Provided by: libdate-calc-perl_6.4-2_all 
NAME
Date::Calendar::Year - Implements embedded "year" objects for Date::Calendar
MOTTO
There is more than one way to do it - this is just one of them!
PREFACE
Note that Date::Calendar::Year (and Date::Calendar) can only deal with years lying within
the range [1583..2299].
SYNOPSIS
use Date::Calendar::Year qw( check_year empty_period );
use Date::Calendar::Year qw( :all ); # same as above
check_year(YEAR|DATE); # dies if year < 1583 or year > 2299
empty_period(); # warns about empty interval if $^W is set
$index = $year->date2index(YEAR,MONTH,DAY|DATE);
$date = $year->index2date(INDEX);
use Date::Calendar::Profiles qw( $Profiles );
$year_2000_US_FL = Date::Calendar::Year->new( 2000, $Profiles->{'US-FL'} [,LANG[,WEEKEND]] );
$year_2001_DE_NW = Date::Calendar::Year->new( 2001, $Profiles->{'DE-NW'} [,LANG[,WEEKEND]] );
$year = Date::Calendar::Year->new( 2001, {} );
$year->init( 2002, $Profiles->{'DE-SN'} [,LANG[,WEEKEND]] );
$vector = $year->vec_full(); # vector of full holidays
$vector = $year->vec_half(); # vector of half holidays
$vector = $year->vec_work(); # NOT a vector of workdays but a workspace!
$size = $year->val_days(); # number of days in that year, size of vectors
$base = $year->val_base(); # number of days for [year,1,1] since [1,1,1]
$number = $year->val_year(); # the year's number itself
$number = $year->year(); # alias for val_year()
@names = $year->labels(YEAR,MONTH,DAY|DATE);
@holidays = $year->labels();
$holidays = $year->labels();
@dates = $year->search(PATTERN);
$dates = $year->search(PATTERN);
$hashref = $year->tags(YEAR,MONTH,DAY|DATE);
$hashref = $year->tags(INDEX);
$days = $year->delta_workdays(YEAR,MONTH1,DAY1|DATE1
,YEAR,MONTH2,DAY2|DATE2
,FLAG1,FLAG2);
($date,$rest,$sign) = $year->add_delta_workdays(YEAR,MONTH,DAY|DATE
,DELTA,SIGN);
$flag = $year->is_full(YEAR,MONTH,DAY|DATE);
$flag = $year->is_half(YEAR,MONTH,DAY|DATE);
$flag = $year->is_work(YEAR,MONTH,DAY|DATE);
INTERFACE
Note that whenever a year number, a date, a time or a combined date and time are expected
as input parameters by one of the methods of this class, you can always pass a
Date::Calc[::Object] date object or an array reference (of an array of appropriate length)
instead!
See Date::Calc::Object(3) for more details.
So instead of calling a given method like this:
$object->method1( $year,$month,$day );
$object->method2( $year1,$month1,$day1, $year2,$month2,$day2 );
$object->method3( $year1, $year2, $year3 );
You can also call it like so:
$object->method1( $date );
$object->method1( [1964,1,3] );
$object->method2( $year1,$month1,$day1, $date2 );
$object->method2( $date1, $year2,$month2,$day2 );
$object->method2( $date1, $date2 );
$object->method2( $year1,$month1,$day1, [2001,3,17] );
$object->method2( [1964,1,3], $year2,$month2,$day2 );
$object->method2( [1964,1,3], [2001,3,17] );
$object->method2( $date1, [2001,3,17] );
$object->method2( [1964,1,3], $date2 );
$object->method3( $year1, $date2, [2001,3,17] );
And similarly if a time or a combined date and time are expected.
If you substitute an expected year number by an anonymous array (this is the recommended
way of writing date constants, for increased readability of your programs), it must
contain three values, nevertheless (otherwise the use of an anonymous array would be
pointless).
Don't confuse year numbers and their substitutes (a date object or an array reference)
with Date::Calendar::Year objects, which are a totally different thing!
But incidentally ":-)", you may also pass a Date::Calendar::Year object whenever a year
number is expected. However, and perhaps against your expectations at times, only the year
number from that object will be used, not the year object itself (the year object in
question might be using the wrong profile!).
Moreover, whenever a method of this class returns a date, it does so by returning a
Date::Calc[::Object] date object.
IMPLEMENTATION
Each Date::Calendar::Year object consists mainly of three bit vectors, plus some
administrative attributes, all stored in a (blessed) hash.
All three bit vectors contain as many bits as there are days in the corresponding year,
i.e., either 365 or 366.
The first bit vector, called "FULL", contains set bits for Saturdays, Sundays and all
"full" legal holidays (i.e., days off, on which you usually do not work).
The second bit vector, called "HALF", contains set bits for all "half" holidays, i.e.,
holidays where you get only half a day off from work.
The third and last bit vector, called "WORK", is used as a workspace, in which various
calculations are performed throughout this module.
Its name does NOT come from "working days" (as you might think), but from "workspace".
It only so happens that it is used to calculate the working days sometimes, at some places
in this module.
But you are free to use it yourself, for whatever calculation you would like to carry out
yourself.
The two other bit vectors, "FULL" and "HALF", should never be changed, unless you know
EXACTLY what you're doing!
DESCRIPTION
Functions
• "check_year(YEAR);"
This function checks that the given year lies in the permitted range [1583..2299]. It
returns nothing in case of success, and throws an exception ("given year out of range
[1583..2299]") otherwise.
• "empty_period();"
This function issues a warning (from the perspective of the caller of a Date::* module)
that the given range of dates is empty ("dates interval is empty"), provided that
warnings are enabled (i.e., "$^W" is true).
This function is currently used by the method "delta_workdays()" in this class, and by
its equivalent from the Date::Calendar module.
It is called whenever the range of dates of which the difference in working days is to
be calculated is empty. This can happen for instance if you specify two adjacent dates
both of which are not to be included in the difference.
Methods
• "$index = $year->date2index(YEAR,MONTH,DAY|DATE);"
This method converts a given date into the number of the day in that year (this is
sometimes also referred to as the "julian" date), i.e., a number between 0 (for January
1st) and the number of days in the given year minus one, i.e., 364 or 365 (for December
31st).
You may need this in order to access the bit vectors returned by the methods
"vec_full()", "vec_half()" and "vec_work()".
Note that there are shorthand methods in this module called "is_full()", "is_half()" and
"is_work()", which serve to test individual bits of the three bit vectors which are a
part of each Date::Calendar::Year object.
An exception ("given year != object's year") is thrown if the year associated with the
year object itself and the year from the given date do not match.
An exception ("invalid date") is also thrown if the given arguments do not constitute a
valid date, or ("given year out of range [1583..2299]") if the given year lies outside
of the permitted range.
• "$date = $year->index2date(INDEX);"
This method converts an index (or "julian date") for the given year back into a date.
An exception ("invalid index") is thrown if the given index is outside of the permitted
range for the given year, i.e., "[0..364]" or "[0..365]".
Note that this method returns a Date::Calc OBJECT!
• "$year_2000_US_FL = Date::Calendar::Year->new( 2000, $Profiles->{'US-FL'}
[,LANG[,WEEKEND]] );"
"$year_2001_DE_NW = Date::Calendar::Year->new( 2001, $Profiles->{'DE-NW'}
[,LANG[,WEEKEND]] );"
"$year = Date::Calendar::Year->new( 2001, {} );"
This is the constructor method. Call it to create a new Date::Calendar::Year object.
The first argument must be a year number in the range [1583..2299].
The second argument must be the reference of a hash, which usually contains names of
holidays and commemorative days as keys and strings containing the date or formula for
each holiday as values.
Reading this hash and initializing the object's internal data is performed by an extra
method, called "init()", which is called internally by the constructor method, and which
is described immediately below, after this method.
In case you want to call the "init()" method yourself, explicitly, after creating the
object, you can pass an empty profile (e.g., just an empty anonymous hash) to the
"new()" method, in order to create an empty object, and also to improve performance.
The third argument is optional, and must consist of the valid name or number of a
language as provided by the Date::Calc(3) module, if given.
This argument determines which language shall be used when reading the profile, since
the profile may contain names of months and weekdays in its formulas in that language.
The default is English if no value or no valid value is specified (and if the global
default has not been changed with "Language()").
After the third argument, a list of day numbers which will constitute the "weekend" can
optionally be specified, where 1=Monday, 2=Tuesday, 3=Wednesday, 4=Thursday, 5=Friday,
6=Saturday and 7=Sunday.
If no values are given, 6 and 7 (Saturday and Sunday) are automatically taken as
default.
If values outside of the range 1..7 are given, they will be ignored.
This can be used to switch off this feature and to have no regularly recurring holidays
at all when for instance a zero is given.
• "$year->init( 2002, $Profiles->{'DE-SN'} [,LANG[,WEEKEND]] );"
This method is called by the "new()" constructor method, internally, and has the same
arguments as the latter.
See immediately above for a description of these arguments.
Note that you can also call this method explicitly yourself, if needed, and you can of
course subclass the Date::Calendar::Year class and override the "init()" method with a
method of your own.
The holiday scheme or "profile" (i.e., the reference of a hash passed as the second
argument to this method) must obey the following semantics and syntax:
The keys are the names of the holiday or commemorative day in question. Keys must be
unique (but see further below).
The difference between a holiday and a commemorative day is that you (usually) get a day
off on a holiday, whereas on a purely commemorative day, you don't.
A commemorative day is just a date with a name, nothing more.
The values belonging to these keys can either be the code reference of a callback
function (see Date::Calendar::Profiles(3) for more details and examples), or a string.
All other values cause a fatal error with program abortion.
The strings can specify three types of dates:
- fixed dates
(like New Year, or first of January),
- dates relative to Easter Sunday
(like Ascension = Easter Sunday + 39 days), and
- the 1st, 2nd, 3rd, 4th or last
of a given day of week in a given month
(like "the 4th Thursday of November", or Thanksgiving).
All other types of dates must be specified via callback functions.
Note that the "last" of a given day of week is written as the "5th", because the last is
always either the 5th or the 4th of the given day of week. So the "init()" module first
calculates the 5th of the requested day of week, and if that doesn't exist, takes the
4th instead.
There are also two modifier characters which may prefix the string with the date
formula, "#" and ":".
The character "#" (mnemonic: it's only a comment) signals that the date in question is a
purely commemorative day, i.e., it will not enter into any date calculations, but can be
queried with the "labels()" and "search()" methods, and appears when printing a
calendar, for instance.
The character ":" (mnemonic: divided into two halves) specifies that the date in
question is only a "half" holiday, i.e., you only get half a day off instead of a full
day. Some companies have this sort of thing. ":-)"
The exact syntax for the date formula strings is the following (by example):
- Fixed dates:
"Christmas" => "24.12", # European format (day, month)
"Christmas" => "24.12.",
"Christmas" => "24Dec",
"Christmas" => "24.Dec",
"Christmas" => "24Dec.",
"Christmas" => "24.Dec.",
"Christmas" => "24-12",
"Christmas" => "24-12-",
"Christmas" => "24-Dec",
"Christmas" => "24-Dec-",
"Christmas" => "12/25", # American format (month, day)
"Christmas" => "Dec25",
"Christmas" => "Dec/25",
- Dates relative to Easter Sunday:
"Ladies' Carnival" => "-52",
"Carnival Monday" => "-48",
"Mardi Gras" => "-47",
"Ash Wednesday" => "-46",
"Palm Sunday" => "-7",
"Maundy Thursday" => "-3",
"Good Friday" => "-2",
"Easter Sunday" => "+0",
"Easter Monday" => "+1",
"Ascension" => "+39",
"Whitsunday" => "+49",
"Whitmonday" => "+50",
"Corpus Christi" => "+60",
- The 1st, 2nd, 3rd, 4th or last day of week:
"Thanksgiving" => "4Thu11",
"Thanksgiving" => "4/Thu/Nov",
"Columbus Day" => "2/Mon/Oct",
"Columbus Day" => "2/Mon/10",
"Columbus Day" => "2/1/Oct",
"Columbus Day" => "2/1/10",
"Memorial Day" => "5/Mon/May", # LAST Monday of May
Remember that each of these date formula strings may also be prefixed with either "#" or
":":
"Christmas" => ":24.12.", # only half a day off
"Valentine's Day" => "#Feb/14", # not an official holiday
Note that the name of the month or day of week may have any length you like, it just
must specify the intended month or day of week unambiguously. So "D", "De", "Dec",
"Dece", "Decem", "Decemb", "Decembe" and "December" would all be valid, for example.
Note also that case is ignored.
When specifying day and month numbers, or offsets relative to Easter Sunday, leading
zeros are permitted (for nicely indented formatting, for instance) but ignored.
Leading zeros are not permitted in front of the ordinal number [1..5] or the number of
the day of week [1..7] when specifying the nth day of week in a month.
BEWARE that if keys are not unique in the source code, later entries will overwrite
previous ones! I.e.,
...
"My special holiday" => "01-11",
"My special holiday" => "02-11",
...
will NOT set two holidays of the same name, one on November first, the other on November
second, but only one, on November second!
Therefore, in order to use sets of defaults and to be able to override some of them, you
must FIRST include any hash containing the default definitions, and THEN write down your
own definitions (see also the Date::Calendar::Profiles module for examples of this!),
like this:
$defaults =
{
"Holiday #1" => "01-01",
"Holiday #2" => "02-02",
"Holiday #3" => "03-03"
};
$variant1 =
{
%$defaults,
"Holiday #2" => "09-02",
"Holiday #4" => "04-04"
};
This is because of the way hashes work in Perl.
The "init()" method proceeds as follows:
First it checks whether the given year number lies in the range [1583..2299]. A fatal
error occurs if not.
Then it determines the number of days in the requested year, and stores it in the given
Date::Calendar::Year object.
It then calls the Bit::Vector(3) module to allocate three bit vectors with a number of
bits equal to the number of days in the requested year, and stores the three object
references (of the bit vectors) in the Date::Calendar::Year object.
(See also the description of the three methods "vec_full()", "vec_half()" and
"vec_full()" immediately below.)
It then sets the bits which correspond to Saturdays and Sundays (or optionally to the
days whose numbers have been specified as the "weekend") in the "full holidays" bit
vector.
At last, it iterates over the keys of the given holiday scheme (of the hash referred to
by the hash reference passed to the "init()" method as the second argument), evaluates
the formula (or calls the given callback function), and sets the corresponding bit in
the "full" or "half" holidays bit vector if the calculated date is valid.
A fatal error occurs if the date formula cannot be parsed or if the date returned by a
formula or callback function is invalid (e.g. 30-Feb-2001 or the like) or lies outside
the given year (e.g. Easter+365).
Finally, the "init()" method makes sure that days marked as "full" holidays do not
appear as "half" holidays as well.
Then the "init()" method returns.
Note that when deciphering the date formulas, the "init()" method uses the functions
"Decode_Day_of_Week()" and "Decode_Month()" from the Date::Calc(3) module, which are
language-dependent.
Therefore the "init()" method allows you to pass it an optional third argument, which
must consist of the valid name or number of a language as provided by the Date::Calc(3)
module.
For the time of scanning the given holiday scheme, the "init()" method will use the
language that has been specified, or the global setting from "Language()" if no or an
invalid language parameter is given.
The default is English if none is specified and if the global setting has not been
modified.
This means that you can provide the names of months and days of week in your holiday
profile in any of the languages supported by the Date::Calc(3) module, provided you give
the "init()" method a clue (the third parameter) which language to expect.
• "$vector = $year->vec_full();"
This method returns a reference to the bit vector in the given year object which
contains all "full" holidays.
BEWARE that you should NEVER change the contents of this bit vector unless you know
EXACTLY what you're doing!
You should usually only read from this bit vector, or use it as an operand in bit vector
operations - but never as an lvalue.
• "$vector = $year->vec_half();"
This method returns a reference to the bit vector in the given year object which
contains all "half" holidays.
BEWARE that you should NEVER change the contents of this bit vector unless you know
EXACTLY what you're doing!
You should usually only read from this bit vector, or use it as an operand in bit vector
operations - but never as an lvalue.
• "$vector = $year->vec_work();"
This method returns a reference to the "workspace" bit vector in the given year object.
Note that you cannot rely on the contents of this bit vector.
You have to set it up yourself before performing any calculations with it.
Currently the contents of this bit vector are modified by the two methods
"delta_workdays()" and "add_delta_workdays()", in ways which are hard to predict
(depending on the calculations being performed).
The size of this bit vector can be determined through either ""$days =
$vector->Size();"" or ""$days = $year->val_days();"".
• "$size = $year->val_days();"
This method returns the number of days in the given year object, i.e., either 365 or
366. This is also the size (number of bits) of the three bit vectors contained in the
given year object.
• "$base = $year->val_base();"
This method returns the value of the expression ""Date_to_Days($year->val_year(),1,1)"",
or in other words, the number of days between January 1st of the year 1 and January 1st
of the given year, plus one.
This value is used internally by the method "date2index()" in order to calculate the
"julian" date or day of the year for a given date.
The expression above is computed only once in method "init()" and then stored in one of
the year object's attributes, of which this method just returns the value.
• "$number = $year->val_year();"
"$number = $year->year();"
These two methods are identical, the latter being a shortcut of the former.
They return the number of the year for which a calendar has been stored in the given
year object.
The method name "val_year()" is used here in order to be consistent with the other
attribute accessor methods of this class, and the method "year()" is necessary in order
to be able to pass Date::Calendar::Year objects as parameters instead of a year number
in the methods of the Date::Calendar and Date::Calendar::Year modules.
• "@names = $year->labels(YEAR,MONTH,DAY|DATE);"
"@holidays = $year->labels();"
"$holidays = $year->labels();"
If any arguments are given, they are supposed to represent a date. In that case, a list
of all labels (= names of holidays) associated with that date are returned. The first
item returned is always the name of the day of week for that date.
If no arguments are given, the list of all available labels in the given year is
returned. This list does NOT include any names of the days of week (which would be
pointless in this case).
In list context, the resulting list itself is returned. In scalar context, the number of
items in the resulting list is returned.
• "@dates = $year->search(PATTERN);"
"$dates = $year->search(PATTERN);"
This method searches through all the labels of the given year and returns a list of date
objects with all dates whose labels match the given pattern.
Note that this is a simple, case-insensitive substring search, NOT a full-fledged
regular expression search!
The result is guaranteed to be sorted chronologically.
In scalar context, only the number of items in the resulting list is returned, instead
of the resulting list itself (as in list context).
• "$hashref = $year->tags(YEAR,MONTH,DAY|DATE);"
"$hashref = $year->tags(INDEX);"
This method returns a hash reference for the given calendar and date (or index). The
hash it refers to is a copy of the calendar profile's internal hash which contains the
names for the given date as keys and 0, 1, 2, or 3 as their corresponding values meaning
the following:
0 => commemorative day
1 => "half" holiday
2 => "full" holiday
3 => both a "half" and a "full" holiday
The value "3" should only occur if a date has been redefined by the underlying profile
using the same key (i.e., the same name) but with a different type of holiday.
The index must be a number such as returned by the method "date2index()"; it can be used
here instead of a date or a date object in order to speed up processing (= no need to
calculate it internally).
• "$days = $year->delta_workdays(YEAR,MONTH1,DAY1, YEAR,MONTH2,DAY2, FLAG1,FLAG2);"
"$days = $year->delta_workdays(DATE1,DATE2,FLAG1,FLAG2);"
This method calculates the number of work days (i.e., the number of days, but excluding
all holidays) between two dates.
In other words, this method is equivalent to the "Delta_Days()" function of the
Date::Calc module, except that it disregards holidays in its counting.
The two flags indicate whether the start and end dates should be included in the
counting (that is, of course, only in case they aren't holidays), or not.
It is common, for example, that you want to know how many work days are left between the
current date and a given deadline.
Typically, you will want to count the current date but not the deadline's date. So you
would specify "true" ("1") for FLAG1 and "false" ("0") for FLAG2 in order to achieve
that.
In other words, a value of "true" means "including this date", a value of "false" means
"excluding this date".
As with the "Delta_Days()" function from the Date::Calc module, the dates have to be
given in chronological order to yield a positive result. If the dates are reversed, the
result will be negative.
The parameter FLAG1 is associated with the first given date, the parameter FLAG2 with
the second given date (regardless of whether the dates are in chronological order or
not).
An exception ("given year != object's year") is thrown if the year number of either of
the two given dates does not match the year number associated with the given year
object.
An exception ("invalid date") is also raised if either of the two date arguments does
not constitute a valid date.
• "($date,$rest,$sign) = $year->add_delta_workdays(YEAR,MONTH,DAY, DELTA, SIGN);"
"($date,$rest,$sign) = $year->add_delta_workdays(DATE,DELTA,SIGN);"
This method is the equivalent of the "Add_Delta_Days()" function from the Date::Calc
module, except that it adds work days and skips holidays.
In other words, you can add or subtract a number of work days "DELTA" to/from a given
date and get a new date as the result (as a Date::Calc object).
You add days (i.e., you go forward in time) with a positive offset "DELTA", and you
subtract days (i.e., you go backwards in time) with a negative offset.
Note that an exception ("invalid date") is raised if the given date argument (the
"start" date) does not constitute a valid date.
Beware that this method is limited to date calculations within a single year (in
contrast to the method with the same name from the Date::Calendar module).
Therefore, the method does not only return a date (object), but also a "rest" and a
"sign".
The "rest" indicates how many days are still left from your original DELTA after going
in the desired direction and reaching a year boundary.
The "sign" indicates in which direction (future or past) one needs to go in order to
"eat up" the "rest" (by subtracting a day from the "rest" for each work day passed), or
to adjust the resulting date (in order to skip any holidays directly after a year
boundary), if at all.
The "sign" is -1 for going backwards in time, +1 for going forward, and 0 if the result
doesn't need any more fixing (for instance because the result lies in the same year as
the starting date).
The method "add_delta_workdays()" from the Date::Calendar module uses the "rest" and
"sign" return values from this method in order to perform calculations which may cross
year boundaries.
Therefore, it is not recommended to use this method here directly, as it is rather
clumsy to use, but to use the method with the same name from the Date::Calendar module
instead, which does the same but is much easier to use and moreover allows calculations
which cross an arbitrary number of year boundaries.
BEWARE that this method may currently return unexpected (i.e., contradicting the above
documentation) or plain wrong results when going back in time (this is a bug!).
However, it works correctly and as documented above when going forward in time.
• "$flag = $year->is_full(YEAR,MONTH,DAY|DATE);"
This method returns "true" ("1") if the bit corresponding to the given date is set in
the bit vector representing "full" holidays, and "false" ("0") otherwise.
I.e., the method returns "true" if the given date is a (full) holiday (according to the
calendar profile associated with the given year object).
• "$flag = $year->is_half(YEAR,MONTH,DAY|DATE);"
This method returns "true" ("1") if the bit corresponding to the given date is set in
the bit vector representing "half" holidays, and "false" ("0") otherwise.
I.e., the method returns "true" if the given date is a half holiday (according to the
calendar profile associated with the given year object).
Note that if a date is a "full" holiday, the "half" bit is never set, even if you try to
do so in your calendar profile, on purpose or by accident.
• "$flag = $year->is_work(YEAR,MONTH,DAY|DATE);"
This method returns "true" ("1") if the bit corresponding to the given date is set in
the bit vector used to perform all sorts of calculations, and "false" ("0") otherwise.
BEWARE that the "work" in this method's name does NOT come from "work days"!
It comes from the fact that the corresponding bit vector can be used for any "work" that
you need to do. In other words, it's a "work space".
Therefore, this bit vector might contain about everything you could imagine - including
a bit pattern which marks all "work days" with set bits, if it so happens!
But you better don't rely on it, unless you put the bit pattern there yourself in the
first place.
Note that you can get a reference to this bit vector (in order to fill it with any bit
pattern you like) using the method "vec_work()", described further above in this
document.
The number of bits in this bit vector is the same as the number of days in the given
year "$year", which you can retrieve through either ""$days = $year->vec_work->Size();""
or ""$days = $year->val_days();"".
See also Bit::Vector(3) for more details.
SEE ALSO
Bit::Vector(3), Date::Calendar(3), Date::Calendar::Profiles(3), Date::Calc::Object(3),
Date::Calc(3), Date::Calc::Util(3).
KNOWN BUGS
The method "add_delta_workdays()" is known to produce results which are sometimes off by
one working day when a negative offset is used. As a workaround, try to add one working
day first and then subtract one working day more than initially intended. See also the
file "examples/bug.pl" for how to do this.
VERSION
This man page documents "Date::Calendar::Year" version 6.4.
AUTHOR
Steffen Beyer
mailto:STBEY@cpan.org
http://www.engelschall.com/u/sb/download/
COPYRIGHT
Copyright (c) 2000 - 2015 by Steffen Beyer. All rights reserved.
LICENSE
This package is free software; you can use, modify and redistribute it under the same
terms as Perl itself, i.e., at your option, under the terms either of the "Artistic
License" or the "GNU General Public License".
The C library at the core of the module "Date::Calc::XS" can, at your discretion, also be
used, modified and redistributed under the terms of the "GNU Library General Public
License".
Please refer to the files "Artistic.txt", "GNU_GPL.txt" and "GNU_LGPL.txt" in the
"license" subdirectory of this distribution for any details!
DISCLAIMER
This package is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the "GNU General Public License" for more details.