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 date 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
Date::Manip::Lang::<Language>
- a description of the parseable
words in a language (see
Date::Manip::Lang for the list
of languages)
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@cpan.org)