1Pcalendar(3)          User Contributed Perl Documentation         Pcalendar(3)
2
3
4

NAME

6       Date::Pcalendar - Calendar objects for different holiday schemes
7

MOTTO

9       There is more than one way to do it - this is just one of them!
10

PREFACE

12       Basically, Date::Pcalendar is just a caching proxy class for
13       Date::Pcalendar::Year objects, which are embedded in each
14       Date::Pcalendar object.
15
16       However, and in contrast to Date::Pcalendar::Year methods,
17       Date::Pcalendar methods permit calculations spanning an arbitrary
18       number of years, without loss of efficiency.
19
20       So you should usually use Date::Pcalendar and not
21       Date::Pcalendar::Year, since that way you don't have to worry about
22       calculations crossing year boundaries.
23
24       Note however that Date::Pcalendar and Date::Pcalendar::Year can only
25       deal with years lying within the range [1583..2299].
26

SYNOPSIS

28         use Date::Pcalendar::Profiles qw( $Profiles );
29         use Date::Pcalendar;
30
31         $calendar_US_AZ  = Date::Pcalendar->new( $Profiles->{'US-AZ'} [,LANG[,WEEKEND]] );
32         $calendar_DE_SN  = Date::Pcalendar->new( $Profiles->{'DE-SN'} [,LANG[,WEEKEND]] );
33
34         $year_2000_US_AZ = $calendar_US_AZ->year( 2000 );
35         $year_2001_DE_SN = $calendar_DE_SN->year( 2001 );
36
37         @years = $calendar->cache_keys(); # returns list of year numbers
38         @years = $calendar->cache_vals(); # returns list of year objects
39
40         $calendar->cache_clr();
41         $calendar->cache_add(YEAR|DATE,...);
42         $calendar->cache_del(YEAR|DATE,...);
43
44         $index        = $calendar->date2index(YEAR,MONTH,DAY|DATE);
45
46         @names        = $calendar->labels(YEAR,MONTH,DAY|DATE);
47         @holidays     = $calendar->labels();
48         $holidays     = $calendar->labels();
49
50         @dates        = $calendar->search(PATTERN);
51         $dates        = $calendar->search(PATTERN);
52
53         $hashref      = $calendar->tags(YEAR,MONTH,DAY|DATE);
54
55         $days         = $calendar->delta_workdays(YEAR1,MONTH1,DAY1|DATE1
56                                                  ,YEAR2,MONTH2,DAY2|DATE2
57                                                  ,FLAG1,FLAG2);
58
59         ($date,$rest) = $calendar->add_delta_workdays(YEAR,MONTH,DAY|DATE
60                                                      ,DELTA);
61         $date         = $calendar->add_delta_workdays(YEAR,MONTH,DAY|DATE
62                                                      ,DELTA);
63
64         $flag         = $calendar->is_full(YEAR,MONTH,DAY|DATE);
65         $flag         = $calendar->is_half(YEAR,MONTH,DAY|DATE);
66         $flag         = $calendar->is_work(YEAR,MONTH,DAY|DATE);
67

INTERFACE

69       Note that whenever a year number, a date, a time or a combined date and
70       time are expected as input parameters by one of the methods of this
71       class, you can always pass a Date::Pcalc[::Object] date object or an
72       array reference (of an array of appropriate length) instead!
73
74       See Date::Pcalc::Object(3) for more details.
75
76       So instead of calling a given method like this:
77
78         $object->method1( $year,$month,$day );
79         $object->method2( $year1,$month1,$day1, $year2,$month2,$day2 );
80         $object->method3( $year1, $year2, $year3 );
81
82       You can also call it like so:
83
84         $object->method1( $date );
85         $object->method1( [1964,1,3] );
86
87         $object->method2( $year1,$month1,$day1, $date2 );
88         $object->method2( $date1, $year2,$month2,$day2 );
89         $object->method2( $date1, $date2 );
90         $object->method2( $year1,$month1,$day1, [2001,3,17] );
91         $object->method2( [1964,1,3], $year2,$month2,$day2 );
92         $object->method2( [1964,1,3], [2001,3,17] );
93         $object->method2( $date1, [2001,3,17] );
94         $object->method2( [1964,1,3], $date2 );
95
96         $object->method3( $year1, $date2, [2001,3,17] );
97
98       And similarly if a time or a combined date and time are expected.
99
100       If you substitute an expected year number by an anonymous array (this
101       is the recommended way of writing date constants, for increased
102       readability of your programs), it must contain three values,
103       nevertheless (otherwise the use of an anonymous array would be
104       pointless).
105
106       Don't confuse year numbers and their substitutes (a date object or an
107       array reference) with Date::Pcalendar::Year objects, which are a
108       totally different thing!
109
110       But incidentally ":-)", you may also pass a Date::Pcalendar::Year
111       object whenever a year number is expected. However, and perhaps against
112       your expectations at times, especially in conjunction with the method
113       "cache_add()", only the year number from that object will be used, not
114       the year object itself (the year object in question might be using the
115       wrong profile!).
116
117       Moreover, whenever a method of this class returns a date, it does so by
118       returning a Date::Pcalc[::Object] date object.
119

DESCRIPTION

121       • "$calendar = Date::Pcalendar->new(PROFILE[,LANG[,WEEKEND]]);"
122
123         The first argument must be the reference of a hash, which contains a
124         holiday scheme or "profile" to be used in all calculations involving
125         the new calendar object.
126
127         The second argument is optional, and must consist of the valid name
128         or number of a language as provided by the Date::Pcalc(3) module if
129         given.
130
131         After the second argument, a list of day numbers which will
132         constitute the "weekend" can optionally be specified, where 1=Monday,
133         2=Tuesday, 3=Wednesday, 4=Thursday, 5=Friday, 6=Saturday and
134         7=Sunday.
135
136         If no values are given, 6 and 7 (Saturday and Sunday) are
137         automatically taken as default.
138
139         If values outside of the range 1..7 are given, they will be ignored.
140
141         This can be used to switch off this feature and to have no regularly
142         recurring holidays at all when for instance a zero is given.
143
144         See Date::Pcalendar::Profiles(3) and Date::Pcalendar::Year(3) for
145         more details about these arguments and about how to roll your own
146         calendar profiles.
147
148         The method creates a new calendar object for a given profile, i.e., a
149         given location and its scheme of holidays (or a scheme of your own).
150
151         This calendar object is a caching proxy object; it stores the
152         reference of the given profile and contains a hash (the cache) of
153         Date::Pcalendar::Year objects.
154
155       • "$year = $calendar->year(YEAR|DATE);"
156
157         This method returns a Date::Pcalendar::Year object for the given year
158         and the profile that was associated with the given calendar object.
159
160         If the cache in the given calendar object already contains an object
161         for the requested year, the corresponding object reference is simply
162         returned.
163
164         If not, a new Date::Pcalendar::Year object is created using the
165         profile that has been associated with the given calendar object.  The
166         new Date::Pcalendar::Year object is then stored in the calendar
167         object's cache and its object reference is returned.
168
169         A fatal "given year out of range" error will occur if the given year
170         number lies outside the valid range of [1583..2299].
171
172       • "@years = $calendar->cache_keys();"
173
174         This method returns the list of YEAR NUMBERS of the
175         Date::Pcalendar::Year objects contained in the given calendar
176         object's cache.
177
178       • "@years = $calendar->cache_vals();"
179
180         This method returns the list of OBJECT REFERENCES of the
181         Date::Pcalendar::Year objects contained in the given calendar
182         object's cache.
183
184       • "$calendar->cache_clr();"
185
186         This method clears the entire cache of the given calendar object (by
187         destroying the cache hash and creating a new one).
188
189       • "$calendar->cache_add(YEAR|DATE,...);"
190
191         Roughly, this method is a shortcut for
192
193           for $year (@list)
194           {
195               $calendar->year($year);
196           }
197
198       • "$calendar->cache_del(YEAR|DATE,...);"
199
200         This method removes the Date::Pcalendar::Year objects whose year
201         numbers are given from the cache of the given calendar object.
202
203         Year numbers for which the calendar object's cache doesn't contain an
204         entry are simply ignored.
205
206       • "$index = $calendar->date2index(YEAR,MONTH,DAY|DATE);"
207
208         This method converts a given date into the number of the day in that
209         year (this is sometimes also referred to as the "julian" date), i.e.,
210         a number between 0 (for January 1st) and the number of days in the
211         given year minus one, i.e., 364 or 365 (for December 31st).
212
213         You may need this in order to access the bit vectors returned by the
214         Date::Pcalendar::Year methods "vec_full()", "vec_half()" and
215         "vec_work()".
216
217         If the Date::Pcalendar::Year object for the given YEAR is not in the
218         $calendar's cache yet, it will be created and added.
219
220         An exception ("invalid date") is thrown if the given arguments do not
221         constitute a valid date, or ("given year out of range [1583..2299]")
222         if the given year lies outside of the permitted range.
223
224       • "@names = $calendar->labels(YEAR,MONTH,DAY|DATE);"
225
226         "@holidays = $calendar->labels();"
227
228         "$holidays = $calendar->labels();"
229
230         If any arguments are given, they are supposed to represent a date. In
231         that case, a list of all labels (= names of holidays) associated with
232         that date are returned. The first item returned is always the name of
233         the day of week for that date. The corresponding year object for the
234         given date's year is added to the calendar's cache first if
235         necessary.
236
237         If no arguments are given, the list of all available labels in all
238         years that have previously been accessed in the given calendar (i.e.,
239         the years which are already in the given calendar's cache) is
240         constructed. Note that this means that the returned list will be
241         empty if there are no year objects in the given calendar's cache yet
242         (!). The returned list does NOT include any names of the days of week
243         (which would be pointless in this case).
244
245         Multiple labels are reported only once.
246
247         Usually all years have the same set of labels, so it may seem
248         superfluous to scan all the years in the cache instead of just one.
249         But there may be exceptions, because it is possible to define
250         calendar profiles which do not contain all possible holidays in every
251         year. See Date::Pcalendar::Profiles(3) and Date::Pcalendar::Year(3)
252         for more details.
253
254         In list context, the resulting list itself is returned. In scalar
255         context, the number of items in the resulting list is returned.
256
257       • "@dates = $calendar->search(PATTERN);"
258
259         "$dates = $calendar->search(PATTERN);"
260
261         This method searches through all the labels in all years that have
262         previously been accessed in the given calendar (i.e., the years which
263         are already in the given calendar's cache) and returns a list of date
264         objects with all dates whose labels match the given pattern.
265
266         (Use the methods "cache_clr()", "cache_add()" and "cache_del()" in
267         order to put the year numbers you want into the calendar object's
268         cache, or to make sure it only contains the year numbers you want to
269         search.)
270
271         Note that this is a simple, case-insensitive substring search, NOT a
272         full-fledged regular expression search!
273
274         The result is guaranteed to be sorted chronologically.
275
276         In scalar context, only the number of items in the resulting list is
277         returned, instead of the resulting list itself (as in list context).
278
279       • "$hashref = $calendar->tags(YEAR,MONTH,DAY|DATE);"
280
281         This method returns a hash reference for the given calendar and date.
282         The hash it refers to is a copy of the calendar profile's internal
283         hash which contains the names for the given date as keys and 0, 1, 2,
284         or 3 as their corresponding values meaning the following:
285
286             0    =>    commemorative day
287             1    =>    "half" holiday
288             2    =>    "full" holiday
289             3    =>    both a "half" and a "full" holiday
290
291         The value "3" should only occur if a date has been redefined by the
292         underlying profile using the same key (i.e., the same name) but with
293         a different type of holiday.
294
295       • "$days = $calendar->delta_workdays(YEAR1,MONTH1,DAY1,
296         YEAR2,MONTH2,DAY2, FLAG1,FLAG2);"
297
298         "$days = $calendar->delta_workdays(DATE1,DATE2,FLAG1,FLAG2);"
299
300         This method calculates the number of work days (i.e., the number of
301         days, but excluding all holidays) between two dates.
302
303         In other words, this method is equivalent to the "Delta_Days()"
304         function of the Date::Pcalc module, except that it disregards
305         holidays in its counting.
306
307         The two flags indicate whether the start and end dates should be
308         included in the counting (that is, of course, only in case they
309         aren't holidays), or not.
310
311         It is common, for example, that you want to know how many work days
312         are left between the current date and a given deadline.
313
314         Typically, you will want to count the current date but not the
315         deadline's date. So you would specify "true" ("1") for FLAG1 and
316         "false" ("0") for FLAG2 in order to achieve that.
317
318         In other words, a value of "true" means "including this date", a
319         value of "false" means "excluding this date".
320
321         As with the "Delta_Days()" function from the Date::Pcalc module, the
322         dates have to be given in chronological order to yield a positive
323         result. If the dates are reversed, the result will be negative.
324
325         The parameter FLAG1 is associated with the first given date, the
326         parameter FLAG2 with the second given date (regardless of whether the
327         dates are in chronological order or not).
328
329         An exception ("invalid date") is raised if either of the two date
330         arguments does not constitute a valid date.
331
332       • "($date,$rest) = $calendar->add_delta_workdays(YEAR,MONTH,DAY,
333         DELTA);"
334
335         "($date,$rest) = $calendar->add_delta_workdays(DATE,DELTA);"
336
337         "$date = $calendar->add_delta_workdays(YEAR,MONTH,DAY, DELTA);"
338
339         "$date = $calendar->add_delta_workdays(DATE,DELTA);"
340
341         This method is the equivalent of the "Add_Delta_Days()" function from
342         the Date::Pcalc module, except that it adds work days and skips
343         holidays.
344
345         In other words, you can add or subtract a number of work days "DELTA"
346         to/from a given date and get a new date as the result (as a
347         Date::Pcalc object).
348
349         You add days (i.e., you go forward in time) with a positive offset
350         "DELTA", and you subtract days (i.e., you go backwards in time) with
351         a negative offset.
352
353         Note that an exception ("invalid date") is raised if the given date
354         argument does not constitute a valid date.
355
356         In scalar context, the method just returns the resulting date object,
357         whereas in list context the method not only returns the new date, but
358         also a "rest". This rest is useful for cases in which your profile
359         contains "half" holidays, or when you add or subtract fractions of a
360         day.
361
362         Sometimes it is not possible to accomodate the requested number of
363         work days, and a rest remains.
364
365         This rest can currently only assume the value "0.0" (zero), "-0.5"
366         (minus one half) or "0.5" (one half), provided you use only integral
367         or multiples of 0.5 as offsets. A rest of zero indicates that the
368         calculation yielded an exact result. If the rest is 0.5 or -0.5, this
369         is to be interpreted as "the resulting date at 12:00 o'clock",
370         instead of as "the resulting date at 0:00 o'clock".
371
372         The rest is always positive (or zero) if the offset "DELTA" is
373         positive (or zero), and always negative (or zero) if the offset is
374         negative (or zero).
375
376         Example:
377
378           #!perl
379           use Date::Pcalendar;
380           use Date::Pcalendar::Profiles qw( $Profiles );
381           $year = shift;
382           $cal = Date::Pcalendar->new( $Profiles->{'sdm-MUC'} );
383           ($date,$rest) = $cal->add_delta_workdays($year,1,3, -3);
384           $date->date_format(1);
385           print "\$date = $date, \$rest = $rest.\n";
386           __END__
387
388         This program calculates "January 3rd of the given year minus 3 work
389         days":
390
391           > perl test.pl 2001
392           $date = 28-Dec-2000, $rest = 0.
393           > perl test.pl 2002
394           $date = 28-Dec-2001, $rest = -0.5.
395
396         Note that December 31st is a "half" holiday in 2001 for the calendar
397         profile used in this example.
398
399         You can easily verify the results above with the help of the
400         "calendar.cgi" CGI script or the "linearcal.pl" script from the
401         "examples" subdirectory in the Date::Pcalc distribution.
402
403         BEWARE that this method may currently return unexpected (i.e.,
404         contradicting the above documentation) or plain wrong results when
405         going back in time (this is a bug!).
406
407         However, it works correctly and as documented above when going
408         forward in time.
409
410       • "$flag = $calendar->is_full(YEAR,MONTH,DAY|DATE);"
411
412         This method returns "true" ("1") if the bit corresponding to the
413         given date is set in the bit vector representing "full" holidays, and
414         "false" ("0") otherwise.
415
416         I.e., the method returns "true" if the given date is a (full) holiday
417         (according to the calendar profile associated with the given calendar
418         object).
419
420         The corresponding Date::Pcalendar::Year object is created first and
421         stored in the calendar object's cache if necessary (if it's not
422         already there).
423
424         Note that you can get a reference to this bit vector (in order to use
425         this bit vector in bit vector operations) as follows:
426
427           $vec_full = $calendar->year($year)->vec_full();
428
429         The number of bits in this bit vector is the same as the number of
430         days in the given year "$year", which you can retrieve through either
431         ""$days = $vec_full->Size();"" or ""$days = $year->val_days();"".
432
433         See Date::Pcalendar::Year(3) and Bit::Vector(3) for more details.
434
435       • "$flag = $calendar->is_half(YEAR,MONTH,DAY|DATE);"
436
437         This method returns "true" ("1") if the bit corresponding to the
438         given date is set in the bit vector representing "half" holidays, and
439         "false" ("0") otherwise.
440
441         I.e., the method returns "true" if the given date is a half holiday
442         (according to the calendar profile associated with the given calendar
443         object).
444
445         Note that if a date is a "full" holiday, the "half" bit is never set,
446         even if you try to do so in your calendar profile, on purpose or by
447         accident.
448
449         The corresponding Date::Pcalendar::Year object is created first and
450         stored in the calendar object's cache if necessary (if it's not
451         already there).
452
453         Note that you can get a reference to this bit vector (in order to use
454         this bit vector in bit vector operations) as follows:
455
456           $vec_half = $calendar->year($year)->vec_half();
457
458         The number of bits in this bit vector is the same as the number of
459         days in the given year "$year", which you can retrieve through either
460         ""$days = $vec_half->Size();"" or ""$days = $year->val_days();"".
461
462         See Date::Pcalendar::Year(3) and Bit::Vector(3) for more details.
463
464       • "$flag = $calendar->is_work(YEAR,MONTH,DAY|DATE);"
465
466         This method returns "true" ("1") if the bit corresponding to the
467         given date is set in the bit vector used to perform all sorts of
468         calculations, and "false" ("0") otherwise.
469
470         The corresponding Date::Pcalendar::Year object is created first and
471         stored in the calendar object's cache if necessary (if it's not
472         already there).
473
474         BEWARE that the "work" in this method's name does NOT come from "work
475         days"!
476
477         It comes from the fact that the corresponding bit vector can be used
478         for any "work" that you need to do. In other words, it's a "work
479         space".
480
481         Therefore, this bit vector might contain about everything you could
482         imagine - including a bit pattern which marks all "work days" with
483         set bits, if it so happens!
484
485         But you better don't rely on it, unless you put the bit pattern there
486         yourself in the first place.
487
488         Note that you can get a reference to this bit vector (in order to
489         fill it with any bit pattern you like) as follows:
490
491           $vec_work = $calendar->year($year)->vec_work();
492
493         The number of bits in this bit vector is the same as the number of
494         days in the given year "$year", which you can retrieve through either
495         ""$days = $vec_work->Size();"" or ""$days = $year->val_days();"".
496
497         See Date::Pcalendar::Year(3) and Bit::Vector(3) for more details.
498

SEE ALSO

500       Date::Pcalendar::Year(3), Date::Pcalendar::Profiles(3),
501       Date::Pcalc::Object(3), Date::Pcalc(3), Date::Calc::Util(3),
502       Bit::Vector(3).
503

LIMITATIONS

505       The calendar profiles included in Date::Pcalendar::Profiles(3) usually
506       do not take historical irregularities into account (even though some do
507       in order to show how this can be done), they only provide means for
508       calculating regularly recurring events (the profiles should therefore
509       not be relied upon for historical faithfulness).
510

KNOWN BUGS

512       The method "add_delta_workdays()" is known to produce results which are
513       sometimes off by one working day when a negative offset is used. As a
514       workaround, try to add one working day first and then subtract one
515       working day more than initially intended. See also the file
516       "examples/bug.pl" for how to do this.
517

VERSION

519       This man page documents "Date::Pcalendar" version 6.1.
520

AUTHOR

522         Steffen Beyer
523         mailto:STBEY@cpan.org
524         http://www.engelschall.com/u/sb/download/
525
527       Copyright (c) 2000 - 2009 by Steffen Beyer. All rights reserved.
528

LICENSE

530       This package is free software; you can redistribute it and/or modify it
531       under the same terms as Perl itself, i.e., under the terms of the
532       "Artistic License" or the "GNU General Public License".
533
534       Please refer to the files "Artistic.txt" and "GNU_GPL.txt" in this
535       distribution for details!
536

DISCLAIMER

538       This package is distributed in the hope that it will be useful, but
539       WITHOUT ANY WARRANTY; without even the implied warranty of
540       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
541
542       See the "GNU General Public License" for more details.
543
544
545
546perl v5.36.0                      2023-01-20                      Pcalendar(3)
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