1/* Part of SWI-Prolog 2 3 Author: Jan Wielemaker and Willem Robert van Hage 4 E-mail: wielemak@science.uva.nl 5 WWW: http://www.swi-prolog.org 6 Copyright (c) 2006-2024, University of Amsterdam 7 SWI-Prolog Solutions b.v. 8 All rights reserved. 9 10 Redistribution and use in source and binary forms, with or without 11 modification, are permitted provided that the following conditions 12 are met: 13 14 1. Redistributions of source code must retain the above copyright 15 notice, this list of conditions and the following disclaimer. 16 17 2. Redistributions in binary form must reproduce the above copyright 18 notice, this list of conditions and the following disclaimer in 19 the documentation and/or other materials provided with the 20 distribution. 21 22 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 23 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 24 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 25 FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 26 COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 27 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 28 BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 29 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 30 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 32 ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33 POSSIBILITY OF SUCH DAMAGE. 34*/ 35 36:- module(date, 37 [ date_time_value/3, % ?Field, ?DaTime, ?Value 38 parse_time/2, % +Date, -Stamp 39 parse_time/3, % +Date, ?Format, -Stamp 40 day_of_the_week/2, % +Date, -DayOfTheWeek 41 day_of_the_year/2 % +Date, -DayOfTheYear 42 ]).
| year | integer | |
| month | 1..12 | |
| day | 1..31 | |
| hour | 0..23 | |
| minute | 0..59 | |
| second | 0.0..60.0 | |
| utc_offset | integer | Offset to UTC in seconds (positive is west) |
| daylight_saving | bool | Name of timezone; fails if unknown |
| date | date(Y,M,D) | |
| time | time(H,M,S) |
62date_time_value(year, date(Y,_,_,_,_,_,_,_,_), Y). 63date_time_value(month, date(_,M,_,_,_,_,_,_,_), M). 64date_time_value(day, date(_,_,D,_,_,_,_,_,_), D). 65date_time_value(hour, date(_,_,_,H,_,_,_,_,_), H). 66date_time_value(minute, date(_,_,_,_,M,_,_,_,_), M). 67date_time_value(second, date(_,_,_,_,_,S,_,_,_), S). 68date_time_value(utc_offset, date(_,_,_,_,_,_,O,_,_), O). 69date_time_value(time_zone, date(_,_,_,_,_,_,_,Z,_), Z) :- Z \== (-). 70date_time_value(daylight_saving, date(_,_,_,_,_,_,_,_,D), D) :- D \== (-). 71 72date_time_value(date, date(Y,M,D,_,_,_,_,_,_), date(Y,M,D)). 73date_time_value(time, date(_,_,_,H,M,S,_,_,_), time(H,M,S)).
Fri, 08 Dec 2006 15:29:44 GMT
All components except for the time zone are obligatory. If the time zone is omitted, the time is interpreted as local time.
Sunday, 06-Nov-94 08:49:37 GMT
2006-12-08T15:29:44Z
The ISO8601 format allows removing components from the
right, returning the lowest time stamp in the specified
internal. If a time is specified but no time zone, the
time stamp is computed for the local time. If only
the date components are specified, the stamp uses UTC.
To compute the start of a day in local time, use
e.g. 2006-12-08T00.
asctime() format, e.g.
Sun Nov 6 08:49:37 1994
This format has no time zone and is interpreted as local time.
121parse_time(Text, Stamp) :- 122 parse_time(Text, _Format, Stamp). 123 124parse_time(Text, Format, Stamp) :- 125 to_codes(Text, Codes), 126 phrase(date(Format, Y,Mon,D,H,Min,S,UTCOffset), Codes), 127 !, 128 tz_dst(time(H,Min,S), UTCOffset, TZ, DST), 129 date_time_stamp(date(Y,Mon,D,H,Min,S,UTCOffset,TZ,DST), Stamp). 130 131to_codes(In, Codes) :- 132 ( is_list(In) 133 -> Codes = In 134 ; atom_codes(In, Codes) 135 ). 136 137tz_dst(_Time, UTCOffset, TZ, DST), nonvar(UTCOffset) => 138 TZ = (-), DST = (-). 139tz_dst(time(H,M,S), UTCOffset, TZ, DST), var(H), var(M), var(S) => 140 UTCOffset = 0, TZ = (-), DST = (-). 141tz_dst(_, _, _, _) => 142 true. 143 144date(iso_8601, Yr, Mon, D, H, Min, S, UTCOffset) --> % BC 145 "-", date(iso_8601, Y, Mon, D, H, Min, S, UTCOffset), 146 { Yr is -1 * Y }. 147date(iso_8601, Y, Mon, D, H, Min, S, UTCOffset) --> 148 year(Y), 149 iso_8601_rest(Y, Mon, D, H, Min, S, UTCOffset). 150date(rfc_1123, Y, Mon, D, H, M, S, UTCOffset) --> 151 day_name(_), ", ", ws, % RFC 1123: "Fri, 08 Dec 2006 15:29:44 GMT" 152 day_of_the_month(D), ws, 153 month_name(Mon), ws, 154 year(Y), ws, 155 iso_time3(H, M, S), ws, 156 timezone(UTCOffset). 157date(rfc_1036, Y, Mon, D, H, M, S, UTCOffset) --> 158 full_day_name(_), ", ", ws, % RFC 1036: "Friday, 08-Dec-2006 15:29:44 GMT" 159 day_of_the_month(D), "-", 160 month_name(Mon), "-", 161 year2d(Y), ws, 162 iso_time3(H, M, S), ws, 163 timezone(UTCOffset). 164date(asctime, Y, Mon, D, H, M, S, _UTCOffset) --> 165 day_name(_), " ", 166 month_name(Mon), " ", 167 asctime_day_of_the_month(D), " ", 168 iso_time3(H, M, S), " ", 169 year(Y).
175iso_8601_rest(_, Mon, D, H, Min, S, UTCOffset) --> 176 "-", month(Mon), "-", day(D), 177 opt_time(H, Min, S, UTCOffset). 178iso_8601_rest(_, Mon, _, _, _, _, _) --> 179 "-", month(Mon). 180iso_8601_rest(_, Mon, D, H, Min, S, UTCOffset) --> 181 month(Mon), day(D), 182 opt_time(H, Min, S, UTCOffset). 183iso_8601_rest(_, 1, D, H, Min, S, UTCOffset) --> 184 "-", ordinal(D), 185 opt_time(H, Min, S, UTCOffset). 186iso_8601_rest(Yr, 1, D, H, Min, S, UTCOffset) --> 187 "-W", week(W), "-", day_of_the_week(DW), 188 opt_time(H, Min, S, UTCOffset), 189 { week_ordinal(Yr, W, DW, D) }. 190iso_8601_rest(Yr, 1, D, H, Min, S, UTCOffset) --> 191 "W", week(W), day_of_the_week(DW), 192 opt_time(H, Min, S, UTCOffset), 193 { week_ordinal(Yr, W, DW, D) }. 194iso_8601_rest(Yr, 1, D, _, _, _, _) --> 195 "W", week(W), 196 { week_ordinal(Yr, W, 1, D) }. 197 198opt_time(Hr, Min, Sec, UTCOffset) --> 199 ("T";" "), !, iso_time(Hr, Min, Sec), timezone(UTCOffset). 200opt_time(_H, _M, _S, _UTCOffset) --> "". 201 202 203% TIMEX2 ISO: "2006-12-08T15:29:44 UTC" or "20061208T" 204iso_time(H, M, S) --> 205 iso_time3(H, M, S). 206iso_time(H, M, _) --> 207 hour(H), ":", minute(M). 208iso_time(H, M, S) --> 209 hour(H), minute(M), second(S). 210iso_time(H, M, _) --> 211 hour(H), minute(M). 212iso_time(H, _, _) --> 213 hour(H). 214 215iso_time3(H, M, S) --> 216 hour(H), ":", minute(M), ":", second(S). 217 218% FIXME: deal with leap seconds 219timezone(UTCOffset) --> 220 "+", hour(H), ":", minute(M), { UTCOffset is -(H*3600+M*60) }. 221timezone(UTCOffset) --> 222 "+", hour(H), minute(M), { UTCOffset is -(H*3600+M*60) }. 223timezone(UTCOffset) --> 224 "+", hour(H), { UTCOffset is -(H*3600) }. 225timezone(UTCOffset) --> 226 "-", hour(H), ":", minute(M), { UTCOffset is H*3600+M*60 }. 227timezone(UTCOffset) --> 228 "-", hour(H), minute(M), { UTCOffset is H*3600+M*60 }. 229timezone(UTCOffset) --> 230 "-", hour(H), { UTCOffset is H*3600 }. 231timezone(0) --> 232 "Z". 233timezone(0) --> 234 ws, "UTC". 235timezone(0) --> 236 ws, "GMT". 237timezone(_) --> % unknown 238 []. 239 240day_name(0) --> "Sun". 241day_name(1) --> "Mon". 242day_name(2) --> "Tue". 243day_name(3) --> "Wed". 244day_name(4) --> "Thu". 245day_name(5) --> "Fri". 246day_name(6) --> "Sat". 247day_name(7) --> "Sun". 248 249full_day_name(0) --> "Sunday". 250full_day_name(1) --> "Monday". 251full_day_name(2) --> "Tuesday". 252full_day_name(3) --> "Wednesday". 253full_day_name(4) --> "Thursday". 254full_day_name(5) --> "Friday". 255full_day_name(6) --> "Saturday". 256full_day_name(7) --> "Sunday". 257 258month_name(1) --> "Jan". 259month_name(2) --> "Feb". 260month_name(3) --> "Mar". 261month_name(4) --> "Apr". 262month_name(5) --> "May". 263month_name(6) --> "Jun". 264month_name(7) --> "Jul". 265month_name(8) --> "Aug". 266month_name(9) --> "Sep". 267month_name(10) --> "Oct". 268month_name(11) --> "Nov". 269month_name(12) --> "Dec". 270 271asctime_day_of_the_month(D) --> 272 " ", !, digit(D), {D > 0}. 273asctime_day_of_the_month(D) --> 274 day_of_the_month(D). 275 276day_of_the_month(N) --> int2digit(N), { between(1, 31, N) }. 277day_of_the_week(N) --> digit(N), { between(1, 7, N) }. 278month(M) --> int2digit(M), { between(1, 12, M) }. 279week(W) --> int2digit(W), { between(1, 53, W) }. 280day(D) --> int2digit(D), { between(1, 31, D) }. 281hour(N) --> int2digit(N), { between(0, 23, N) }. 282minute(N) --> int2digit(N), { between(0, 59, N) }. 283second(S) --> int2digit(N), { between(0, 60, N) }, % leap second 284 opt_fraction(N, S). 285 286opt_fraction(I, F) --> 287 ( "." ; "," ), 288 !, 289 digits(D), 290 { length(D, N), 291 N > 0, 292 number_codes(FP, D), 293 F is I + FP/(10^N) 294 }. 295opt_fraction(I, I) --> 296 []. 297 298int2digit(N) --> 299 digit(D0), 300 digit(D1), 301 { N is D0*10+D1 }. 302 303year(Y) --> 304 digit(D0), 305 digit(D1), 306 digit(D2), 307 digit(D3), 308 { Y is D0*1000+D1*100+D2*10+D3 }. 309 310year2d(Y) --> 311 digit(D0), 312 digit(D1), 313 { Y0 is D0*10+D1, 314 ( Y0 >= 70, Y0 =< 99 315 -> Y is Y0+1900 316 ; Y is Y0+2000 317 ) 318 }. 319 320ordinal(N) --> % Nth day of the year, jan 1 = 1, dec 31 = 365 or 366 321 digit(D0), 322 digit(D1), 323 digit(D2), 324 { N is D0*100+D1*10+D2, between(1, 366, N) }. 325 326digit(D) --> 327 [C], 328 { code_type(C, digit(D)) }. 329 330digits([C|T]) --> 331 [C], 332 { code_type(C, digit) }, 333 !, 334 digits(T). 335digits([]) --> []. 336 337ws --> 338 " ", 339 !, 340 ws. 341ws --> 342 [].
352day_of_the_week(date(Year, Mon, Day), DotW) :- 353 format_time(atom(A), '%u', date(Year, Mon, Day, 0, 0, 0, 0, -, -)), 354 atom_number(A, DotW). 355 356week_ordinal(Year, Week, Day, Ordinal) :- 357 format_time(atom(A), '%w', date(Year, 1, 1, 0, 0, 0, 0, -, -)), 358 atom_number(A, DotW0), 359 Ordinal is ((Week-1) * 7) - DotW0 + Day + 1.
368day_of_the_year(date(Year, Mon, Day), DotY) :-
369 format_time(atom(A), '%j', date(Year, Mon, Day, 0, 0, 0, 0, -, -)),
370 atom_number(A, DotY)
Process dates and times
*/