/* Part of SWI-Prolog Author: Jan Wielemaker and Willem Robert van Hage E-mail: wielemak@science.uva.nl WWW: http://www.swi-prolog.org Copyright (c) 2006-2014, University of Amsterdam All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ :- module(date, [ date_time_value/3, % ?Field, ?DaTime, ?Value parse_time/2, % +Date, -Stamp parse_time/3, % +Date, ?Format, -Stamp day_of_the_week/2, % +Date, -DayOfTheWeek day_of_the_year/2 % +Date, -DayOfTheYear ]). /** Process dates and times */ %! date_time_value(?Field:atom, +Struct:datime, -Value) is nondet. % % Extract values from a date-time structure. Provided fields are % % | 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) | | date_time_value(year, date(Y,_,_,_,_,_,_,_,_), Y). date_time_value(month, date(_,M,_,_,_,_,_,_,_), M). date_time_value(day, date(_,_,D,_,_,_,_,_,_), D). date_time_value(hour, date(_,_,_,H,_,_,_,_,_), H). date_time_value(minute, date(_,_,_,_,M,_,_,_,_), M). date_time_value(second, date(_,_,_,_,_,S,_,_,_), S). date_time_value(utc_offset, date(_,_,_,_,_,_,O,_,_), O). date_time_value(time_zone, date(_,_,_,_,_,_,_,Z,_), Z) :- Z \== (-). date_time_value(daylight_saving, date(_,_,_,_,_,_,_,_,D), D) :- D \== (-). date_time_value(date, date(Y,M,D,_,_,_,_,_,_), date(Y,M,D)). date_time_value(time, date(_,_,_,H,M,S,_,_,_), time(H,M,S)). %! parse_time(+Text, -Stamp) is semidet. %! parse_time(+Text, ?Format, -Stamp) is semidet. % % Stamp is a timestamp created from parsing Text using the % representation Format. Currently supported formats are: % % * rfc_1123 % Used for the HTTP protocol to represent time-stamps % * iso_8601 % Commonly used in XML documents. parse_time(Text, Stamp) :- parse_time(Text, _Format, Stamp). parse_time(Text, Format, Stamp) :- atom_codes(Text, Codes), phrase(date(Format, Y,Mon,D,H,Min,S,UTCOffset), Codes), !, date_time_stamp(date(Y,Mon,D,H,Min,S,UTCOffset,-,-), Stamp). date(iso_8601, Yr, Mon, D, H, Min, S, 0) --> % BC "-", date(iso_8601, Y, Mon, D, H, Min, S, 0), { Yr is -1 * Y }. date(iso_8601, Y, Mon, D, H, Min, S, 0) --> year(Y), iso_8601_rest(Y, Mon, D, H, Min, S). date(rfc_1123, Y, Mon, D, Hr, Min, Sec, 0) --> % RFC 1123: "Fri, 08 Dec 2006 15:29:44 GMT" day_name(_), ", ", ws, day_of_the_month(D), ws, month_name(Mon), ws, year(Y), ws, hour(H), ":", minute(M), ":", second(S), ws, timezone(DH, DM, DS), { Hr is H + DH, Min is M + DM, Sec is S + DS }. %! iso_8601_rest(+Year:int, -Mon, -Day, -H, -M, -S) % % Process ISO 8601 time-values after parsing the 4-digit year. iso_8601_rest(_, Mon, D, H, Min, S) --> "-", month(Mon), "-", day(D), opt_time(H, Min, S). iso_8601_rest(_, Mon, 0, 0, 0, 0) --> "-", month(Mon). iso_8601_rest(_, Mon, D, H, Min, S) --> month(Mon), day(D), opt_time(H, Min, S). iso_8601_rest(_, 1, D, H, Min, S) --> "-", ordinal(D), opt_time(H, Min, S). iso_8601_rest(Yr, 1, D, H, Min, S) --> "-W", week(W), "-", day_of_the_week(DW), opt_time(H, Min, S), { week_ordinal(Yr, W, DW, D) }. iso_8601_rest(Yr, 1, D, H, Min, S) --> "W", week(W), day_of_the_week(DW), opt_time(H, Min, S), { week_ordinal(Yr, W, DW, D) }. iso_8601_rest(Yr, 1, D, 0, 0, 0) --> "W", week(W), { week_ordinal(Yr, W, 1, D) }. opt_time(Hr, Min, Sec) --> ("T";" "), !, iso_time(Hr, Min, Sec). opt_time(0, 0, 0) --> "". % TIMEX2 ISO: "2006-12-08T15:29:44 UTC" or "20061208T" iso_time(Hr, Min, Sec) --> hour(H), ":", minute(M), ":", second(S), timezone(DH, DM, DS), { Hr is H + DH, Min is M + DM, Sec is S + DS }. iso_time(Hr, Min, Sec) --> hour(H), ":", minute(M), timezone(DH, DM, DS), { Hr is H + DH, Min is M + DM, Sec is DS }. iso_time(Hr, Min, Sec) --> hour(H), minute(M), second(S), timezone(DH, DM, DS), { Hr is H + DH, Min is M + DM, Sec is S + DS }. iso_time(Hr, Min, Sec) --> hour(H), minute(M), timezone(DH, DM, DS), { Hr is H + DH, Min is M + DM, Sec is DS }. iso_time(Hr, Min, Sec) --> hour(H), timezone(DH, DM, DS), { Hr is H + DH, Min is DM, Sec is DS }. % FIXME: deal with leap seconds timezone(Hr, Min, 0) --> "+", hour(H), ":", minute(M), { Hr is -1 * H, Min is -1 * M }. timezone(Hr, Min, 0) --> "+", hour(H), minute(M), { Hr is -1 * H, Min is -1 * M }. timezone(Hr, 0, 0) --> "+", hour(H), { Hr is -1 * H }. timezone(Hr, Min, 0) --> "-", hour(H), ":", minute(M), { Hr is H, Min is M }. timezone(Hr, Min, 0) --> "-", hour(H), minute(M), { Hr is H, Min is M }. timezone(Hr, 0, 0) --> "-", hour(H), { Hr is H }. timezone(0, 0, 0) --> "Z". timezone(0, 0, 0) --> ws, "UTC". timezone(0, 0, 0) --> ws, "GMT". % remove this? timezone(0, 0, 0) --> []. day_name(0) --> "Sun". day_name(1) --> "Mon". day_name(2) --> "Tue". day_name(3) --> "Wed". day_name(4) --> "Thu". day_name(5) --> "Fri". day_name(6) --> "Sat". day_name(7) --> "Sun". month_name(1) --> "Jan". month_name(2) --> "Feb". month_name(3) --> "Mar". month_name(4) --> "Apr". month_name(5) --> "May". month_name(6) --> "Jun". month_name(7) --> "Jul". month_name(8) --> "Aug". month_name(9) --> "Sep". month_name(10) --> "Oct". month_name(11) --> "Nov". month_name(12) --> "Dec". day_of_the_month(N) --> int2digit(N), { between(1, 31, N) }. day_of_the_week(N) --> digit(N), { between(1, 7, N) }. month(M) --> int2digit(M), { between(1, 12, M) }. week(W) --> int2digit(W), { between(1, 53, W) }. day(D) --> int2digit(D), { between(1, 31, D) }. hour(N) --> int2digit(N), { between(0, 23, N) }. minute(N) --> int2digit(N), { between(0, 59, N) }. second(S) --> int2digit(N), { between(0, 60, N) }, % leap second opt_fraction(N, S). opt_fraction(I, F) --> ( "." ; "," ), !, digits(D), { length(D, N), N > 0, number_codes(FP, D), F is I + FP/(10^N) }. opt_fraction(I, I) --> []. int2digit(N) --> digit(D0), digit(D1), { N is D0*10+D1 }. year(Y) --> digit(D0), digit(D1), digit(D2), digit(D3), { Y is D0*1000+D1*100+D2*10+D3 }. ordinal(N) --> % Nth day of the year, jan 1 = 1, dec 31 = 365 or 366 digit(D0), digit(D1), digit(D2), { N is D0*100+D1*10+D2, between(1, 366, N) }. digit(D) --> [C], { code_type(C, digit(D)) }. digits([C|T]) --> [C], { code_type(C, digit) }, !, digits(T). digits([]) --> []. ws --> " ", !, ws. ws --> []. %! day_of_the_week(+Date, -DayOfTheWeek) is det. % % Computes the day of the week for a given date. Days of the week % are numbered from one to seven: monday = 1, tuesday = 2, ..., % sunday = 7. % % @param Date is a term of the form date(+Year, +Month, +Day) day_of_the_week(date(Year, Mon, Day), DotW) :- format_time(atom(A), '%u', date(Year, Mon, Day, 0, 0, 0, 0, -, -)), atom_number(A, DotW). week_ordinal(Year, Week, Day, Ordinal) :- format_time(atom(A), '%w', date(Year, 1, 1, 0, 0, 0, 0, -, -)), atom_number(A, DotW0), Ordinal is ((Week-1) * 7) - DotW0 + Day + 1. %! day_of_the_year(+Date, -DayOfTheYear) is det. % % Computes the day of the year for a given date. Days of the year % are numbered from 1 to 365 (366 for a leap year). % % @param Date is a term of the form date(+Year, +Month, +Day) day_of_the_year(date(Year, Mon, Day), DotY) :- format_time(atom(A), '%j', date(Year, Mon, Day, 0, 0, 0, 0, -, -)), atom_number(A, DotY).