional interface is still
available. It is known to work with perl 5.6 (and probably works with even older versions
of perl). There are some limitations to this as described below.
Version 6.xx was rewritten as a series of object-oriented modules, but a functional
interface (which is mostly backward compatible with the version 5 functional interface) is
included. The functional interface is simply wrapper functions which call the OO modules.
A more detailed description of each interface is included below (to help you decide which
interface is right for you). If you already know which interface you want to use, just go
to the SEE ALSO section below for instructions on using each interface.
It should be noted that all three interfaces will be installed, but they will only all be
usable with a recent version of perl.
FUNCTIONAL INTERFACE (VERSION 5)
When using a version of perl older than 5.10, this is the only interface available. This
interface is documented in the Date::Manip::DM5 document. This interface has several
weaknesses that need to be understood when using it:
Limited Support
The version 5 functional interface is no longer being developed, and only limited
support is available for it.
As of December 2012, no development will be done, and I will not correct any remaining
bugs in version 5. If a patch is supplied by someone else to fix bugs, I will apply
it, provided it applies cleanly, and the resulting code continues to pass all tests.
I will not apply patches to add features.
I will continue to distribute version 5 for several years. I do not have a date in
mind where version 5 will be removed.
Limited Time Zone Support
Time zone support is extremely limited, and is often broken. The lack of good time
zone support was the primary reason for rewriting Date::Manip .
Time zone information for 5.xx is now automatically generated from the 6.xx time zone
list, and every time time zones are updated in 6.xx, the 5.xx release will be
similarly updated.
Prior to the release of 6.00, time zones were added manually to Date::Manip upon
request. Since time zone information in 5.xx is now automatically generated, I no
longer take requests for time zones.
The version 5 interface does not handle daylight saving time changes properly.
Performance Issues
Considerable time has been spent speeding up Date::Manip, and fairly simple benchmarks
show that version 6 is around twice as fast as version 5.
Feel free to email me concerns and comments.
FUNCTIONAL INTERFACE (VERSION 6)
The version 6 functional interface is almost completely identical to the version 5
functional interface, except that it uses the object-oriented modules to do all the real
work.
Time zone support is greatly improved, but is still somewhat limited. Since the version 6
interface is backward compatible, dates do not store time zone information in them, so the
programmer is responsible for keeping track of what time zone each date is in. If you want
full access to the time zone support offered in Date::Manip, you have to use the object-
oriented interface.
For the most part, scripts written for older versions of Date::Manip will continue to work
(and scripts written for the version 6 functional interface will run with the version 5
interface), however in a few cases, you may need to modify your scripts. Please refer to
the Date::Manip::Migration5to6 document for a list of changes which may be necessary.
OBJECT-ORIENTED INTERFACE
As of 6.00, Date::Manip consists of a set of OO modules. Each have their own document (see
the SEE ALSO section below).
The OO interface consists of the following modules: Date::Manip::Date, Date::Manip::Delta,
Date::Manip::Recur, Date::Manip::TZ, and Date::Manip::Base .
The object-oriented interface is the only way to get the full functionality of
Date::Manip. It fully support time zones (and daylight saving time).
SELECTING AN INTERFACE
If you are running an older version of perl, the version 5 functional interface is the
only one available to you, and it will automatically be used.
If you are running a newer version of perl (5.10 or higher), you can use the object-
oriented modules by loading them directly, or you can use a functional interface.
If you use a functional interface, it will default to the version 6 interface, but you can
choose to run the version 5 interface in one of three ways:
Use the default functional interface
By including:
use Date::Manip;
in your script, one of the functional interfaces will be loaded. If you are running a
version of perl older than 5.10, it will automatically be the version 5 interface. If
you are running a newer version of perl, it will automatically load the version 6
interface.
DATE_MANIP ENVIRONMENT VARIABLE
By setting the DATE_MANIP environment variable to 'DM5' before running the perl
script, the version 5 interface will be used.
Date::Manip::Backend VARIABLE
Alternately, you can set the Date::Manip::Backend variable to be 'DM5' before loading
the module. Typically, this will be done in the following way:
BEGIN {
$Date::Manip::Backend = 'DM5';
}
use Date::Manip;
Once a functional interface is loaded, you cannot switch between the version 5 and version
6 interfaces.
SEE ALSO
The following documents describe various parts of Date::Manip. The following documents
describe the basic operation of the Date::Manip package:
A description of the functional interfaces:
Date::Manip::DM5 - the version 5 functional interface
Date::Manip::DM6 - the version 6 functional interface
An introduction to the Date::Manip classes used by the object-oriented interface and how
to configure them:
Date::Manip::Objects - an overview of the various
Date::Manip modules, and how
to use them
Date::Manip::Config - information for configuring
Date::Manip
The methods available in each class:
Date::Manip::Obj - base class (modules listed below
inherit the methods defined in this
class)
Date::Manip::Base - module for doing low-level date
operations
Date::Manip::TZ - module for working with time zones
Date::Manip::Date - date operations
Date::Manip::Delta - delta operations
Date::Manip::Recur - recurrence operations
Timezone information:
Date::Manip::DM5abbrevs - time zone abbreviations used in the
version 5 interface
Date::Manip::Zones - time zone data included in Date::Manip
used in the version 6 interface and
the object-oriented interface
Miscellaneous information:
Date::Manip::Calc - detailed informaion on how date
calculations are done
Date::Manip::Holidays - information on defining and using
holidays and events
Date::Manip::ConfigFile - sample config file
Date::Manip::Lang - information about the languages
supported by Date::Manip and how
to add a new language
Information about the module and administrative things:
Date::Manip::Migration5to6
- information on changes necessary
to scripts when upgrading from
5.xx to 6.xx
Date::Manip::Changes5 - change log for Date::Manip 5.xx
Date::Manip::Changes5to6- differences between version 5.xx
and 6.00 (including information
on upgrading); this contains more
details than the Migration5to6
document
Date::Manip::Changes6 - change log for Date::Manip 6.xx
Date::Manip::Misc - miscellaneous information about
Date::Manip (who should use it;
acknowledgements)
Date::Manip::Problems - common problems and instructions
for reporting bugs
Date::Manip::Examples - examples of how to use Date::Manip
LICENSE
This script is free software; you can redistribute it and/or modify it under the same
terms as Perl itself.
AUTHOR
Sullivan Beck (sbeck AT cpan.org)
perl v5.16.3 2014-06-09 Date::Manip(3)
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On Apache
Under GNU General Public License
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