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129 | .\" ======================================================================== | |
130 | .\" | |
131 | .IX Title "OBJECT 1" | |
132 | .TH OBJECT 1 "2002-09-28" "perl v5.8.0" "User Contributed Perl Documentation" | |
133 | .SH "NAME" | |
134 | Date::Calc::Object \- Object\-oriented add\-on for Date::Calc with overloaded operators | |
135 | .SH "MOTTO" | |
136 | .IX Header "MOTTO" | |
137 | Make frequent things easy and infrequent or hard things possible | |
138 | .SH "PREFACE" | |
139 | .IX Header "PREFACE" | |
140 | Note that you do \fB\s-1NOT\s0\fR need to "\f(CW\*(C`use Date::Calc qw(...);\*(C'\fR" in | |
141 | addition to this module. | |
142 | .PP | |
143 | Simply | |
144 | .PP | |
145 | .Vb 1 | |
146 | \& use Date::Calc::Object qw(...); | |
147 | .Ve | |
148 | .PP | |
149 | \&\fB\s-1INSTEAD\s0 \s-1OF\s0\fR | |
150 | .PP | |
151 | .Vb 1 | |
152 | \& use Date::Calc qw(...); | |
153 | .Ve | |
154 | .PP | |
155 | with the same "\f(CW\*(C`qw(...)\*(C'\fR\*(L" as you would with the \*(R"Date::Calc\*(L" | |
156 | module, and then forget about \*(R"Date::Calc::Object" altogether. | |
157 | .PP | |
158 | The rest of your existing code doesn't change at all. | |
159 | .PP | |
160 | Note also that in order to create a new date object, you do not | |
161 | need to use | |
162 | .PP | |
163 | .Vb 1 | |
164 | \& $date_object = Date::Calc::Object->new(...); | |
165 | .Ve | |
166 | .PP | |
167 | (but you may), and should use | |
168 | .PP | |
169 | .Vb 1 | |
170 | \& $date_object = Date::Calc->new(...); | |
171 | .Ve | |
172 | .PP | |
173 | instead (saves you some typing and is a trifle faster). | |
174 | .SH "SYNOPSIS" | |
175 | .IX Header "SYNOPSIS" | |
176 | .Sh "Export tags" | |
177 | .IX Subsection "Export tags" | |
178 | .Vb 3 | |
179 | \& :all - all functions from Date::Calc | |
180 | \& :aux - auxiliary functions shift_* | |
181 | \& :ALL - both :all and :aux | |
182 | .Ve | |
183 | .Sh "Functions" | |
184 | .IX Subsection "Functions" | |
185 | See \fIDate::Calc\fR\|(3) for a list of available functions. | |
186 | .PP | |
187 | .Vb 4 | |
188 | \& $year = shift_year(\e@_); | |
189 | \& ($year,$mm,$dd) = shift_date(\e@_); | |
190 | \& ($hrs,$min,$sec) = shift_time(\e@_); | |
191 | \& ($year,$mm,$dd,$hrs,$min,$sec) = shift_datetime(\e@_); | |
192 | .Ve | |
193 | .Sh "Methods" | |
194 | .IX Subsection "Methods" | |
195 | .Vb 5 | |
196 | \& $old = Date::Calc->accurate_mode([FLAG]); | |
197 | \& $old = Date::Calc->number_format([NUMBER|CODEREF]); | |
198 | \& $old = Date::Calc->delta_format([NUMBER|CODEREF]); # global default | |
199 | \& $old = Date::Calc->date_format([NUMBER|CODEREF]); # global default | |
200 | \& $old = Date::Calc->language([LANGUAGE]); # global default | |
201 | .Ve | |
202 | .PP | |
203 | .Vb 5 | |
204 | \& $old = $date->accurate_mode([FLAG]); # is global nevertheless! | |
205 | \& $old = $date->number_format([NUMBER|CODEREF]); # is global nevertheless! | |
206 | \& $old = $date->delta_format([NUMBER|CODEREF]); # individual override | |
207 | \& $old = $date->date_format([NUMBER|CODEREF]); # individual override | |
208 | \& $old = $date->language([LANGUAGE]); # individual override | |
209 | .Ve | |
210 | .PP | |
211 | .Vb 5 | |
212 | \& $flag = $date->is_delta(); | |
213 | \& $flag = $date->is_date(); | |
214 | \& $flag = $date->is_short(); # i.e., has no time part | |
215 | \& $flag = $date->is_long(); # i.e., has time part | |
216 | \& $flag = $date->is_valid(); | |
217 | .Ve | |
218 | .PP | |
219 | .Vb 6 | |
220 | \& $date = Date::Calc->new([TYPE]); | |
221 | \& $date = Date::Calc->new([TYPE,]YEAR,MONTH,DAY[,HRS,MIN,SEC]); | |
222 | \& $date = Date::Calc->new($arrayref); | |
223 | \& $newdate = $somedate->new([TYPE]); | |
224 | \& $newdate = $somedate->new([TYPE,]YEAR,MONTH,DAY[,HRS,MIN,SEC]); | |
225 | \& $newdate = $somedate->new($arrayref); | |
226 | .Ve | |
227 | .PP | |
228 | .Vb 4 | |
229 | \& $datecopy = $date->clone(); | |
230 | \& $targetdate->copy($sourcedate); | |
231 | \& $targetdate->copy($arrayref); | |
232 | \& $targetdate->copy(@list); | |
233 | .Ve | |
234 | .PP | |
235 | .Vb 6 | |
236 | \& ($year,$month,$day) = $date->date([TYPE]); | |
237 | \& ($year,$month,$day) = $date->date([TYPE,]YEAR,MONTH,DAY[,HRS,MIN,SEC]); | |
238 | \& ($year,$month,$day) = $date->date($arrayref); | |
239 | \& ([$hrs,$min,$sec]) = $date->time([TYPE]); | |
240 | \& ($hrs,$min,$sec) = $date->time([TYPE,]HRS,MIN,SEC); | |
241 | \& ([$hrs,$min,$sec]) = $date->time($arrayref); | |
242 | .Ve | |
243 | .PP | |
244 | .Vb 4 | |
245 | \& ($year,$month,$day,$hrs,$min,$sec) = | |
246 | \& $date->datetime([TYPE]); | |
247 | \& ($year,$month,$day,$hrs,$min,$sec) = | |
248 | \& $date->datetime([TYPE,]YEAR,MONTH,DAY[,HRS,MIN,SEC]); | |
249 | .Ve | |
250 | .PP | |
251 | .Vb 7 | |
252 | \& $date = Date::Calc->today([FLAG]); | |
253 | \& $date = Date::Calc->now([FLAG]); # shorthand for --+ | |
254 | \& $date = Date::Calc->today_and_now([FLAG]); # <-----+ | |
255 | \& $date = Date::Calc->gmtime([time]); # UTC/GMT | |
256 | \& $date = Date::Calc->localtime([time]); # local time | |
257 | \& $delta = Date::Calc->tzoffset([time]); | |
258 | \& $date = Date::Calc->time2date([time]); # UTC/GMT | |
259 | .Ve | |
260 | .PP | |
261 | .Vb 7 | |
262 | \& $date->today([FLAG]); # updates the date part only | |
263 | \& $date->now([FLAG]); # updates the time part only | |
264 | \& $date->today_and_now([FLAG]); # updates both date and time | |
265 | \& $date->gmtime([time]); # updates both date and time (UTC/GMT) | |
266 | \& $date->localtime([time]); # updates both date and time (local time) | |
267 | \& $delta->tzoffset([time]); # updates both date and time | |
268 | \& $date->time2date([time]); # updates both date and time (UTC/GMT) | |
269 | .Ve | |
270 | .PP | |
271 | .Vb 2 | |
272 | \& $time = Date::Calc->mktime(); # same as "$time = CORE::time();" | |
273 | \& $time = Date::Calc->date2time(); # same as "$time = CORE::time();" | |
274 | .Ve | |
275 | .PP | |
276 | .Vb 2 | |
277 | \& $time = $date->mktime(); # converts into Unix time (local time) | |
278 | \& $time = $date->date2time(); # converts into Unix time (UTC/GMT) | |
279 | .Ve | |
280 | .PP | |
281 | .Vb 6 | |
282 | \& $year = $date->year([YEAR]); | |
283 | \& $month = $date->month([MONTH]); | |
284 | \& $day = $date->day([DAY]); | |
285 | \& $hours = $date->hours([HRS]); | |
286 | \& $minutes = $date->minutes([MIN]); | |
287 | \& $seconds = $date->seconds([SEC]); | |
288 | .Ve | |
289 | .PP | |
290 | .Vb 2 | |
291 | \& $number = $date->number([NUMBER|CODEREF]); | |
292 | \& $string = $date->string([NUMBER|CODEREF][,LANGUAGE]); | |
293 | .Ve | |
294 | .PP | |
295 | .Vb 1 | |
296 | \& $delta->normalize(); # renormalizes a delta vector | |
297 | .Ve | |
298 | .Sh "Overloaded Operators" | |
299 | .IX Subsection "Overloaded Operators" | |
300 | .Vb 4 | |
301 | \& ##################################################### | |
302 | \& # Scalar operands are always converted into a delta # | |
303 | \& # vector with that many days, i.e., [1,0,0,SCALAR] # | |
304 | \& ##################################################### | |
305 | .Ve | |
306 | .Sh "Comparison Operators:" | |
307 | .IX Subsection "Comparison Operators:" | |
308 | .Vb 6 | |
309 | \& if ($date1 < $date2) { # compares date part only | |
310 | \& if ($date1 <= $date2) { # compares date part only | |
311 | \& if ($date1 > $date2) { # compares date part only | |
312 | \& if ($date1 >= $date2) { # compares date part only | |
313 | \& if ($date1 == $date2) { # compares date part only | |
314 | \& if ($date1 != $date2) { # compares date part only | |
315 | .Ve | |
316 | .PP | |
317 | .Vb 1 | |
318 | \& $comp = $date1 <=> $date2; # compares date part only | |
319 | .Ve | |
320 | .PP | |
321 | .Vb 6 | |
322 | \& if ($date1 lt $date2) { # compares both date and time | |
323 | \& if ($date1 le $date2) { # compares both date and time | |
324 | \& if ($date1 gt $date2) { # compares both date and time | |
325 | \& if ($date1 ge $date2) { # compares both date and time | |
326 | \& if ($date1 eq $date2) { # compares both date and time | |
327 | \& if ($date1 ne $date2) { # compares both date and time | |
328 | .Ve | |
329 | .PP | |
330 | .Vb 1 | |
331 | \& $comp = $date1 cmp $date2; # compares both date and time | |
332 | .Ve | |
333 | .PP | |
334 | Note that you can of course also compare two deltas, | |
335 | but not a date and a delta! | |
336 | .PP | |
337 | .Vb 4 | |
338 | \& ################################################## | |
339 | \& # Default TYPE for array refs in comparisons is: # | |
340 | \& # Same as other operand # | |
341 | \& ################################################## | |
342 | .Ve | |
343 | .PP | |
344 | .Vb 2 | |
345 | \& if ([2000,4,1] == $date) { | |
346 | \& if ($today > [2000,4,1]) { | |
347 | .Ve | |
348 | .PP | |
349 | .Vb 1 | |
350 | \& if ($now ge [2000,3,26,2,0,0]) { | |
351 | .Ve | |
352 | .PP | |
353 | .Vb 2 | |
354 | \& if ($delta == [18,0,0]) { | |
355 | \& if ($delta == -1) { | |
356 | .Ve | |
357 | .Sh "Plus:" | |
358 | .IX Subsection "Plus:" | |
359 | .Vb 5 | |
360 | \& $date2 = $date1 + $delta; | |
361 | \& $date2 = $delta + $date1; | |
362 | \& $date += $delta; | |
363 | \& $this = $date++; | |
364 | \& $next = ++$date; | |
365 | .Ve | |
366 | .PP | |
367 | .Vb 5 | |
368 | \& $delta3 = $delta1 + $delta2; | |
369 | \& $delta1 += $delta2; | |
370 | \& $delta += $date; # beware of implicit type change! | |
371 | \& $delta++; | |
372 | \& ++$delta; | |
373 | .Ve | |
374 | .PP | |
375 | .Vb 4 | |
376 | \& ##################################################### | |
377 | \& # Default TYPE for array refs in '+' operations is: # | |
378 | \& # Opposite of other operand # | |
379 | \& ##################################################### | |
380 | .Ve | |
381 | .PP | |
382 | .Vb 6 | |
383 | \& $date2 = [2000,3,26] + $delta; | |
384 | \& $date2 = $date1 + [+1,0,0]; | |
385 | \& $date2 = [0,0,-1] + $date1; | |
386 | \& $date2 = $date1 + 1; | |
387 | \& $date += [0,0,+1]; | |
388 | \& $date += 2; | |
389 | .Ve | |
390 | .PP | |
391 | .Vb 6 | |
392 | \& $delta3 = [1,+1,0,-1] + $delta2; | |
393 | \& $delta3 = $delta1 + [1,0,0,+1]; | |
394 | \& $delta3 = $delta1 + 1; | |
395 | \& $delta += [1,0,+1,0]; | |
396 | \& $delta += [2000,3,26]; # beware of implicit type change! | |
397 | \& $delta += 7; | |
398 | .Ve | |
399 | .Sh "Unary Minus:" | |
400 | .IX Subsection "Unary Minus:" | |
401 | .Vb 1 | |
402 | \& $delta2 = -$delta1; | |
403 | .Ve | |
404 | .Sh "Minus:" | |
405 | .IX Subsection "Minus:" | |
406 | .Vb 6 | |
407 | \& $delta = $date2 - $date1; | |
408 | \& $date2 = $date1 - $delta; | |
409 | \& $date -= $delta; | |
410 | \& $date2 -= $date1; # beware of implicit type change! | |
411 | \& $this = $date--; | |
412 | \& $prev = --$date; | |
413 | .Ve | |
414 | .PP | |
415 | .Vb 4 | |
416 | \& $delta3 = $delta2 - $delta1; | |
417 | \& $delta2 -= $delta1; | |
418 | \& $delta--; | |
419 | \& --$delta; | |
420 | .Ve | |
421 | .PP | |
422 | .Vb 4 | |
423 | \& ##################################################### | |
424 | \& # Default TYPE for array refs in '-' operations is: # | |
425 | \& # Always a date # | |
426 | \& ##################################################### | |
427 | .Ve | |
428 | .PP | |
429 | .Vb 8 | |
430 | \& $delta = $today - [2000,3,26]; | |
431 | \& $delta = [2000,4,1] - $date; | |
432 | \& $date2 = [2000,3,26] - $delta; | |
433 | \& $date2 = $date1 - [1,0,0,+7]; | |
434 | \& $date2 = $date1 - 7; | |
435 | \& $date -= [1,0,0,+1]; # better add [0,0,-1] instead! | |
436 | \& $date2 -= [2000,3,26]; # beware of implicit type change! | |
437 | \& $date2 -= 1; | |
438 | .Ve | |
439 | .PP | |
440 | .Vb 4 | |
441 | \& $delta3 = [1,0,+1,0] - $delta1; | |
442 | \& $delta3 = $delta2 - [1,0,0,-1]; | |
443 | \& $delta -= [1,0,0,+1]; | |
444 | \& $delta -= 7; | |
445 | .Ve | |
446 | .Sh "Miscellaneous Operators:" | |
447 | .IX Subsection "Miscellaneous Operators:" | |
448 | .Vb 2 | |
449 | \& $string = "$date"; | |
450 | \& $string = "$delta"; | |
451 | .Ve | |
452 | .PP | |
453 | .Vb 2 | |
454 | \& print "$date\en"; | |
455 | \& print "$delta\en"; | |
456 | .Ve | |
457 | .PP | |
458 | .Vb 2 | |
459 | \& if ($date) { # date is valid | |
460 | \& if ($delta) { # delta is valid | |
461 | .Ve | |
462 | .PP | |
463 | .Vb 2 | |
464 | \& $days = abs($date); | |
465 | \& $diff = abs($delta); # can be negative! | |
466 | .Ve | |
467 | .PP | |
468 | .Vb 1 | |
469 | \& $diff = abs(abs($delta)); # always positive | |
470 | .Ve | |
471 | .SH "DESCRIPTION" | |
472 | .IX Header "DESCRIPTION" | |
473 | .IP "\(bu" 2 | |
474 | \&\s-1FLAG\s0 | |
475 | .Sp | |
476 | \&\*(L"\s-1FLAG\s0\*(R" is either 0 (for \*(L"false\*(R") or 1 (for \*(L"true\*(R"). | |
477 | .Sp | |
478 | In the case of "\f(CW\*(C`accurate_mode()\*(C'\fR\*(L", this switches \*(R"accurate mode" | |
479 | on and off (see further below for an explanation of what that is). | |
480 | .Sp | |
481 | In the case of "\f(CW\*(C`today()\*(C'\fR\*(L", \*(R"\f(CW\*(C`now()\*(C'\fR\*(L" and \*(R"\f(CW\*(C`today_and_now()\*(C'\fR\*(L", | |
482 | a \*(R"true\*(L" value indicates \*(R"\s-1GMT\s0" (Greenwich Mean Time), as opposed | |
483 | to local time, which is the default. | |
484 | .IP "\(bu" 2 | |
485 | \&\s-1NUMBER\s0 | |
486 | .Sp | |
487 | \&\*(L"\s-1NUMBER\s0\*(R" is a number between 0 and 2 (for \*(L"\fInumber_format()\fR\*(R" and \*(L"\fInumber()\fR\*(R") | |
488 | or between 0 and 3 (for \*(L"\fIdelta_format()\fR\*(R", \*(L"\fIdate_format()\fR\*(R" and \*(L"\fIstring()\fR\*(R"), | |
489 | indicating which of the three/four predefined formats, respectively, | |
490 | should be used for converting a date into numeric representation | |
491 | (needed for comparing dates, for instance) or string representation. | |
492 | .Sp | |
493 | Format #0 is the default at startup and the simplest of all (and | |
494 | should be fastest to calculate, too). | |
495 | .Sp | |
496 | The string representation of dates in format #0 also has the advantage of | |
497 | being sortable in chronological order (and of complying with \s-1ISO\s0\ 8601). | |
498 | .Sp | |
499 | (The numeric formats are (trivially) always sortable in chronological | |
500 | order of course.) | |
501 | .Sp | |
502 | The other formats are increasingly more sophisticated (in terms of | |
503 | esthetics and computation time) with increasing number: | |
504 | .Sp | |
505 | .Vb 1 | |
506 | \& Delta number formats (short): | |
507 | .Ve | |
508 | .Sp | |
509 | .Vb 3 | |
510 | \& 0 13603 | |
511 | \& 1 13603 | |
512 | \& 2 13603 | |
513 | .Ve | |
514 | .Sp | |
515 | .Vb 1 | |
516 | \& Delta string formats (short): | |
517 | .Ve | |
518 | .Sp | |
519 | .Vb 4 | |
520 | \& 0 '+0+0+13603' | |
521 | \& 1 '+0 +0 +13603' | |
522 | \& 2 '+0Y +0M +13603D' | |
523 | \& 3 '+0 Y +0 M +13603 D' | |
524 | .Ve | |
525 | .Sp | |
526 | .Vb 1 | |
527 | \& Date number formats (short): | |
528 | .Ve | |
529 | .Sp | |
530 | .Vb 3 | |
531 | \& 0 20010401 | |
532 | \& 1 730576 | |
533 | \& 2 730576 | |
534 | .Ve | |
535 | .Sp | |
536 | .Vb 1 | |
537 | \& Date string formats (short): | |
538 | .Ve | |
539 | .Sp | |
540 | .Vb 4 | |
541 | \& 0 '20010401' | |
542 | \& 1 '01-Apr-2001' | |
543 | \& 2 'Sun 1-Apr-2001' | |
544 | \& 3 'Sunday, April 1st 2001' | |
545 | .Ve | |
546 | .Sp | |
547 | .Vb 1 | |
548 | \& Delta number formats (long): | |
549 | .Ve | |
550 | .Sp | |
551 | .Vb 3 | |
552 | \& 0 13603.012959 | |
553 | \& 1 13603.012959 | |
554 | \& 2 13603.0624884259 | |
555 | .Ve | |
556 | .Sp | |
557 | .Vb 1 | |
558 | \& Delta string formats (long): | |
559 | .Ve | |
560 | .Sp | |
561 | .Vb 4 | |
562 | \& 0 '+0+0+13603+1+29+59' | |
563 | \& 1 '+0 +0 +13603 +1 +29 +59' | |
564 | \& 2 '+0Y +0M +13603D +1h +29m +59s' | |
565 | \& 3 '+0 Y +0 M +13603 D +1 h +29 m +59 s' | |
566 | .Ve | |
567 | .Sp | |
568 | .Vb 1 | |
569 | \& Date number formats (long): | |
570 | .Ve | |
571 | .Sp | |
572 | .Vb 3 | |
573 | \& 0 20010401.082959 | |
574 | \& 1 730576.082959 | |
575 | \& 2 730576.354155093 | |
576 | .Ve | |
577 | .Sp | |
578 | .Vb 1 | |
579 | \& Date string formats (long): | |
580 | .Ve | |
581 | .Sp | |
582 | .Vb 4 | |
583 | \& 0 '20010401082959' | |
584 | \& 1 '01-Apr-2001 08:29:59' | |
585 | \& 2 'Sun 1-Apr-2001 08:29:59' | |
586 | \& 3 'Sunday, April 1st 2001 08:29:59' | |
587 | .Ve | |
588 | .Sp | |
589 | If a number outside of the permitted range is specified, or if the value | |
590 | is not a code reference (see also the next section below for more details), | |
591 | the default format #0 is used instead. | |
592 | .IP "\(bu" 2 | |
593 | \&\s-1CODEREF\s0 | |
594 | .Sp | |
595 | \&\*(L"\s-1CODEREF\s0\*(R" is the reference of a subroutine which can be passed to the | |
596 | methods \*(L"\fInumber_format()\fR\*(R", \*(L"\fIdelta_format()\fR\*(R" and \*(L"\fIdate_format()\fR\*(R" in order | |
597 | to install a callback function which will be called subsequently whenever | |
598 | a date (or delta) object needs to be (implicitly) converted into a number | |
599 | or string. | |
600 | .Sp | |
601 | This happens for instance when you compare two date objects, or when you | |
602 | put a date object reference in a string between double quotes. | |
603 | .Sp | |
604 | Such a \*(L"\s-1CODEREF\s0\*(R" can also be passed to the methods \*(L"\fInumber()\fR\*(R" and | |
605 | \&\*(L"\fIstring()\fR\*(R" for explicitly converting a date object as desired. | |
606 | .IP "\(bu" 2 | |
607 | \&\s-1LANGUAGE\s0 | |
608 | .Sp | |
609 | \&\*(L"\s-1LANGUAGE\s0\*(R" is either a number in the range \f(CW\*(C`[1..Languages()]\*(C'\fR, | |
610 | or one of the strings "\f(CW\*(C`Language_to_Text(1..Languages())\*(C'\fR" | |
611 | (see also \fIDate::Calc\fR\|(3)). | |
612 | .IP "\(bu" 2 | |
613 | \&\s-1TYPE\s0 | |
614 | .Sp | |
615 | \&\*(L"\s-1TYPE\s0\*(R" is 0 for a regular date and 1 for a delta vector (a list of | |
616 | year, month, day and optionally hours, minutes and seconds offsets). | |
617 | .IP "\(bu" 2 | |
618 | Storage | |
619 | .Sp | |
620 | \&\*(L"Date::Calc\*(R" objects are implemented as two nested arrays. | |
621 | .Sp | |
622 | The \*(L"blessed\*(R" array (whose reference is the object reference | |
623 | you receive when calling the \*(L"\fInew()\fR\*(R" method) contains an | |
624 | anonymous array at position zero and the object's data in | |
625 | its remaining fields. | |
626 | .Sp | |
627 | The embedded anonymous array is used for storing the object's | |
628 | attributes (flags). | |
629 | .Sp | |
630 | Dates and delta vectors always comprise either 3 or 6 data values: | |
631 | Year, month, day plus (optionally) hours, minutes and seconds. | |
632 | .Sp | |
633 | These values are stored in the \*(L"blessed\*(R" array at positions 1..3 | |
634 | or 1..6, respectively. | |
635 | .Sp | |
636 | An object without the time values is therefore called \*(L"short\*(R", | |
637 | and an object having time values is called \*(L"long\*(R" throughout | |
638 | this manual. | |
639 | .Sp | |
640 | Hint: Whenever possible, if you do not need the time values, omit | |
641 | them, i.e., always use the \*(L"short\*(R" form of the object if possible, | |
642 | this will speed up calculations a little (the short form uses | |
643 | different (faster) functions for all calculations internally). | |
644 | .Sp | |
645 | The embedded anonymous array contains various flags: | |
646 | .Sp | |
647 | At position zero, it contains the \*(L"\s-1TYPE\s0\*(R" indicator which determines | |
648 | whether the object is a date or a delta vector. | |
649 | .Sp | |
650 | At position 1, the object stores the \*(L"\s-1NUMBER\s0\*(R" of one of the delta | |
651 | vector formats, or the reference of a callback function which converts | |
652 | the contents of the object into string representation if it's a delta | |
653 | vector, or \*(L"undef\*(R" if the global settings apply. | |
654 | .Sp | |
655 | At position 2, the object stores the \*(L"\s-1NUMBER\s0\*(R" of one of the date formats, | |
656 | or the reference of a callback function which converts the contents of | |
657 | the object into string representation if it's a date, or \*(L"undef\*(R" if the | |
658 | global settings apply. | |
659 | .Sp | |
660 | At position 3, the object stores the \*(L"\s-1LANGUAGE\s0\*(R" to be used for all | |
661 | conversions into strings (where applicable), or \*(L"undef\*(R" if the global | |
662 | language setting applies. | |
663 | .Sp | |
664 | Note that your callback functions (see the section \*(L"Callback Functions\*(R" | |
665 | further below for more details) do not need to pay attention to the | |
666 | value at position 3, the language (of the \*(L"Date::Calc\*(R" module) | |
667 | will automatically be set to this value whenever the callback | |
668 | functions are called, and automatically reset to its former value | |
669 | after the callback. | |
670 | .Sp | |
671 | So if your callback functions use the \*(L"*_to_Text*\*(R" functions from | |
672 | the \*(L"Date::Calc\*(R" module, they will automatically use the correct | |
673 | language. | |
674 | .Sp | |
675 | Be reminded though that you should \fB\s-1NEVER\s0\fR access the object's | |
676 | internal data directly, i.e., through their positional numbers, | |
677 | but \fB\s-1ALWAYS\s0\fR through their respective accessor methods, e.g.: | |
678 | .Sp | |
679 | .Vb 16 | |
680 | \& year() | |
681 | \& month() | |
682 | \& day() | |
683 | \& hours() | |
684 | \& minutes() | |
685 | \& seconds() | |
686 | \& date() | |
687 | \& time() | |
688 | \& datetime() | |
689 | \& is_delta() | |
690 | \& is_date() | |
691 | \& is_short() | |
692 | \& is_long() | |
693 | \& delta_format() | |
694 | \& date_format() | |
695 | \& language() | |
696 | .Ve | |
697 | .Sp | |
698 | And although position 4 and onward in the embedded anonymous array is | |
699 | currently unused, it might not stay so in future releases of this module. | |
700 | .Sp | |
701 | Therefore, in case you need more attributes in a subclass of the | |
702 | \&\*(L"Date::Calc[::Object]\*(R" class, I suggest using values starting at | |
703 | positions a bit further up, e.g. 6, 8 or 10. | |
704 | .IP "\(bu" 2 | |
705 | Invalid Dates | |
706 | .Sp | |
707 | Only \*(L"\fInew()\fR\*(R" allows to create objects containing possibly invalid | |
708 | dates (needed for reading in and evaluating user input, for example). | |
709 | .IP "\(bu" 2 | |
710 | Usage | |
711 | .Sp | |
712 | The methods | |
713 | .Sp | |
714 | .Vb 14 | |
715 | \& accurate_mode() | |
716 | \& number_format() | |
717 | \& delta_format() | |
718 | \& date_format() | |
719 | \& language() | |
720 | \& date() | |
721 | \& time() | |
722 | \& datetime() | |
723 | \& year() | |
724 | \& month() | |
725 | \& day() | |
726 | \& hours() | |
727 | \& minutes() | |
728 | \& seconds() | |
729 | .Ve | |
730 | .Sp | |
731 | are used for reading as well as for setting attributes. They simply | |
732 | return the values in question if they are called without parameters. | |
733 | .Sp | |
734 | The methods | |
735 | .Sp | |
736 | .Vb 5 | |
737 | \& accurate_mode() | |
738 | \& number_format() | |
739 | \& delta_format() | |
740 | \& date_format() | |
741 | \& language() | |
742 | .Ve | |
743 | .Sp | |
744 | always return the previous value if a new value is set. This allows | |
745 | you to change these values temporarily and to restore their old value | |
746 | afterwards more easily (but you can also override the \*(L"format\*(R" and | |
747 | \&\*(L"language\*(R" settings directly when calling the \*(L"\fInumber()\fR\*(R" or \*(L"\fIstring()\fR\*(R" | |
748 | method). | |
749 | .Sp | |
750 | The methods | |
751 | .Sp | |
752 | .Vb 9 | |
753 | \& date() | |
754 | \& time() | |
755 | \& datetime() | |
756 | \& year() | |
757 | \& month() | |
758 | \& day() | |
759 | \& hours() | |
760 | \& minutes() | |
761 | \& seconds() | |
762 | .Ve | |
763 | .Sp | |
764 | always return the new values when the corresponding values have | |
765 | been changed. | |
766 | .Sp | |
767 | The method \*(L"\fIdate()\fR\*(R" \s-1NEVER\s0 returns the time values (hours, minutes, | |
768 | seconds) even if they have just been set using this method (which | |
769 | the method optionally allows). Otherwise it would be very hard to | |
770 | predict the exact number of values it returns, which might lead | |
771 | to errors (wrong number of parameters) elsewhere in your program. | |
772 | .Sp | |
773 | The method \*(L"\fIdatetime()\fR\*(R" \s-1ALWAYS\s0 returns the time values (hours, | |
774 | minutes, seconds) even if the object in question lacks a time | |
775 | part. In that case, zeros are returned for hours, minutes and | |
776 | seconds instead (but the stored time part is left unchanged, | |
777 | whether it exists or not). | |
778 | .Sp | |
779 | If you do not provide values for hours, minutes and seconds when | |
780 | using the method \*(L"\fIdate()\fR\*(R" to set the values for year, month and | |
781 | day, the time part will not be changed (whether it exists or not). | |
782 | .Sp | |
783 | If you do not provide values for hours, minutes and seconds when | |
784 | using the method \*(L"\fIdatetime()\fR\*(R" to set the values for year, month | |
785 | and day, the time part will be filled with zeros (the time part | |
786 | will be created if necessary). | |
787 | .Sp | |
788 | If the object is short, i.e., if it does not have any time values, | |
789 | the method \*(L"\fItime()\fR\*(R" returns an empty list. | |
790 | .Sp | |
791 | If the object is short and the methods \*(L"\fIhours()\fR\*(R", \*(L"\fIminutes()\fR\*(R" or | |
792 | \&\*(L"\fIseconds()\fR\*(R" are used to set any of these time values, the object | |
793 | is automatically promoted to the \*(L"long\*(R" form, and the other two | |
794 | time values are filled with zeros. | |
795 | .Sp | |
796 | The following methods can also return \*(L"undef\*(R" under certain | |
797 | circumstances: | |
798 | .Sp | |
799 | .Vb 13 | |
800 | \& delta_format() | |
801 | \& date_format() | |
802 | \& language() | |
803 | \& is_delta() | |
804 | \& is_date() | |
805 | \& is_short() | |
806 | \& is_long() | |
807 | \& is_valid() | |
808 | \& hours() | |
809 | \& minutes() | |
810 | \& seconds() | |
811 | \& number() | |
812 | \& string() | |
813 | .Ve | |
814 | .Sp | |
815 | The methods \*(L"\fIdelta_format()\fR\*(R", \*(L"\fIdate_format()\fR\*(R" and \*(L"\fIlanguage()\fR\*(R" | |
816 | return \*(L"undef\*(R" when they are called as object methods and no | |
817 | individual override has been defined for the object in question. | |
818 | .Sp | |
819 | The \*(L"is_*()\*(R" predicate methods return \*(L"undef\*(R" if the object in | |
820 | question does not have the expected internal structure. This can | |
821 | happen for instance when you create an empty object with \*(L"\fInew()\fR\*(R". | |
822 | .Sp | |
823 | When called without parameters, the methods \*(L"\fIhours()\fR\*(R", \*(L"\fIminutes()\fR\*(R" | |
824 | and \*(L"\fIseconds()\fR\*(R" return \*(L"undef\*(R" if the object in question does not | |
825 | have a time part. | |
826 | .Sp | |
827 | The methods \*(L"\fInumber()\fR\*(R" and \*(L"\fIstring()\fR\*(R" return \*(L"undef\*(R" if the object | |
828 | in question is not valid (i.e., if \*(L"\fIis_valid()\fR\*(R" returns \*(L"undef\*(R" or | |
829 | false). | |
830 | .Sp | |
831 | And finally, the methods | |
832 | .Sp | |
833 | .Vb 9 | |
834 | \& copy() | |
835 | \& today() | |
836 | \& now() | |
837 | \& today_and_now() | |
838 | \& gmtime() | |
839 | \& localtime() | |
840 | \& tzoffset() | |
841 | \& time2date() | |
842 | \& normalize() | |
843 | .Ve | |
844 | .Sp | |
845 | return the object reference of the (target) object in question | |
846 | for convenience. | |
847 | .IP "\(bu" 2 | |
848 | Import/Export | |
849 | .Sp | |
850 | Note that you can import and export Unix \*(L"time\*(R" values using the | |
851 | methods \*(L"\fIgmtime()\fR\*(R", \*(L"\fIlocaltime()\fR\*(R", \*(L"\fImktime()\fR\*(R", \*(L"\fIdate2time()\fR\*(R" and | |
852 | \&\*(L"\fItime2date()\fR\*(R", both as local time or as \s-1UTC/GMT\s0. | |
853 | .IP "\(bu" 2 | |
854 | Accurate Mode | |
855 | .Sp | |
856 | The method \*(L"\fIaccurate_mode()\fR\*(R" controls the internal flag which | |
857 | determines which of two modes of operation is used. | |
858 | .Sp | |
859 | When set to true (the default at startup), delta vectors are | |
860 | calculated to give the exact difference in days between two | |
861 | dates. The \*(L"year\*(R" and \*(L"month\*(R" entries in the resulting delta | |
862 | vector are always zero in that case. | |
863 | .Sp | |
864 | If \*(L"accurate mode\*(R" is switched off (when the corresponding | |
865 | flag is set to false), delta vectors are calculated with | |
866 | year and month differences. | |
867 | .Sp | |
868 | E.g., the difference between \f(CW\*(C`[1999,12,6]\*(C'\fR and \f(CW\*(C`[2000,6,24]\*(C'\fR | |
869 | is \f(CW\*(C`[+0 +0 +201]\*(C'\fR (plus 201 days) in accurate mode and | |
870 | \&\f(CW\*(C`[+1 \-6 +18]\*(C'\fR (plus one year, minus 6 months, plus 18 days) | |
871 | when accurate mode is switched off. | |
872 | .Sp | |
873 | (The delta vector is calculated by simply taking the difference | |
874 | in years, the difference in months and the difference in days.) | |
875 | .Sp | |
876 | Because years and months have varying lengths in terms of days, | |
877 | the latter is less accurate than the former because it depends | |
878 | on the context of the two dates of which it represents the | |
879 | difference. Added to a different date, the latter delta vector | |
880 | may yield a different offset in terms of days. | |
881 | .Sp | |
882 | Beware also that \- for the same reason \- the absolute value | |
883 | ("\f(CW\*(C`abs()\*(C'\fR\*(L") of a delta vector returns a fictitious number | |
884 | of days if the delta vector contains non-zero values for | |
885 | \&\*(R"year\*(L" and/or \*(R"month" (see also next section below for | |
886 | more details). | |
887 | .Sp | |
888 | Example: | |
889 | .Sp | |
890 | The difference between \f(CW\*(C`[2000,1,1]\*(C'\fR and \f(CW\*(C`[2000,3,1]\*(C'\fR is | |
891 | \&\f(CW\*(C`[+0 +0 +60]\*(C'\fR in accurate mode and \f(CW\*(C`[+0 +2 +0]\*(C'\fR else (one | |
892 | could also call this \*(L"year\-month\-day mode\*(R" or \*(L"\s-1YMD\s0 mode\*(R" for | |
893 | short). | |
894 | .Sp | |
895 | When added to the date \f(CW\*(C`[2000,4,1]\*(C'\fR, the \*(L"accurate\*(R" delta | |
896 | vector yields the date \f(CW\*(C`[2000,5,31]\*(C'\fR, whereas the other delta | |
897 | vector yields the date \f(CW\*(C`[2000,6,1]\*(C'\fR. | |
898 | .Sp | |
899 | Moreover, when added to the date \f(CW\*(C`[1999,1,1]\*(C'\fR, the \*(L"accurate\*(R" | |
900 | delta vector yields the date \f(CW\*(C`[1999,3,2]\*(C'\fR, whereas the \*(L"inaccurate\*(R" | |
901 | delta vector yields the date \f(CW\*(C`[1999,3,1]\*(C'\fR. | |
902 | .Sp | |
903 | Depending on what you want, the one or the other mode may suit | |
904 | you better. | |
905 | .IP "\(bu" 2 | |
906 | Absolute Value | |
907 | .Sp | |
908 | Note that "\f(CW\*(C`abs($date)\*(C'\fR\*(L" and \*(R"\f(CW\*(C`abs($delta)\*(C'\fR\*(L" are just shorthands | |
909 | for \*(R"\f(CW\*(C`$date\->number()\*(C'\fR\*(L" and \*(R"\f(CW\*(C`$delta\->number()\*(C'\fR". | |
910 | .Sp | |
911 | The operator "\f(CW\*(C`abs()\*(C'\fR", when applied to a date or delta vector, | |
912 | returns the corresponding number of days (see below for an exception | |
913 | to this), with the time part (if available) represented by a fraction | |
914 | after the decimal point. | |
915 | .Sp | |
916 | In the case of dates, the absolute value (to the left of the | |
917 | decimal point) is the number of days since the 1st of January | |
918 | 1\ A.D. (by extrapolating the Gregorian calendar back beyond | |
919 | its \*(L"natural\*(R" limit of 1582 A.D.) \fB\s-1PLUS\s0 \s-1ONE\s0\fR. | |
920 | .Sp | |
921 | (I.e., the absolute value of the 1st of January 1 A.D. is 1.) | |
922 | .Sp | |
923 | Exception: | |
924 | .Sp | |
925 | If the \*(L"\s-1NUMBER\s0\*(R" or \*(L"\fInumber_format()\fR\*(R" is set to 0 (the default | |
926 | setting), the absolute value of a date to the left of the decimal | |
927 | point is \*(L"yyyymmdd\*(R", i.e., the number in which the uppermost four | |
928 | digits correspond to the year, the next lower two digits to the | |
929 | month and the lowermost two digits to the day. | |
930 | .Sp | |
931 | In the case of delta vectors, the absolute value (to the left | |
932 | of the decimal point) is simply the difference in days (but | |
933 | see also below). | |
934 | .Sp | |
935 | Note that the absolute value of a delta vector can be negative! | |
936 | .Sp | |
937 | If you want a positive value in all cases, apply the "\f(CW\*(C`abs()\*(C'\fR\*(L" | |
938 | operator again, i.e., \*(R"\f(CW\*(C`$posdiff = abs(abs($delta));\*(C'\fR". | |
939 | .Sp | |
940 | If the delta vector contains non-zero values for \*(L"year\*(R" and/or | |
941 | \&\*(L"month\*(R" (see also the discussion of \*(L"Accurate Mode\*(R" in the section | |
942 | above), an exact representation in days cannot be calculated, | |
943 | because years and months do not have fixed equivalents in days. | |
944 | .Sp | |
945 | If nevertheless you attempt to calculate the absolute value of | |
946 | such a delta vector, a fictitious value is returned, which is | |
947 | calculated by simply multiplying the year difference with 12, | |
948 | adding the month difference, multiplying this sum with 31 and | |
949 | finally adding the day difference. | |
950 | .Sp | |
951 | Beware that because of this, the absolute values of delta | |
952 | vectors are not necessarily contiguous. | |
953 | .Sp | |
954 | Moreover, since there is more than one way to express the | |
955 | difference between two dates, comparisons of delta vectors | |
956 | may not always yield the expected result. | |
957 | .Sp | |
958 | Example: | |
959 | .Sp | |
960 | The difference between the two dates \f(CW\*(C`[2000,4,30]\*(C'\fR and | |
961 | \&\f(CW\*(C`[2001,5,1]\*(C'\fR can be expressed as \f(CW\*(C`[+1 +1 \-29]\*(C'\fR, or as | |
962 | \&\f(CW\*(C`[+1 +0 +1]\*(C'\fR. | |
963 | .Sp | |
964 | The first delta vector has an absolute value of 374, | |
965 | whereas the latter delta vector has an absolute value | |
966 | of only 373 (while the true difference in days between | |
967 | the two dates is 366). | |
968 | .Sp | |
969 | If the date or delta vector has a time part, the time is returned | |
970 | as a fraction of a full day after the decimal point as follows: | |
971 | .Sp | |
972 | If the \*(L"\s-1NUMBER\s0\*(R" or \*(L"\fInumber_format()\fR\*(R" is set to 0 (the default | |
973 | setting) or 1, this fraction is simply \*(L".hhmmss\*(R", i.e., the | |
974 | two digits after the decimal point represent the hours, the | |
975 | next two digits the minutes and the last two digits the seconds. | |
976 | .Sp | |
977 | Note that you cannot simply add and subtract these values to | |
978 | yield meaningful dates or deltas again, you can only use them | |
979 | for comparisons (equal, not equal, less than, greater than, | |
980 | etc.). If you want to add/subtract, read on: | |
981 | .Sp | |
982 | Only when the \*(L"\s-1NUMBER\s0\*(R" or \*(L"\fInumber_format()\fR\*(R" is set to 2, this | |
983 | fraction will be the equivalent number of seconds (i.e., | |
984 | \&\f(CW\*(C`(((hours * 60) + minutes) * 60) + seconds\*(C'\fR) divided by the | |
985 | number of seconds in a full day (i.e., \f(CW\*(C`24*60*60 = 86400\*(C'\fR), | |
986 | or \f(CW\*(C`0/86400\*(C'\fR, \f(CW\*(C`1/86400\*(C'\fR, ... , \f(CW\*(C`86399/86400\*(C'\fR. | |
987 | .Sp | |
988 | In other words, the (mathematically correct) fraction of a day. | |
989 | .Sp | |
990 | You can safely perform arithmetics with these values as far | |
991 | as the internal precision of your vendor's implementation | |
992 | of the C run-time library (on which Perl depends) will permit. | |
993 | .IP "\(bu" 2 | |
994 | Renormalizing Delta Vectors | |
995 | .Sp | |
996 | When adding or subtracting delta vectors to/from one another, | |
997 | the addition or subtraction takes place component by component. | |
998 | .Sp | |
999 | Example: | |
1000 | .Sp | |
1001 | .Vb 2 | |
1002 | \& [+0 +0 +0 +3 +29 +50] + [+0 +0 +0 +0 +55 +5] = [+0 +0 +0 +3 +84 +55] | |
1003 | \& [+0 +0 +0 +3 +29 +50] - [+0 +0 +0 +0 +55 +5] = [+0 +0 +0 +3 -26 +45] | |
1004 | .Ve | |
1005 | .Sp | |
1006 | This may result in time values outside the usual ranges (\f(CW\*(C`[\-23..+23]\*(C'\fR | |
1007 | for hours and \f(CW\*(C`[\-59..+59]\*(C'\fR for minutes and seconds). | |
1008 | .Sp | |
1009 | Note that even though the delta value for days will often become quite large, | |
1010 | it is impossible to renormalize this value because there is no constant | |
1011 | conversion factor from days to months (should it be 28, 29, 30 or 31?). | |
1012 | .Sp | |
1013 | If accurate mode (see further above for what that is) is switched off, | |
1014 | delta vectors can also contain non-zero values for years and months. If | |
1015 | you add or subtract these, the value for months can lie outside the | |
1016 | range \f(CW\*(C`[\-11..11]\*(C'\fR, which isn't wrong, but may seem funny. | |
1017 | .Sp | |
1018 | Therefore, the \*(L"\fInormalize()\fR\*(R" method will also renormalize the \*(L"months\*(R" | |
1019 | value, if and only if accurate mode has been switched off. (!) | |
1020 | .Sp | |
1021 | (Hence, switch accurate mode \fB\s-1ON\s0\fR temporarily if you \fB\s-1DON\s0'T\fR want | |
1022 | the renormalization of the \*(L"months\*(R" value to happen.) | |
1023 | .Sp | |
1024 | If you want to force the time values from the example above back into | |
1025 | their proper ranges, use the \*(L"\fInormalize()\fR\*(R" method as follows: | |
1026 | .Sp | |
1027 | .Vb 3 | |
1028 | \& print "[$delta]\en"; | |
1029 | \& $delta->normalize(); | |
1030 | \& print "[$delta]\en"; | |
1031 | .Ve | |
1032 | .Sp | |
1033 | This will print | |
1034 | .Sp | |
1035 | .Vb 2 | |
1036 | \& [+0 +0 +0 +3 +84 +55] | |
1037 | \& [+0 +0 +0 +4 +24 +55] | |
1038 | .Ve | |
1039 | .Sp | |
1040 | for the first and | |
1041 | .Sp | |
1042 | .Vb 2 | |
1043 | \& [+0 +0 +0 +3 -26 +45] | |
1044 | \& [+0 +0 +0 +2 +34 +45] | |
1045 | .Ve | |
1046 | .Sp | |
1047 | for the second delta vector from the example further above. | |
1048 | .Sp | |
1049 | Note that the values for days, hours, minutes and seconds are | |
1050 | guaranteed to have the same sign after the renormalization. | |
1051 | .Sp | |
1052 | Under \*(L"normal\*(R" circumstances, i.e., when accurate mode is on (the | |
1053 | default), this method only has an effect on the time part of the | |
1054 | delta vector. | |
1055 | .Sp | |
1056 | If the delta vector in question does not have a time part, nothing | |
1057 | is done. | |
1058 | .Sp | |
1059 | If accurate mode is off, the \*(L"months\*(R" value is also normalized, | |
1060 | i.e., if it lies outside of the range \f(CW\*(C`[\-11..11]\*(C'\fR, integer | |
1061 | multiples of 12 are added to the \*(L"years\*(R" value and subtracted | |
1062 | from the \*(L"months\*(R" value. Moreover, the \*(L"months\*(R" value is | |
1063 | guaranteed to have the same sign as the values for days, | |
1064 | hours, minutes and seconds, unless the \*(L"months\*(R" value is zero | |
1065 | or the values for days, hours, minutes and seconds are all zero. | |
1066 | .Sp | |
1067 | If the object in question is a date and if warnings are enabled, | |
1068 | the message \*(L"normalizing a date is a no\-op\*(R" will be printed to | |
1069 | \&\s-1STDERR\s0. | |
1070 | .Sp | |
1071 | If the object in question is not a valid \*(L"Date::Calc\*(R" object, | |
1072 | nothing is done. | |
1073 | .Sp | |
1074 | The method returns its object's reference, which allows chaining | |
1075 | of method calls, as in the following example: | |
1076 | .Sp | |
1077 | .Vb 1 | |
1078 | \& @time = $delta->normalize()->time(); | |
1079 | .Ve | |
1080 | .IP "\(bu" 2 | |
1081 | Callback Functions | |
1082 | .Sp | |
1083 | Note that you are not restricted to the built-in formats | |
1084 | (numbered from 0 to 2 for \*(L"\fInumber_format()\fR\*(R" and \*(L"\fInumber()\fR\*(R" | |
1085 | and from 0 to 3 for \*(L"\fIdelta_format()\fR\*(R", \*(L"\fIdate_format()\fR\*(R" and | |
1086 | \&\*(L"\fIstring()\fR\*(R") for converting a date or delta object into a | |
1087 | number or string. | |
1088 | .Sp | |
1089 | You can also provide your own function(s) for doing so, in | |
1090 | order to suit your own taste or needs, by passing a subroutine | |
1091 | reference to the appropriate method, i.e., \*(L"\fInumber_format()\fR\*(R", | |
1092 | \&\*(L"\fInumber()\fR\*(R", \*(L"\fIdelta_format()\fR\*(R", \*(L"\fIdate_format()\fR\*(R" and \*(L"\fIstring()\fR\*(R". | |
1093 | .Sp | |
1094 | You can pass a handler to only one or more of these methods, | |
1095 | or to all of them, as you like. You can use different callback | |
1096 | functions, or the same for all. | |
1097 | .Sp | |
1098 | In order to facilitate the latter, and in order to make the | |
1099 | decoding of the various cases easier for you, the callback | |
1100 | function receives a uniquely identifying function code as | |
1101 | its second parameter: | |
1102 | .Sp | |
1103 | .Vb 8 | |
1104 | \& 0 = TO_NUMBER | IS_DATE | IS_SHORT (number[_format]) | |
1105 | \& 1 = TO_NUMBER | IS_DATE | IS_LONG (number[_format]) | |
1106 | \& 2 = TO_NUMBER | IS_DELTA | IS_SHORT (number[_format]) | |
1107 | \& 3 = TO_NUMBER | IS_DELTA | IS_LONG (number[_format]) | |
1108 | \& 4 = TO_STRING | IS_DATE | IS_SHORT (string|date_format) | |
1109 | \& 5 = TO_STRING | IS_DATE | IS_LONG (string|date_format) | |
1110 | \& 6 = TO_STRING | IS_DELTA | IS_SHORT (string|delta_format) | |
1111 | \& 7 = TO_STRING | IS_DELTA | IS_LONG (string|delta_format) | |
1112 | .Ve | |
1113 | .Sp | |
1114 | The first parameter of the callback function is of course the | |
1115 | handle of the object in question itself (therefore, the callback | |
1116 | function can actually be an object method \- but not a class method, | |
1117 | for obvious reasons). | |
1118 | .Sp | |
1119 | The handler should return the resulting number or string, as | |
1120 | requested. | |
1121 | .Sp | |
1122 | \&\s-1BEWARE\s0 that you should \s-1NEVER\s0 rely upon any knowledge of the | |
1123 | object's internal structure, as this may be subject to change! | |
1124 | .Sp | |
1125 | \&\s-1ALWAYS\s0 use the test and access methods provided by this module! | |
1126 | .Sp | |
1127 | Example: | |
1128 | .Sp | |
1129 | .Vb 3 | |
1130 | \& sub handler | |
1131 | \& { | |
1132 | \& my($self,$code) = @_; | |
1133 | .Ve | |
1134 | .Sp | |
1135 | .Vb 48 | |
1136 | \& if ($code == 0) # TO_NUMBER | IS_DATE | IS_SHORT | |
1137 | \& { | |
1138 | \& return Date_to_Days( $self->date() ); | |
1139 | \& } | |
1140 | \& elsif ($code == 1) # TO_NUMBER | IS_DATE | IS_LONG | |
1141 | \& { | |
1142 | \& return Date_to_Days( $self->date() ) + | |
1143 | \& ( ( $self->hours() * 60 + | |
1144 | \& $self->minutes() ) * 60 + | |
1145 | \& $self->seconds() ) / 86400; | |
1146 | \& } | |
1147 | \& elsif ($code == 2) # TO_NUMBER | IS_DELTA | IS_SHORT | |
1148 | \& { | |
1149 | \& return ( $self->year() * 12 + | |
1150 | \& $self->month() ) * 31 + | |
1151 | \& $self->day(); | |
1152 | \& } | |
1153 | \& elsif ($code == 3) # TO_NUMBER | IS_DELTA | IS_LONG | |
1154 | \& { | |
1155 | \& return ( $self->year() * 12 + | |
1156 | \& $self->month() ) * 31 + | |
1157 | \& $self->day() + | |
1158 | \& ( ( $self->hours() * 60 + | |
1159 | \& $self->minutes() ) * 60 + | |
1160 | \& $self->seconds() ) / 86400; | |
1161 | \& } | |
1162 | \& elsif ($code == 4) # TO_STRING | IS_DATE | IS_SHORT | |
1163 | \& { | |
1164 | \& return join( "/", $self->date() ); | |
1165 | \& } | |
1166 | \& elsif ($code == 5) # TO_STRING | IS_DATE | IS_LONG | |
1167 | \& { | |
1168 | \& return join( "/", $self->date() ) . " " . | |
1169 | \& join( ":", $self->time() ); | |
1170 | \& } | |
1171 | \& elsif ($code == 6) # TO_STRING | IS_DELTA | IS_SHORT | |
1172 | \& { | |
1173 | \& return join( "|", $self->date() ); | |
1174 | \& } | |
1175 | \& elsif ($code == 7) # TO_STRING | IS_DELTA | IS_LONG | |
1176 | \& { | |
1177 | \& return join( "|", $self->datetime() ); | |
1178 | \& } | |
1179 | \& else | |
1180 | \& { | |
1181 | \& die "internal error"; | |
1182 | \& } | |
1183 | \& } | |
1184 | .Ve | |
1185 | .Sp | |
1186 | .Vb 3 | |
1187 | \& Date::Calc->number_format(\e&handler); | |
1188 | \& Date::Calc->delta_format(\e&handler); | |
1189 | \& Date::Calc->date_format(\e&handler); | |
1190 | .Ve | |
1191 | .Sp | |
1192 | This sets our handler to take care of all automatic conversions, | |
1193 | such as needed when comparing dates or when interpolating a string | |
1194 | in double quotes which contains a date object. | |
1195 | .Sp | |
1196 | To deactivate a handler, simply pass a valid format number to the | |
1197 | method in question, e.g.: | |
1198 | .Sp | |
1199 | .Vb 3 | |
1200 | \& Date::Calc->number_format(0); | |
1201 | \& Date::Calc->delta_format(2); | |
1202 | \& Date::Calc->date_format(3); | |
1203 | .Ve | |
1204 | .Sp | |
1205 | When calling the \*(L"\fInumber()\fR\*(R" or \*(L"\fIstring()\fR\*(R" method explicitly, you can | |
1206 | pass a different format number (than the global setting), like this: | |
1207 | .Sp | |
1208 | .Vb 2 | |
1209 | \& $number = $date->number(2); | |
1210 | \& $string = $date->string(1); | |
1211 | .Ve | |
1212 | .Sp | |
1213 | You can also pass a handler's reference, like so: | |
1214 | .Sp | |
1215 | .Vb 2 | |
1216 | \& $number = $date->number(\e&handler); | |
1217 | \& $string = $date->string(\e&handler); | |
1218 | .Ve | |
1219 | .Sp | |
1220 | This overrides the global setting for the duration of the call of | |
1221 | \&\*(L"\fInumber()\fR\*(R" or \*(L"\fIstring()\fR\*(R" (but doesn't change the global setting | |
1222 | itself). | |
1223 | .Sp | |
1224 | Moreover, you can also define individual overrides for the date and | |
1225 | the delta vector formats (but not the number format) for individual | |
1226 | objects, e.g.: | |
1227 | .Sp | |
1228 | .Vb 2 | |
1229 | \& $date->delta_format(1); | |
1230 | \& $date->date_format(2); | |
1231 | .Ve | |
1232 | .Sp | |
1233 | .Vb 2 | |
1234 | \& $date->delta_format(\e&handler); | |
1235 | \& $date->date_format(\e&handler); | |
1236 | .Ve | |
1237 | .Sp | |
1238 | In order to deactivate an individual handler for an object, and/or | |
1239 | in order to deactivate any override altogether (so that the global | |
1240 | settings apply again), you have to pass \*(L"undef\*(R" explicitly to the | |
1241 | method in question: | |
1242 | .Sp | |
1243 | .Vb 2 | |
1244 | \& $date->delta_format(undef); | |
1245 | \& $date->date_format(undef); | |
1246 | .Ve | |
1247 | .Sp | |
1248 | You can also define a language for individual objects (see the | |
1249 | next section immediately below for more details). | |
1250 | .Sp | |
1251 | If such an individual language override has been set, and if your | |
1252 | callback handlers only use the \*(L"*_to_Text*\*(R" functions from the | |
1253 | \&\*(L"Date::Calc\*(R" module to produce any text, the text produced will | |
1254 | automatically be in the desired language. | |
1255 | .Sp | |
1256 | This is because the language is set to the value determined by | |
1257 | the individual override before the callback handler is executed, | |
1258 | and reset to its previous value afterwards. | |
1259 | .IP "\(bu" 2 | |
1260 | Languages | |
1261 | .Sp | |
1262 | Note that this module is completely transparent to the setting | |
1263 | of a language in \*(L"Date::Calc\*(R". This means that you can choose a | |
1264 | language in \*(L"Date::Calc\*(R" (with the \*(L"\fILanguage()\fR\*(R" function) and all | |
1265 | dates subsequently printed by this module will automatically be | |
1266 | in that language \- provided that you use the built-in formats of | |
1267 | this module, or that you use the \*(L"*to_Text*\*(R" functions from the | |
1268 | \&\*(L"Date::Calc\*(R" module in your formatting handler (callback function). | |
1269 | .Sp | |
1270 | However, this global language setting can be overridden for | |
1271 | individual date (or delta) objects by using the \fB\s-1OBJECT\s0\fR method | |
1272 | .Sp | |
1273 | .Vb 1 | |
1274 | \& $oldlang = $date->language($newlang); | |
1275 | .Ve | |
1276 | .Sp | |
1277 | (The global setting is not altered by this in any way.) | |
1278 | .Sp | |
1279 | In order to deactivate such an individual language setting | |
1280 | (so that the global setting applies again), simply pass the | |
1281 | value \*(L"undef\*(R" explicitly to the \*(L"\fIlanguage()\fR\*(R" object method: | |
1282 | .Sp | |
1283 | .Vb 1 | |
1284 | \& $date->language(undef); | |
1285 | .Ve | |
1286 | .Sp | |
1287 | The \fB\s-1CLASS\s0\fR method | |
1288 | .Sp | |
1289 | .Vb 1 | |
1290 | \& $oldlang = Date::Calc->language($newlang); | |
1291 | .Ve | |
1292 | .Sp | |
1293 | is just a convenient wrapper around the \*(L"\fILanguage()\fR\*(R" function, | |
1294 | which allows you to enter language numbers (as returned by the | |
1295 | \&\*(L"\fIDecode_Language()\fR\*(R" function) or strings (as returned by the | |
1296 | \&\*(L"\fILanguage_to_Text()\fR\*(R" function), at your option. | |
1297 | .Sp | |
1298 | The \*(L"\fIlanguage()\fR\*(R" method (both class and object) always returns | |
1299 | the \fB\s-1NAME\s0\fR (one of "\f(CW\*(C`Language_to_Text(1..Languages())\*(C'\fR") of | |
1300 | the current setting (and never its number). | |
1301 | .IP "\(bu" 2 | |
1302 | Exported Functions | |
1303 | .Sp | |
1304 | The \*(L"Date::Calc::Object\*(R" package imports \*(L":all\*(R" functions exported | |
1305 | by the \*(L"Date::Calc\*(R" module and re-exports them, for conveniency. | |
1306 | .Sp | |
1307 | This allows you to write | |
1308 | .Sp | |
1309 | .Vb 1 | |
1310 | \& use Date::Calc::Object qw(...); | |
1311 | .Ve | |
1312 | .Sp | |
1313 | instead of | |
1314 | .Sp | |
1315 | .Vb 1 | |
1316 | \& use Date::Calc qw(...); | |
1317 | .Ve | |
1318 | .Sp | |
1319 | but with exactly the same semantics. The difference is that | |
1320 | the object-oriented frontend is loaded additionally in the | |
1321 | first case. | |
1322 | .Sp | |
1323 | As with \*(L"Date::Calc\*(R" you can use the \*(L":all\*(R" tag to import all | |
1324 | of \*(L"Date::Calc\*(R"'s functions: | |
1325 | .Sp | |
1326 | .Vb 1 | |
1327 | \& use Date::Calc::Object qw(:all); | |
1328 | .Ve | |
1329 | .Sp | |
1330 | In addition to the functions exported by \*(L"Date::Calc\*(R", the | |
1331 | \&\*(L"Date::Calc::Object\*(R" package offers some utility functions | |
1332 | of its own for export: | |
1333 | .Sp | |
1334 | .Vb 4 | |
1335 | \& $year = shift_year(\e@_); | |
1336 | \& ($year,$mm,$dd) = shift_date(\e@_); | |
1337 | \& ($hrs,$min,$sec) = shift_time(\e@_); | |
1338 | \& ($year,$mm,$dd,$hrs,$min,$sec) = shift_datetime(\e@_); | |
1339 | .Ve | |
1340 | .Sp | |
1341 | These functions enable your subroutines or methods to accept | |
1342 | a \*(L"Date::Calc\*(R" (or subclass) date object, an (anonymous) array | |
1343 | or a list (containing the necessary values) as parameters | |
1344 | \&\fB\s-1INTERCHANGEABLY\s0\fR. | |
1345 | .Sp | |
1346 | You can import all of these auxiliary functions by using an | |
1347 | \&\*(L":aux\*(R" tag: | |
1348 | .Sp | |
1349 | .Vb 1 | |
1350 | \& use Date::Calc::Object qw(:aux); | |
1351 | .Ve | |
1352 | .Sp | |
1353 | If you want to import both all of the \*(L"Date::Calc\*(R" functions | |
1354 | as well as all these auxiliary functions, use the \*(L":ALL\*(R" tag: | |
1355 | .Sp | |
1356 | .Vb 1 | |
1357 | \& use Date::Calc::Object qw(:ALL); | |
1358 | .Ve | |
1359 | .IP "\(bu" 2 | |
1360 | Subclassing | |
1361 | .Sp | |
1362 | In case you want to subclass \*(L"Date::Calc\*(R" objects and to add | |
1363 | new attributes of your own, it is recommended that you proceed | |
1364 | as follows (the following will be considered as a part of the | |
1365 | module's \*(L"contract of use\*(R" \- which might be subject to change | |
1366 | in the future, however): | |
1367 | .Sp | |
1368 | Define a constant for the index of each attribute you want to | |
1369 | add, currently starting no lower than \*(L"4\*(R", at the top of your | |
1370 | subclass: | |
1371 | .Sp | |
1372 | .Vb 4 | |
1373 | \& use constant ATTRIB1 => 4; | |
1374 | \& use constant ATTRIB2 => 5; | |
1375 | \& use constant ATTRIB3 => 6; | |
1376 | \& ... | |
1377 | .Ve | |
1378 | .Sp | |
1379 | It is recommended that you use constants (which are easy to | |
1380 | change), because I someday might want to require the element | |
1381 | with index \*(L"4\*(R" for a new attribute of my own... \f(CW\*(C`:\-)\*(C'\fR | |
1382 | .Sp | |
1383 | Then access your attributes like so (e.g. after calling | |
1384 | "\f(CW\*(C`$self = SUPER\->new();\*(C'\fR" in your constructor method): | |
1385 | .Sp | |
1386 | .Vb 4 | |
1387 | \& $self->[0][ATTRIB1] = 'value1'; | |
1388 | \& $self->[0][ATTRIB2] = 'value2'; | |
1389 | \& $self->[0][ATTRIB3] = 'value3'; | |
1390 | \& ... | |
1391 | .Ve | |
1392 | .Sp | |
1393 | Beware that if you put anything other than numbers or strings | |
1394 | into your attributes, the methods \*(L"\fIclone()\fR\*(R" and \*(L"\fIcopy()\fR\*(R" might | |
1395 | not work as expected anymore! | |
1396 | .Sp | |
1397 | Especially if your attributes contain references to other data | |
1398 | structures, only the references will be copied, but not the data | |
1399 | structures themselves. | |
1400 | .Sp | |
1401 | This may not be what you want. | |
1402 | .Sp | |
1403 | (You will have to override these two methods and write some | |
1404 | of your own if not.) | |
1405 | .Sp | |
1406 | In order for the overloaded operators and the \*(L"shift_*()\*(R" | |
1407 | auxiliary functions from the \*(L"Date::Calc::Object\*(R" package | |
1408 | to work properly (the latter of which are heavily used in | |
1409 | the \*(L"Date::Calendar[::Year]\*(R" modules, for instance), the | |
1410 | package name of your subclass (= the one your objects will | |
1411 | be blessed into) is \fB\s-1REQUIRED\s0\fR to contain a \*(L"::\*(R". | |
1412 | .Sp | |
1413 | Note that you should \fB\s-1ONLY\s0\fR subclass \*(L"Date::Calc\*(R", \fB\s-1NEVER\s0\fR | |
1414 | \&\*(L"Date::Calc::Object\*(R", since subclassing the latter is less | |
1415 | efficient (because \*(L"Date::Calc::Object\*(R" is just an empty class | |
1416 | which inherits from \*(L"Date::Calc\*(R" \- subclassing \*(L"Date::Calc::Object\*(R" | |
1417 | would thus just introduce an additional name space layer to search | |
1418 | during Perl's runtime method binding process). | |
1419 | .Sp | |
1420 | If you give your subclass a package name below/inside the | |
1421 | \&\*(L"Date::\*(R" namespace, you will also benefit from the fact that | |
1422 | all error messages produced by the \*(L"Date::Calc[::Object]\*(R" module | |
1423 | (and also the \*(L"Date::Calendar[::Year]\*(R" modules, by the way) | |
1424 | will appear to have originated from the place outside of all | |
1425 | "\f(CW\*(C`/^Date::/\*(C'\fR\*(L" modules (including yours) where one of the \*(R"Date::\*(L" | |
1426 | modules was first called \- i.e., all errors are always blamed | |
1427 | on the user, no matter how deeply nested inside the \*(R"Date::\*(L" | |
1428 | modules they occur, and do not usually refer to places inside | |
1429 | any of the \*(R"Date::\*(L" modules (this assumes that there are no | |
1430 | bugs in the \*(R"Date::" modules, and that all errors are always | |
1431 | the user's fault \f(CW\*(C`:\-)\*(C'\fR). | |
1432 | .Sp | |
1433 | Moreover, your module's own error messages will behave in the | |
1434 | same way if you "\f(CW\*(C`use Carp::Clan qw(^Date::);\*(C'\fR\*(L" at the top of | |
1435 | your module and if you produce all error messages using \*(R"\fIcarp()\fR\*(L" | |
1436 | and \*(R"\fIcroak()\fR\*(L" (instead of \*(R"\fIwarn()\fR\*(L" and \*(R"\fIdie()\fR", respectively). | |
1437 | .SH "EXAMPLES" | |
1438 | .IX Header "EXAMPLES" | |
1439 | .IP "1)" 3 | |
1440 | .Vb 7 | |
1441 | \& # Switch to summer time: | |
1442 | \& $now = Date::Calc->now(); | |
1443 | \& if (($now ge [2000,3,26,2,0,0]) and | |
1444 | \& ($now lt [2000,3,26,3,0,0])) | |
1445 | \& { | |
1446 | \& $now += [0,0,0,1,0,0]; | |
1447 | \& } | |
1448 | .Ve | |
1449 | .IP "2)" 3 | |
1450 | .Vb 1 | |
1451 | \& use Date::Calc::Object qw(:all); | |
1452 | .Ve | |
1453 | .Sp | |
1454 | .Vb 1 | |
1455 | \& Date::Calc->date_format(3); | |
1456 | .Ve | |
1457 | .Sp | |
1458 | .Vb 21 | |
1459 | \& $date = 0; | |
1460 | \& while (!$date) | |
1461 | \& { | |
1462 | \& print "Please enter the date of your birthday (day-month-year): "; | |
1463 | \& $date = Date::Calc->new( Decode_Date_EU( scalar(<STDIN>) ) ); | |
1464 | \& if ($date) | |
1465 | \& { | |
1466 | \& $resp = 0; | |
1467 | \& while ($resp !~ /^\es*[YyNn]/) | |
1468 | \& { | |
1469 | \& print "Your birthday is: $date\en"; | |
1470 | \& print "Is that correct? (yes/no) "; | |
1471 | \& $resp = <STDIN>; | |
1472 | \& } | |
1473 | \& $date = 0 unless ($resp =~ /^\es*[Yy]/) | |
1474 | \& } | |
1475 | \& else | |
1476 | \& { | |
1477 | \& print "Unable to parse your birthday. Please try again.\en"; | |
1478 | \& } | |
1479 | \& } | |
1480 | .Ve | |
1481 | .Sp | |
1482 | .Vb 4 | |
1483 | \& if ($date + [18,0,0] <= [Today()]) | |
1484 | \& { print "Ok, you are over 18.\en"; } | |
1485 | \& else | |
1486 | \& { print "Sorry, you are under 18!\en"; } | |
1487 | .Ve | |
1488 | .PP | |
1489 | For more examples, see the \*(L"examples\*(R" subdirectory in this distribution, | |
1490 | and their descriptions in the file \*(L"\s-1EXAMPLES\s0.txt\*(R". | |
1491 | .SH "SEE ALSO" | |
1492 | .IX Header "SEE ALSO" | |
1493 | \&\fIDate::Calc\fR\|(3), \fIDate::Calendar\fR\|(3), | |
1494 | \&\fIDate::Calendar::Year\fR\|(3), \fIDate::Calendar::Profiles\fR\|(3). | |
1495 | .SH "VERSION" | |
1496 | .IX Header "VERSION" | |
1497 | This man page documents \*(L"Date::Calc::Object\*(R" version 5.3. | |
1498 | .SH "AUTHOR" | |
1499 | .IX Header "AUTHOR" | |
1500 | .Vb 3 | |
1501 | \& Steffen Beyer | |
1502 | \& mailto:sb@engelschall.com | |
1503 | \& http://www.engelschall.com/u/sb/download/ | |
1504 | .Ve | |
1505 | .SH "COPYRIGHT" | |
1506 | .IX Header "COPYRIGHT" | |
1507 | Copyright (c) 2000 \- 2002 by Steffen Beyer. All rights reserved. | |
1508 | .SH "LICENSE" | |
1509 | .IX Header "LICENSE" | |
1510 | This package is free software; you can redistribute it and/or | |
1511 | modify it under the same terms as Perl itself, i.e., under the | |
1512 | terms of the \*(L"Artistic License\*(R" or the \*(L"\s-1GNU\s0 General Public License\*(R". | |
1513 | .PP | |
1514 | Please refer to the files \*(L"Artistic.txt\*(R" and \*(L"\s-1GNU_GPL\s0.txt\*(R" | |
1515 | in this distribution for details! | |
1516 | .SH "DISCLAIMER" | |
1517 | .IX Header "DISCLAIMER" | |
1518 | This package is distributed in the hope that it will be useful, | |
1519 | but \s-1WITHOUT\s0 \s-1ANY\s0 \s-1WARRANTY\s0; without even the implied warranty of | |
1520 | \&\s-1MERCHANTABILITY\s0 or \s-1FITNESS\s0 \s-1FOR\s0 A \s-1PARTICULAR\s0 \s-1PURPOSE\s0. | |
1521 | .PP | |
1522 | See the \*(L"\s-1GNU\s0 General Public License\*(R" for more details. |