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Documenttype:InternationalStandardDocumentsubtype:Documentstage:(20)PreparatoryStageDocumentlanguage:EDocuments:MyDocuments:Work:ISO-TC154:WG5:N-Documents:ISO-TC154-WG5_N0039_ISO_WD_8601-2_2016-02-16.docxSTDVersion2.7f
ISO/TC154N0039Date:2016-02-16
ISO/WD8601-2
ISO/TC154/WG5
Secretariat:SAC
Dataelementsandinterchangeformats—Informationinterchange-Representationofdatesandtimes—Part2:ExtensionsElémentsdedonnéesetformatsd'échange—Échanged'information-Représentationdeladateetdel'heure—Partie2:Extensions
Warning
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Contents Page
1 Scope..........................................................................................................................................................1
2 Normativereferences..........................................................................................................................13 Termsanddefinitions..........................................................................................................................1
4 DateandTimeExtensions..................................................................................................................24.1 General.......................................................................................................................................................24.2 Uncertainand/orapproximatedate..........................................................................................................24.3 Unspecified................................................................................................................................................44.4 Beforeorafter............................................................................................................................................54.5 Enhancedtimeinterval..............................................................................................................................54.6 Yearexceedingfourdigits..........................................................................................................................64.7 Significantdigits.........................................................................................................................................74.8 Divisionsofayear......................................................................................................................................74.9 Oneofaset................................................................................................................................................84.10 Multipledates..........................................................................................................................................84.11 Decade.....................................................................................................................................................9
5 Repeatrulesforrecurringtimeintervals.....................................................................................95.1 Meansofspecifyingrepeatrules...............................................................................................................95.2 Separatorsanddesignators.....................................................................................................................105.3 Repeatrules.............................................................................................................................................105.4 Frequencyrulepart..................................................................................................................................105.5 Divisionalrulepart...................................................................................................................................105.6 Timeintervalrulepart.............................................................................................................................105.7 Byruleparts.............................................................................................................................................115.8 Completerepresentations.......................................................................................................................135.9 Representationsotherthancomplete.....................................................................................................13
AnnexA(normative)EBNFnotation...................................................................................................14
AnnexB(normative)ISO8601profiles.............................................................................................19B.1 Statementoftheproblem.......................................................................................................................19
AnnexC(informative)TheExtendedDate/TimeFormat-AProfileofISO8601(Parts1and2)............................................................................................................................................................21C.1 Introduction.............................................................................................................................................21
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Foreword
ISO (the International Organization for Standardization) is a worldwide federation of nationalstandards bodies (ISO member bodies). The work of preparing International Standards is normallycarriedout through ISO technical committees.Eachmemberbody interested ina subject forwhichatechnical committee has been established has the right to be represented on that committee.Internationalorganizations,governmentalandnon-governmental,inliaisonwithISO,alsotakepartinthe work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on allmattersofelectrotechnicalstandardization.
The procedures used to develop this document and those intended for its further maintenance aredescribedintheISO/IECDirectives,Part1.InparticularthedifferentapprovalcriterianeededforthedifferenttypesofISOdocumentsshouldbenoted.ThisdocumentwasdraftedinaccordancewiththeeditorialrulesoftheISO/IECDirectives,Part2(seewww.iso.org/directives).
Attentionisdrawntothepossibilitythatsomeoftheelementsofthisdocumentmaybethesubjectofpatentrights. ISOshallnotbeheldresponsiblefor identifyinganyorallsuchpatentrights.DetailsofanypatentrightsidentifiedduringthedevelopmentofthedocumentwillbeintheIntroductionand/orontheISOlistofpatentdeclarationsreceived(seewww.iso.org/patents).
Anytradenameusedinthisdocumentisinformationgivenfortheconvenienceofusersanddoesnotconstituteanendorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformityassessment, as well as information about ISO's adherence to the WTO principles in the TechnicalBarrierstoTrade(TBT)seethefollowingURL:Foreword-Supplementaryinformation
The committee responsible for this document is ISO/154,Processes, data elements and documents incommerce,industryandadministration.
ThisfirsteditionofISO8601-2extendsISO8601-1:2016
ISO8601consistsofthefollowingpart,underthegenerictitleDataelementsandinterchangeformats—Informationinterchange-Representationofdatesandtimes:
— Part1:Basicrules
— Part2:Extensions
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Introduction
TobedevelopedduringtheCommitteeStage
WORKINGDRAFT ISO/WD8601-2
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Dataelementsandinterchangeformats—Informationinterchange-Representationofdatesandtimes—Part2:Extensions
1 Scope
ThisInternationalStandard isapplicablewheneverrepresentationofdates intheGregoriancalendar,timesinthe24-hourtimekeepingsystem,extendingISO8601-1:2016.Itincludes
— calendar dates expressed in terms of calendar year, calendar month and/or calendar day of themonth;
— combinationofdateandtimeofdayincludinglocaltimebaseduponthe24hourtimekeepingsystemandthedifferencefromCoordinatedUniversalTime;
— Uncertainorapproximatedates,ordateswithportionsunspecified.
— timeintervals;
— Divisionsofayear;
— Setsandchoicesofcalendardates;
— repeatrulesforrecurringtimeintervals.
ThisInternationalStandarddoesnotcoverdatesandtimeswherewordsareusedintherepresentationanddatesandtimeswherecharactersarenotusedintherepresentation.
ThisInternationalStandarddoesnotassignanyparticularmeaningorinterpretationtoanydataelementthat uses representations in accordance with this International Standard. Such meaning will bedeterminedbythecontextoftheapplication.
2 Normativereferences
The following documents, inwhole or in part, are normatively referenced in this document and areindispensable for its application. For dated references, only the edition cited applies. For undatedreferences,thelatesteditionofthereferenceddocument(includinganyamendments)applies.
ISO/WD 8601-1:2016, Data elements and interchange formats — Information interchange -Representationofdatesandtimes—Part1:Basicrules
ISO/IEC14977:1996Informationtechnology—Syntacticmetalanguage—ExtendedBNF
3 Termsanddefinitions
Forthepurposesofthisdocument,thefollowingtermsanddefinitions.
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3.1uncertaindatewhosesourceisconsidereddubious
3.2 approximatedatewhichisanestimatewhosevalueisassertedtobepossiblycorrect,andifnot,closetocorrect
Note1toentry: Where'closetocorrect'means"closeenough,fortheapplication".
3.3unspecifiedpart of a datewhich is unstated,which could be because it has not (yet) been assigned (itmight beassignedinthefuture),orbecauseitisclassified,orunknown,orforanyotherreason.Theunspecifiedpartmaybetheyear,yearandmonth,month,monthandday,oryearandday.
4 DateandTimeExtensions
4.1 General
4.1.1 Extendedformat
For featuresdescribed in thispartof ISO8601,Clause4,only theextended format (YYYY-MM-DD) isused.Basicformat(YYYYMMDD)isnottobeused.
4.1.2 Levels
Fortheextensionfeatures,twolevelsaredefined:level1andlevel2.Eachmajorsubsectionofsection4coversageneralfeature;somefunctionscoveredbythatfeaturearelevel1andsomearelevel2.Theselevels are defined for the purpose of profiles, which may refer to the levels when specifyingconformancetotheprofile.ProfilesaredescribedinAnnexB.
4.2 Uncertainand/orapproximatedate
Thecharacter'?'(questionmark)isusedtomean"uncertain".Thecharacter'~'(tilde)isusedtomean"approximate".Thecharacter'%’(percent)isusedtomean“bothuncertainandapproximate".
4.2.1 Level1
Forlevel1,‘?,’‘~’,or‘%’mayonlyoccurattheendofthedatestring,anditappliestotheentiredate.
Format: YYYY-MM-DD? Example:1985-04-12? YYYY-MM-DD~ Example:1985-04-12~ YYYY-MM-DD% Example:1985-04-12%Representationswithreducedaccuracy
a) YearandmonthFormat:YYYY-MM?Example:2004-06?YYYY-MM~Example:1985-04~YYYY-MM%Example:1985-04%
b) YearonlyFormat:YYYY?Example:2004?YYYY~Example:1985~
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YYYY%Example:1985%4.2.2 Level2
Forlevel2,thecharacters‘?’,‘~’,and‘%’maybeusedtoqualifyaportionofthedate(notnecessarilythewholedate).
• Oneofthethreecharactersmayoccurimmediatelytotherightofoneofthedatecomponents,inwhichcaseitappliestothatcomponentaswellasanycomponentstotheleft.Forexampleifitoccursimmediatelytotherightoftheday,itappliestotheday,month,andyear(i.e.theentiredatestring).Ifitoccurstotherightofthemonth,itappliestothemonthandyear(butnottheday).Ifitoccurstotherightoftheyear,itappliestotheyearonly.Examples:
o 2004?-06-11uncertainyear;month,dayknown
o 2004-06~-11yearandmontharebothapproximate;dayknown
o 2004-06%-11yearandmontharebothuncertainandapproximate;dayknown
• Oneofthethreecharactersmayoccurimmediatelytotheleftofoneofthedatecomponents,inwhichcaseitappliesonlytothatcomponent.Forexampleifitoccursimmediatelytotheleftoftheday,itappliesonlytotheday(andnottothemonth,oryear).Ifitoccurstotheleftofthemonth,itappliesonlytothemonth(andnottotheyearorday).Ifitoccurstotheleftoftheyear,itappliesonlytotheyear(andnottothedayormonth)..Examples:
o 2004-?06-11uncertainmonth;yearanddayknown
o 2004-~06-11approximatemonth,yearanddayknown
o 2004-%06-11monthuncertainandapproximate,yearanddayknown
o ?2004-06-?11uncertainyearandday,monthknown
o ?2004-06-~11Yearuncertain,monthknown,dayapproximate
• Theabovetwofeaturesmaybecombinedo 2004-06?-~11
Yearandmonthuncertain(because‘?’istotherightofmonthmeaningthatitappliestomonthaswellascomponentstotheleftofmonth)anddayapproximate
o 2004?-06-~11Samemeaningas?2004-06-~11(earlierexample):Yearuncertain,monthknown,dayapproximate.
GuidelinesTherearecaseswheremorethanonestringhasthesamemeaning.Forexample:‘
1. ‘2015-02?-31’hasthesamemeaningas‘?2015-?02-31’.Inthiscase,thefirstformispreferredbecausetherearelessspecialcharacters.
2. 2015?-02-31hasthesamemeaningas?2015-02-31.Inthiscasethesecondformispreferred,becauseitmaysimplifyparsing.
3. 2015-02?-31’hasthesamemeaningas‘2015-?02?-31’.Inthiscase,thefirstformispreferredbecausethe‘?’in“?02”inthesecondformisredundant.
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4. 2015-02%-31?’hasthesamemeaningas‘2015-02~-31?’.Inthiscase,thefirstformispreferredbecauseitissimpler.
4.3 Unspecified
Thecharacter'X'maybeusedasareplacementcharacter,inplaceofadigittoindicatethatthevalueofthatdigitisunspecified.4.3.1 Level1
Thereplacementcharacter‘X’maybesubstitutedfortheright-mostdigitsinthefollowingcases:• Yearandmonthspecified,dayunspecified.• Yearspecified,dayandmonthunspecified.• Entiredateunspecified
Format:YYYY-MM-XXExample:1985-04-XXYYYY-XX-XXExample:1985-XX-XXXXXX-XX-XXExample:XXXX-XX-XX
RepresentationswithreducedaccuracyForrepresentationswithreducedaccuracy,‘X’maybeusedinthefollowingcases:
• Ayear-month,withmonthunspecified.• Ayear-month,withyearandmonthunspecified.• Ayearwithoneortwo(rightmost)unspecifieddigits.• Ayear,entireyearunspecified.
Format:YYYY-XXExample:2004-XXXXXX-XXExample:XXXX-XXYYYXExample:209XYYXXExample:20XXXXXXExample:XXXX
4.3.2 Level2
Forlevel2thecharacter‘X’maybeusedasareplacementforanycharacterinthestring.Examples156X-12-25December25sometimeduringthe1560s15XX-12-25December25sometimeduringthe1500s15XX-12-XXSomedayinDecemberinsomeyearduringthe1500s1560-XX-25The25thdayofsomemonthinyear1560.1560-X2ThemonthofeitherFebruaryorDecemberoftheyear1560.1XXX-XXSomemonthduringthe1000s1XXX-12SomeDecemberduringthe1000s1XXXSomeyearduringthe1000s1XX3Someyearendingin3duringthe1000s
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4.4 Beforeorafter
Adatemaybequalifiedtoindicate“beforeoron”or“onorafter”thedate.
4.4.1 Level1
Thisfeatureisnotusedinlevel1.
4.4.2 Level2
Forlevel2,thedotnotation“..”(twodots)maybeusedbeforeadatetodenote“beforeoronthedate”orafteradatetodenote“onthisdateorafter:
Examples
• ..1984beforeorduringtheyear1984• 1984..duringtheyear1984orlater• ..1984-04-04beforeoron4April1984
4.5 Enhancedtimeinterval
AnenhancedtimeintervalextendsthespecificationoftimeintervalinPart1ofthisstandard(startandenddateseparatedby‘/’)byindicatingthatthestartorenddateis:
• Unknown.Startorenddateunknown.Thecharacter‘*’(asterisk)maybeusedforthestartorenddatetoindicate“unknown”.
• OpenStartordateopen.Thestartorenddatemaybeleftblank,eitherbecausethereisnoneorforanyotherreason.
Thefollowingareallowedbutshouldbeusedonlywithcaution:• ‘*/*startandendbothunknown• ‘/’startandenddatebothopen• ‘*/’Startunknown,endopen• ‘/*’.Startopen,endunknown
4.5.1 Level1
format:YYYY-MM-DD/*Example:1985-04-12/**/YYYY-MM-DDExample:*/1985-04-12YYYY-MM-DD/Example:1985-04-12//YYYY-MM-DDExample:/1985-04-12Inadditionamodifiermayappearattheendofthedatetoindicate"uncertain"and/or"approximate"asdescribedin4.2.Examples:
• 1984-01-02~/2004-06-04beginningapproximately1984-01-02andending2004-06-04
• 1984-01-02~/beginningapproximately1984-01-02;noenddate
• 1984-01-02~/*beginningapproximately1984-01-02;enddateunknown
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• 1984~/2004-06beginningapproximately1984andendingJune2004
• 1984/2004-06~beginning1984andendingapproximatelyJune2004
• 1984?/2004%beginningisuncertainbutthoughttobe1984;endisuncertainbutthoughttobeapproximately2004
4.5.2 Level2
TheLevel2enhancedtimeintervalfeatureextendsLevel1:• Portionsofadatemaybedesignatedasapproximate,uncertain,orunspecified.• Thestartdatemaybetaggedas“beforeor”thatdate,andtheenddate“orafter”.
Examples:
• 2004-06-~01/2004-06-~20AtimeintervalinJune2004beginningapproximatelythefirstandendingapproximatelythe20th.
• 2004-06-XX/2004-07-03ThetimeintervalbeganonanunspecifieddayinJune2004andendedJuly3.
• ..2004-06-01/~2004-06-20Atimeintervalbeginningbeforeoron1June2004andendingapproximatelythe20th
• 2004-06-01~/2004-06-20..Atimeintervalbeginningbeforeapproximately1June2004andthe20thorlater.
4.6 Yearexceedingfourdigits
Part1ofthisstandardallowsayeartoexceedfourdigits(ayearafter9999orbefore-9999)howeveritrequiresmutualagreementofthepartnersintheinformationexchange.Presentedhereisanalternativemethod,whichdoesnotrequiremutualconsent.Itmaybeusedonlyfordateswhereonlytheyearissignificant,notthemonthorday.4.6.1 Level1
'Y’maybeusedatthebeginningofthedatestringtosignifythatthedateisayear,when(andonlywhen)theyearexceedsfourdigits,i.e.foryearslaterthan9999orearlierthan-9999.
Format:“Y”YYYYY…..Example:Y170000002(theyear170000002)“Y-”YYYYY…..Example:Y-170000002(theyear-170000002)4.6.2 Level2(needsreconsideration)
Level2presentsanalternative,exponentialform.'E'isusedtomean"times10tothepowerof"thus17E8means"17times(10totheeighthpower)",or170000000000.(Andasinlevel1.'Y'atthebeginningofthestringindicates"year”.)Examples
• y17E7theyear170000000
• y-17E7theyear-170000000
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4.7 Significantdigits
Whenayearisfollowedby‘S’,followedbyapositiveinteger,theintegerindicatesthenumberofsignificantdigitsfortheexpressedyear.4.7.1 Level1
Thisfeatureisnotusedinlevel1.
4.7.2 Level2
Forlevel2thisfeaturemaybeusedforanyofthefollowingthreewaystoexpressayear:• Four-digityear• Yearlongerthanfourdigitsexpressedasaninteger.• Yearexpressedinexponentialform.
Examples
• 1950S2Someyearbetween1900and1999,estimatedtobe1950.
• Y171010000S3Someyearbetween171000000and171999999,estimatedtobe171010000.
• Y17101E4S3Samemeaningaspreviousexample.
4.8 Divisionsofayear
Forayear-and-monthexpression(e.g.1984-04)themonthcomponentmaytakeonvaluesof21orabove(inplaceofamonthvalue,01through12).Thesevaluessignifyadivisionofayear(e.g.“theseasonSpring”).4.8.1 Level1
Thevalues21,22,23,24maybeusedtosignify'Spring','Summer','Autumn','Winter',respectively.Format:YYYY-SSExample:2001-21(Spring,2001)
4.8.2 Level2
Valuesgreaterthan24maybeused.Thisspecificationprovidesaninitialsetofvalues,andtherewillbearegistrationmechanismforadditionalvalues.Theinitialsetsofvaluesfortraditionaldivisionofayearare:21-24=Spring,Summer,Autumn,Winter,independentof“Hemisphere”25-28=Spring-NorthernHemisphere,Summer-NorthernHemisphere,Autumn-NorthernHemisphere,Winter-NorthernHemisphere29-32=Spring–SouthernHemisphere,Summer–SouthernHemisphere,Autumn–SouthernHemisphere,Winter-SouthernHemisphere33-36=Quarter1,Quarter2,Quarter3,Quarter4(3monthseach)37-39=Quadrimester1,Quadrimester2,Quadrimester3(4monthseach)
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40-41=Semestral1,Semestral-2(6monthseach)4.9 Oneofaset
Squarebracketsenclosingalistofdatesareusedtomean“oneofthesedates”.Thisfeaturemaybeusedforexampletoexpress“YearofPublication”,whenitisknownthattheyearisoneofasetofyears,forexample1984,1986,or1988.4.9.1 Level1
Thisfeatureisnotusedforlevel1.
4.9.2 Level2
Forlevel2double-dotnotationmaybeused.double-dotindicatesallthevaluesbetweenthetwovaluesitseparates,inclusive.Double-dotatthebeginningorendofthelistmeans"onorbefore"or"onorafter"respectively;seethesecond,third,andfourthexamplebelow.Differentelementsofalistmayhavedifferentprecisions,asinthefifthexample.Examples
• [1667,1668,1670..1672]Oneoftheyears1667,1668,1670,1671,1672
• [..1760-12-03]December3,1760;orsomeearlierdate
• [1760-12..]December1760,orsomelatermonth
• [1760-01,1760-02,1760-12..]JanuaryorFebruaryof1760orDecember1760orsomelatermonth
• [1667,1760-12]Eithertheyear1667orthemonthDecemberof1760.
4.10 Multipledates
Curlybracesmaybeusedtowrapaninclusivelist(allmembersincluded).Forexample{1960,1961,1962,1963}mightbeusedtoindicatetheyearsofpublicationofabook-itwaspublishedineachof1960,1961,1962,and1963.Differentelementsofalistmayhavedifferentprecisions,asinthesecondexample.4.10.1 Level1
Thisfeatureisnotusedinlevel1.
4.10.2 Level2
Examples• {1667,1668,1670..1672}
Alloftheyears1667,1668,1670,1671,1672• {1960,1961-12}
Theyear1960andthemonthDecemberof1961.
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4.11 Decade
Astringconsistingofthreedigitsrepresentsadecade,forexample“the1960s”.Itistheten-yeartimeintervalofthoseyearswherethethreespecifieddigitsarethefirstthreedigitsoftheyear.Representationofadecademustbeexactlythreedigits,leadingzeros,ifany,mustbeincluded.Thusthetimeinterval200through209isrepresentedas‘020’andNOT‘20’;thelatterwouldrepresentthetimeinterval2000through2099.Furthermore,‘196’isnottobeconfusedwiththeyear196,thatwouldberepresentedas‘0196’.4.11.1 Level1
Thisfeatureisnotusedforlevel1.
4.11.2 Level2
Format:YYYExample:196(1960-1969)Example:196~(approximatedecade)Note:asadecadeexpressesdecadeprecision,inthesecondexample,“approximatedecade”meansforexample“thedecadeisapproximatedtobethe1960s,butitmightbethe1950sor1970s.”ItdoesNOTmeanthetimeintervalbeginningapproximatelyatthebeginningofandendingapproximatelyattheendofthe1960s.Thelatterwouldbeexpressedas1960~/1970~andwouldhaveyearprecision.
5 Repeatrulesforrecurringtimeintervals
ThissectionextendsISO8601-1:2016,4.5“RecurringTimeInterval”,byaddingarulepartthatdefinestherepeatpatterntotheendoftherecurringtimeintervalstructure.
Allfeaturesinthissectionaredefinedatlevel1forthepurposeofprofiles,whichmayrefertothelevelswhenspecifyingconformancetotheprofile.(ProfilesaredescribedinAnnexB.)
The section is based on the [RFC 5545:2009] “Internet Calendaring and Scheduling Core ObjectSpecification (iCalendar), Section 3.3.10, Recurrence Rule” to ensure easy migration and transitionbetweenthetwostandards.
5.1 Meansofspecifyingrepeatrules
Repeatrulesforrecurringtimeintervalsshallbeexpressedinoneofthefollowingways.
a) Byanumberofrecurrences(optional),astartandendofthetimeinterval,andrepeatrule.Ifthenumberofrecurrencesisabsent,thenumberofoccurrencesisunbounded.
b) Byanumberofrecurrences(optional),adurationandrepeatrule.Ifthenumberofrecurrencesisabsent,thenumberofoccurrencesisunbounded.
c) Byanumberofrecurrences(optional),astartanddurationofthetimeinterval,andrepeatrule.Ifthenumberofrecurrencesisabsent,thenumberofoccurrencesisunbounded.
d) Byanumberofrecurrences(optional),adurationandendofthetimeinterval,andrepeatrule.Ifthenumberofrecurrencesisabsent,thenumberofoccurrencesisunbounded.
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5.2 Separatorsanddesignators
Repeatrulesforarecurringtimeintervalisexpressedaccordingtothefollowingstructure.
Allrepresentationsstartwiththedesignator[R],followed,withoutspaces,bythenumberofrecurrences,ifpresent,followed,withoutspaces,byasolidus[/],followed,withoutspaces,bytheexpressionofatimeintervalasperISO8601-1:2016,4.4.1,withoutspaces,byasolidus[/],followed,withoutspaces,followedbytherepeatruleasper5.3.Fortherepresentations5.1a),5.1b),5.1c)and5.1d)thetimeintervalsasperISO8601-1:2016,4.4.1a),4.4.1b),4.4.1c)and4.4.1d)shallbeused,respectively.
5.3 Repeatrules
Arepeatrule[RRULE]shallbeexpressedasastructuredcomponentconsistingofalistofoneormorerepeatruleparts.Eachrulepartisdefinedbyaname=valuepair.Therulepartsareseparatedfromeachotherbythesemicolon[;]character.Therulepartsarenotorderedinanyparticularsequence.Individualrulepartsmustonlybespecifiedonce.
5.4 Frequencyrulepart
The“Frequency”[FREQ]rulepartidentifiesthetypeofrecurrencerule.ThisrulepartMUSTbespecifiedintherepeatruleunlessthe“Divisional”[DIVI]ispresent,onlyoneofthetwocanbeused.ValidvaluesincludeSECONDLY[SE],tospecifyrecurringtimeintervalsbasedonatimeintervalofasecondormore;MINUTELY[MI],tospecifyrecurringtimeintervalsbasedonatimeintervalofaminuteormore;HOURLY[HR],tospecifyrecurringtimeintervalsbasedonatimeintervalofanhourormore;DAILY[DY],tospecifyrecurringtimeintervalsbasedonatimeintervalofadayormore;WEEKLY[WE],tospecifyrecurringtimeintervalsbasedonatimeintervalofaweekormore;MONTHLY[MO],tospecifyrecurringtimeintervalsbasedonatimeintervalofamonthormore;andYEARLY[YR],tospecifyrecurringtimeintervalsbasedonatimeintervalofayearormore.
5.5 Divisionalrulepart
The“Divisional”[DIVI]rulepartidentifiesthetypeofrecurrencerule.ThisrulepartMUSTbespecifiedin the repeat rule unless the “Frequency” [FREQ] is present, only one of the two can be used. Valid“Divisionofayear”valuesaredefinedinsection4.8.2.
5.6 Timeintervalrulepart
The“Timeinterval”[INTR]rulepartcontainsapositiveintegerrepresentingatwhichtimeintervalsthe“Frequency”or“Divisional”rulepartrepeats.Thedefaultvalueruleis"1",meaningeverysecondforaSECONDLYrule,everyminuteforaMINUTELYrule,everyhourforanHOURLYrule,everydayforaDAILYrule,everyweekforaWEEKLYrule,everymonthforaMONTHLYrule,everyyearforaYEARLYrule,andasinglerepeatforeachDIVISIONALrule.
Forexample,usedwiththeFREQUENCYrulevalueofDAILYrule,avalueof"8"meanseveryeightdays:
FREQ=DA;INTR=8
UsedwithaDIVISIONALrulevalueofSUMMER,avalueof“2”meanseverysecondsummer:
DIVI=22;INTR=2
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5.7 Byruleparts
“Byruleparts”[BYXX]modifiestherepeatsinsomemanner.Byrulepartsforatimeintervalofthesamelengthorlongerthanthefrequencygenerallyreducesorlimitsthenumberofoccurrencesoftherepeatsgenerated.
Example:
FREQ=DA;BYMO=1reducesthenumberofrepeatinstancesfromalldays(ifByMonthrulepartisnotpresent)toalldaysinJanuary.
Byrulepartsforatimeintervalshorterthanthefrequencygenerallyincreasesorexpandsthenumberofoccurrencesoftherepeats.
Example:
FREQ=YE;BYMO=1,2increasesthenumberofdayswithintheyearlyrepeatsetfrom1(ifByMonthrulepartisnotpresent)to2.
5.7.1 Bysecondrulepart
The“BySecond”[BYSE]rulepartspecifiesacomma-separatedlistofsecondswithinaminute.Validvaluesare0to59.
5.7.2 Byminuterulepart
The“ByMinute”[BYMI]rulepartspecifiesacomma-separatedlistofminuteswithinanhour.Validvaluesare0to59.
5.7.3 Byhourrulepart
The“ByHour”[BYHR]rulepartspecifiesacomma-separatedlistofhoursoftheday.Validvaluesare0to23.
5.7.4 Bydayrulepart
The“ByDay”[BYDY]rulepartspecifiesacomma-separatedlistofdaysoftheweek;MOindicatesMonday;TUindicatesTuesday;WEindicatesWednesday;THindicatesThursday;FRindicatesFriday;SAindicatesSaturday;andSUindicatesSunday.
EachByDayvaluecanalsobeprecededbyapositive(+n)ornegative(-n)integer.Ifpresent,thisindicatesthenthoccurrenceofaspecificdaywithintheMONTHLYorYEARLY"RRULE".
Forexample,withinaMONTHLYrule,+1MO(orsimply1MO)representsthefirstMondaywithinthemonth,whereas-1MOrepresentsthelastMondayofthemonth.ThenumericvalueinaByDayrulepartwiththeFREQrulepartsettoYEARLYcorrespondstoanoffsetwithinthemonthwhentheByMonthrulepartispresent,andcorrespondstoanoffsetwithintheyearwhentheByWeekNoorByMonthrulepartsarepresent.Ifanintegermodifierisnotpresent,itmeansalldaysofthistypewithinthespecifiedfrequency.Forexample,withinaMONTHLYrule,MOrepresentsallMondayswithinthemonth.TheByDayrulepartMUSTNOTbespecifiedwithanumericvaluewhentheFREQrulepartisnotsettoMONTHLYorYEARLY.Furthermore,theByDayrulepartMUSTNOTbespecifiedwithanumericvaluewiththeFREQrulepartsettoYEARLYwhentheByWeekNorulepartisspecified.
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5.7.5 Bymonthdayrulepart
The“ByMonthDay”[BYMD]rulepartspecifiesacomma-separatedlistofdaysofthemonth.Validvaluesare1to31or-31to-1.Forexample,-10representsthetenthtothelastdayofthemonth.TheByMonthDayrulepartMUSTNOTbespecifiedwhentheFREQrulepartissettoWEEKLY.
5.7.6 Byyeardayrulepart
The“ByYearDay”[BYYD]rulepartspecifiesacomma-separatedlistofdaysoftheyear.Validvaluesare1to366or-366to-1.Forexample,-1representsthelastdayoftheyear(December31st)and-306representsthe306thtothelastdayoftheyear(March1st).TheByYearDayrulepartMUSTNOTbespecifiedwhentheFREQrulepartissettoDAILY,WEEKLY,orMONTHLY.
5.7.7 Byweeknorulepart
The“ByWeekNo”[BYWN]rulepartspecifiesacomma-separatedlistofordinalsspecifyingweeksoftheyear.Validvaluesare1to53or-53to-1.ThiscorrespondstoweeksaccordingtoweeknumberingasdefinedinISO8601-1:2016.Aweekisdefinedasaseven-daytimeinterval,startingwithaMonday.Weeknumberoneofthecalendaryearisthefirstweekthatcontainsatleastfour(4)daysinthatcalendaryear.ThisrulepartMUSTNOTbeusedwhentheFREQrulepartissettoanythingotherthanYEARLY.Forexample,3representsthethirdweekoftheyear.
Note:Week53canonlyoccurwhenThursdayisJanuary1orifitisaleapyearandWednesdayisJanuary1.
5.7.8 Bymonthrulepart
The“ByMonth”[BYMO]rulepartspecifiesacomma-separatedlistofmonthsoftheyear.Validvaluesare1to12.
5.7.9 Multiple“Byrule”parts
IfmultipleByrulepartsarespecified,thenafterevaluatingthespecifiedFrequencyandTimeintervalruleparts,theByrulepartsareappliedtothecurrentsetofevaluatedoccurrencesinthefollowingorder:ByMonth,ByWeekNo,ByYearDay,ByMonthDay,ByDay,ByHour,ByMinuteandBySecond;thennumberofrecurrencesanddurationareevaluated.
5.7.10 ExampleofevaluatingmultipleByxxxruleparts
R/20150104T083000/PM15S00/FREQ=YR;INTR=2;BYMO=1;BYDA=SU;BYHO=8,9;BYMIN=30
First,the"INTR=2"wouldbeappliedto"FREQ=YR"andbeevaluatedas"everyotheryear".Then,"BYMO=1"wouldbeevaluatedas"everyJanuary,everyotheryear".Then,"BYDA=SU"wouldbeevaluatedas"everySundayinJanuary,everyotheryear".Then,"BYHO=8,9"wouldbeevaluatedas"everySundayinJanuaryat8AMand9AM,everyotheryear".Then,"BYMI=30"wouldbeevaluatedas"everySundayinJanuaryat8:30AMand9:30AM,everyotheryear".Then,lackinginformationfrom"RRULE",thesecondisderivedfrom"TimeintervalStart"value,toendupin"everySundayinJanuaryat8:30:00AMand9:30:00AM,everyotheryear".Similarly,iftheByMinute,ByHour,ByDay,ByMonthDay,orByMonthrulepartismissing,theappropriateminute,hour,day,ormonthwillberetrievedfromthe"TimeintervalStart"value.Finally,thetimeintervaldurationisdefinedbythe“Duration”value,whichinthiscaseis15minutes.
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5.8 Completerepresentations
Whentheapplicationidentifiestheneedforacompleterepresentationofarecurringtimeintervalwithrepeatrules,itshalluseanexpressioninaccordancewith5.2,combininganycompleterecurringtimeintervalrepresentationasdefinedinISO8601-1:2016,4.5.3withtherepeatrule.
Basicformat: Rn/YYYYMMDDThhmmss/YYYYMMDDThhmmss/FREQ=value;INTR=n Rn/YYYYMMDDThhmmss/PnnYnnMnnDTnnHnnMnnS/FREQ=value;INTR=n RnPnnYnnMnnDTnnHnnMnnS/YYYYMMDDThhmmss/FREQ=value;INTR=n Rn/PnnYnnMnnDTnnHnnMnnS/FREQ=value;INTR=n
Example: R12/20150929T140000/20150929T153000/FREQ=WE;INTR=2 R12/20150929T140000/P1H30M0S/FREQ=WE;INTR=2 R12/P2H30M0S/20150929T153000/FREQ=WE;INTR=2 R12/P2Y10M15DT10H30M20S/FREQ=WE;INTR=2
Extendedformat:Rn/YYYY-MM-DDThh:mm:ss/YYYY-MM-DDThh:mm:ss/FREQ=value;INTR=n Rn/YYYY-MM-DDThh:mm:ss/PnYnMnDTnHnMnS/FREQ=value;INTR=n Rn/PnnYnnMnnDTnnHnnMnnS/YYYY-MM-DDThh:mm:ss/FREQ=value;INTR=n
Example: R12/2015-09-29T14:00:00/2015-09-29T15:30:00/FREQ=WE;IINTR=2 R12/2015-09-29T14:00:00/P1H30M0S/FREQ=WE;INTR=2 R12/P1H30M0S/2015-09-29T15:30:00/FREQ=WE;INTR=2
5.9 Representationsotherthancomplete
Arepresentationotherthancompleteofarecurringtimeintervalwithrepeatruleshallbeanexpressioninaccordancewith5.1and5.2,wherethetimeintervalisrepresentedinaccordancewithISO8601-1:2016,4.4.5.
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AnnexA(normative)
EBNFnotation
The syntax used in this EBNF description is ISO/IEC 14977:1996 Rule: name = ... ; Terminal: '...' or "..." Non Terminal: ... Concatination: , Choice: | Optional: [...] Repetition (0 or more): {...} Repetition (1 or more): {...}- Repetition (n times): n * ... Grouping: (...) Exception: ...-... Special sequence: ?...? Comment: (*...*) (* Base definitions *) year = positiveYear | negativeYear | "0000" ; positiveYear = positiveDigit, digit, digit, digit | "0", positiveDigit, digit, digit | "00", positiveDigit, digit | "000", positiveDigit ; negativeYear = "-", positiveYear ; monthDay = ("01" | "03" | "05" |"07" |"08" |"10" |"12"), "-", OneThru31 | ("04" | "06" | "09" | "11"), "-", OneThru30 | "02-", OneThru29 ; yearMonth = year "-" month ; month = oneThru12 ; day = oneThru31 ; date = year | yearMonth | yearMonthDay ; oneThru12 = ("0", positiveDigit) | "10" | "11" | 12" ; oneThru29 = ("0", positiveDigit) | (("1" | "2"), digit) ; oneThru30 = OneThru29 | "30" ; oneThru31 = OneThru30 | "31" ; digit = positiveDigit | "0" ; positiveDigit = "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" ;
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(* 4. Date and Time Extensions *) (* 4.1.1 Extended Format *) yearMonthDay = year, "-", monthDay ; (* 4.1.1 Levels *) (* For the extension features, two levels are defined: level 1 *) (* and level 2. Each major subsection of section 4 covers a *) (* general feature; some functions covered by that feature are *) (* level 1 and some are level 2. These levels are defined for *) (* the purpose of profiles, which may refer to the levels when *) (* specifying conformance to the profile. *) (* 4.2.1 Level 1 - Uncertain and/or Approximate Date *) uaDate = yearMonthDay, uaSymbol ; uaSymbol = "?" | "~" | "%" ; (* Reduced accuracy *) reducedDate = (year | yearMonth), uaSymbol ; (* 4.2.2 Level 2 - Uncertain and/or Approximate Date *) qualifiedDate = [uaSymbol], year, [uaSymbol], "-", [uaSymbol], month, [uaSymbol], "-", [uaSymbol], day, [uaSymbol] ; (* 4.3.1 Level 1 - Unspecified Date *) unspecifiedDate = (yearMonth, "-XX") | (year, "-XX-XX") | "XXXX-XX-XX" ; (* Reduced accuracy *) reduceAccuracyDate = (2 * digit, "XX") | (3 * digit, "X") | ("XXXX", ["-XX"]) | (year, "-XX") ; (* 4.3.2 Level 2 - Unspecified Date *) replacementDate = 4 * (digit | "X"), ["-", 2 * (digit | "X"), ["-", 2 * (digit | "X")]] ; (* 4.4.1 Level 1 - Before or After *) (* This feature is not used in level 1. *) (* 4.4.2 Level 2 - Before or After *) beforeAfterDate = ("..", year, ["-", month, ["-", day]]) | (year, ["-", month, ["-", day]], "..") ; (* 4.5.1 Level 1 - Enhanced Interval *)
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startEndOpenOrUnknown = [yearMonthDay],["*"],"/",["*"],[yearMonthDay] ; L1Interval = [year | yearMonth | yearMonthDay], [uaSymbol | "*"], "/", ["*"], [year | yearMonth | yearMonthDay], [uaSymbol] ; (* 4.5.2 Level 2 - Enhanced Interval *) L2Interval = [".."], (qualifiedDate | unspecifiedDate | replacementDate), "/", (qualifiedDate | unspecifiedDate | replacementDate ), [..] ; (* 4.6.1 Level 1 - Year Exceeding Four Digits *) longYear = "Y", ["-"], positiveDigit 4 * digit, {digit} ; (* 4.6.2 Level 2 - Year Exceeding Four Digits *) longYearScientific = "y", ["-"], positiveDigit, digit, "e" {digit}- ; (* 4.7.1 Level 1 - Significant Digits *) (* This feature is not used in level 1. *) (* 4.7.2 Level 2 - Significant Digits *) yearDate = (year | longYear | longYearScientific), "S", positiveDigit, {digit} ; (* 4.8.1 Level 1 Divisions of a year *) divisionL1 = year, divisionSet1; divisionSet1 = ("21" | "22" | "23" | "24") ; (* 4.8.2 Level 2 Divisions of a year *) divisionL2 = year, divisionSet2 ; divisionSet2 = (("2" | "3"), digit) | "40" | "41" ; (* 4.9.1 Level 1 - One of a Set *) (* This feature is not used in level 1. *) (* 4.9.2 Level 2 - One of a Set *) choiceList = "[", listContent "]" ; listContent = earlier, {",", listElement} | [earlier, ","], {listElement, ","}, later | listElement {"," listElement}- | consecutives ; listElement = date | qualifiedDate | unspecifiedDate | consecutives ; earlier = "..", date ; later = date ".." ; consecutives = yearMonthDay, "..", yearMonthDay
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| yearMonth, "..", yearMonth | year, "..", year ; (* 4.10.1 Level 1 - Multiple Dates *) (* This feature is not used in level 1. *) (* 4.10.2 Level 2 - Multiple Dates *) inclusiveList = "{" listContent "}" ; (* 4.11.1 Level 1 - Decade *) (* This feature is not used in level 1. *) (* 4.11.2 Level 2 - Decade *) decade = 3 * digit, ["~"] ; (* 5. Repeat Rules for Recurring Time Intervals *) (* All features in this section are defined at level 1 for the *) (* purpose of profiles, which may refer to the levels when *) (* specifying conformance to the profile. *) recurringIntervalWithRules = recurringInterval, "/", recurringRule ; recurringInterval = 'R', {integer}, '/', interval ; interval = intervalExplicit | intervalStart | intervalEnd | duration ; intervalExplicit = dateAndTime, '/', dateAndTime ; intervalStart = dateAndTime, '/', duration ; intervalEnd = duration, '/', dateAndTime ; duration = 'P', (durationTime | durationDate | durationWeek) ; durationDate = durationDay, [durationTime] ; durationTime = 'T', (durationHour | durationMinute | durationSecond) ; durationHour = hour, 'H', [durationMinute] ; durationMinute = minute, 'M', [durationSecond] ; durationSecond = second, 'S' ; durationDay = day, 'D' ; durationWeek = week, 'W' ; recurringRule = recurringRulePart, {';', recurringRulePart} ; recurringRulePart = ( ('FREQ', '=', freqency) | ('DIVI', '=', division)) | ( 'INTR', '=', digit {digit} ) | ( 'BYSE', '=', second )
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| ( 'BYMI', '=', minute ) | ( 'BYHR', '=', hour ) | ( 'BYDY', '=', byWeekDayList ) | ( 'BYMD', '=', byMonthDayList ) | ( 'BYYD', '=', byYearDayList ) | ( 'BYWN', '=', byweekNumberberList ) | ( 'BYMO', '=', byMonthList ) ; freqency = 'SE' | 'MI' | 'HR' | 'DY' | 'WE' | 'MO' | 'YR' ; division = divisionSet2 ; (* see 4.8.2 *) byWeekDayList = weekDayNumber, {',', weekDayNumber} ; weekDayNumber = [weekByNumber], weekDay ; weekDay = 'SU' | 'MO' | 'TU' | 'WE' | 'TH' | 'FR' | 'SA' ; byMonthDayList = monthDayNumber, {',', monthDayNumber} ; monthDayNumber = ["+" | "-"], monthDay ; byYearDayList = yearDayNumber, {',', yearDayNumber} ; yearDayNumber = ["+" | "-"], yearDay ; byweekNumberList = weekNumber, {',', weekNumber} ; weekByNumber = ["+" | "-"], weekNumber ; byMonthList = monthNumber, {',', monthNumber} ;
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AnnexB(normative)
ISO8601profiles
B.1 Statementoftheproblem
ISO 8601 includesmany features, and, inmany cases, several different formats to represent a singlefeature. Two vendors implementing 8601 may implement different features, or differentrepresentationsofagivenfeature,andtheirproductsmightnotinteroperate.Moreover,somefeatureshavemorethanoneinterpretationanddifferentvendorsmightselectdifferentinterpretation,makinginteroperabilityevenlesslikely.8601doesnotprovideguidelinestoaddresstheseconcerns,levelsofsupport, or conformance requirements. Each vendor is left to decide for itself what features,representation,andinterpretationstoimplement.
B.1.1 Somehistoricalbackground
The W3C defined date and time formats to begin to address these concerns:http://www.w3.org/TR/xmlschema-2/#isoformats. These formatsarebasedon8601,and theyhaveprovedinvaluablefortheinteroperabilityofWebdata.Theseformatshavetheirrootsinwhatwecalla“profile”ofISO8601:DateandTimeFormats.http://www.w3.org/TR/NOTE-datetimewhichstates
“Thisdocumentdefinesaprofileof ISO8601, the InternationalStandard for the representationofdatesandtimes.ISO8601describesalargenumberofdate/timeformats.Toreducethescopeforerrorandthecomplexityofsoftware,itisusefultorestrictthesupportedformatstoasmallnumber.Thisprofiledefinesafewdate/timeformats,likelytosatisfymostrequirements.
TheW3CNote,submittedin1997byReuters,wasneverendorsedbytheW3C,but itdidprovidetheoriginalimpetusforthedevelopmentoftheveryusefulandsuccessfulW3Cdateandtimeformats.
B.1.2 GeneralizingtheconceptofanISO8601profile
ThisdocumentattemptstoexpandandgeneralizetheconceptofanISO8601Profile.
AProfileof ISO8601 isa specificationdevelopedbyaparticularcommunitywhichexplainshowISO8601istobeused,tocarryoutaparticularfunctionorgroupoffunctionsrelevanttothatcommunity.
1. Itmaylistfeaturesof8601tobesupported.
2. In caseswhere therearemultiplemethods specified in8601 to supportaparticular function,theprofilemayselectasinglemethod.
3. Incaseswheretherearedifferentinterpretationsofaparticularfunction,theprofilemayselectasingleinterpretation,orprovideclarification.
4. Itmightlistfeaturesthatarenotrelevantandneednotbesupported.
5. Itmightspecifyseverallevelsofsupport.
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At minimum, a profile should state what an implementer must implement in order to claimconformance to the profile. If there are multiple levels specified, it should state conformancerequirementsforeachlevel.
Differentcommunitiesmaydefinedifferentprofiles.Infactanygivencommunitymaydefinemultipleprofiles. “Community” is used loosely tomean a groupwith a common interest in 8601. It is notintendedthat8601profilesbeapprovedbyanyformalbody;anypersonorcommunitycandevelopaprofile. There shouldhoweverbe auniquename for everyprofile so that itmaybe referenced. TheregistrationagencyforISO8601shouldregisterprofilesuponrequest,andhelptoassureuniquenessofnames. It is hoped that there will be mechanisms developed to provide interoperability betweenprofileshoweverthatisbeyondthescopeofthisdocument.
Thisdocumentprovidesone(draft)profile(section2),anditisexpectedthatadditionalprofileswillbedeveloped.
B.1.3 Multipleprofiles
Aproductmay implement several profiles.Herewe distinguish between static support and dynamicoperation.
B.1.3.1 StaticSupport
SupposeprofileXspecifiesfeaturesA,B,andC,andexcludesfeatureD.IfaproductclaimstosupportprofileX thatdoesnotmean that it cannot support featureD. Adifferentprofile –profileY –mightspecify features C, D, and E. And there is not, nor should there be, anything inherent in the profileconceptthatwouldprecludeaproductfromsupportingasmanyprofilesasitchoosestosupport.
B.1.3.2 DynamicOperation
Ontheotherhandsupposetherearetwocommunicationparties,P1andP2,exchangingISO8601data.P1usesaproductthatsupportsprofileX(only)whileP2usesaproductthatsupportsprofilesXandY.InorderforP1andP2tointeroperatetheymustoperateunderprofileX,becauseitistheonlyprofileincommonsupported.(ThusP2mustbeabletosuppressfeaturesexcludedbyP1.)
Theprocessbywhichtwocommunicatingpartiesagreetooperateaccordingtoaparticularprofileisacomplexareawhichneedsfurtherstudy.It isnotfullyaddressedbythisdocumentandistoacertainextendoutsidethescopeofthisdocument.Threepossibleapproaches:
1) SpecifiedbyProtocol.Theexchangeof ISO8601datamightbedoneunder thecontrolofaprotocol,whichcouldbeusedtonegotiateaparticularprofile.(8601itselfisadataformat,notaprotocol,andcouldnotbeadaptedtoaccomplishthistask.)
2) Specified by Format.Two parties might be exchanging data of a certain type, for examplebibliographicdata.Thedefinitionofthebibliographicformatcouldspecifythatdate/timedataconformtoaspecificprofile.
3) Specified by datatype. For exchange of date serialized into XML, or RDF (any RDFserialization),dateand timedatacancarry itsdatatype, forexamplexs:date,which,asnotedabove,correspondstotheW3Cprofile.
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AnnexC(informative)
TheExtendedDate/TimeFormat-AProfileofISO8601(Parts1and2)
C.1 Introduction
The Extended Date/Time Format (EDTF) profile of ISO 8601 was developed by the bibliographiccommunityalongwiththeparticipationofcommunitieswithrelatedinterests.
Thisprofilespecifiesthreelevels:level0,level1,andlevel2.Level0specifiesfeaturesofISO8601Part1.Levels1and2specifyfeaturesofPart2/level1andPart2/level2respectively.
C.1.1 Compliance
An implementation of this specification must support all of the features listed for Level 0, and thevendorshouldstateoneofthefollowing:
• Level0(only)issupported.• Level0issupportedandinadditionthefollowingfeaturesoflevels1and2aresupported(list
features).• Level1issupported.• Level 1 is supported and in addition the following features of level 2 are supported (list
features).• Level2issupported.
Twocommunicationpartiesthatagreetooperateaccordingtothisprofilemustsuppress,duringtheircommunication,anyISO8601featuresthatarenotincludedinlevel0.
C.1.2 Extendedformat
All features in this profile use extended format: hyphens separating date components and colonsseparatingtimecomponents.Basicformatisnotused.
C.1.3 Level0
Inorder to claimsupport for level0of thisprofile, an implementationmust supportdate (yearonly,year andmonth, andyear,month andday), date and time, time interval, and century, as specified in2.3.1-2.3.3
C.1.3.1 Date
Adatestringrepresentsoneofthefollowing:
• year,month,andday(e.g.2001-02-03)• yearandmonth(e.g.2008-12)• year(e.g.2008)
Yearmustbefourdigits.(Yearslongerthanfourdigitsarecoveredinlevels1and2.)
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A yearmay be positive, negative, or year zero. (This specification assumes astronomical numbering,whichincludestheyearzero.)
C.1.3.2 DateandTime
Adate/timestringiscomposedaccordingtooneofthreerepresentationsasillustratedinthefollowingthreeexamples:
• 2001-02-03T09:30:01• 2004-01-01T10:10:10Z• 2004-01-01T10:10:10+05:00
Zone-offsetmaybeomittedorincluded.Timezonedesignationconsistsofeithera'Z'toindicateUTC,ora'+'or'-'toindicate"aheadofUTC"or"behindUTC",followedbya2-digithour,followedoptionallybyacolonandthe2-digitminutes.
C.1.3.3 Timeinterval
Atimeinterval,asrepresentedbyastartdateandanenddate(separatedbyaforwardslash),isatimeintervalbeginningsometimeduringthestartdateandendingsometimeduringtheenddate.Theactualinstantsatwhichthetime intervalbeginsorendscanbenarroweddownonlytotheprecisionof thestartorenddate.Thestartandenddatesarebothasprescribedin2.3.1.Eitherendpointmaybeayear,year-month,oryear-month-day.Theendendpointmustbelaterthanorequaltothestartendpoint.
Examples
• 1964/2008Atimeintervalwithyearprecision,beginningsometimein1964andendingsometimein2008.
• 2004-06/2006-08A time intervalwithmonthprecision,beginning sometime in June2004andending sometime inAugustof2006.
• 2004-02-01/2005-02-08Atimeintervalwithdayprecision,beginningsometimeonFebruary1,2004andendingsometimeonFebruary8,2005.
• 2004-02-01/2005-02AtimeintervalbeginningsometimeonFebruary1,2004andendingsometimeinFebruary2005.Note that the start endpoint has different precision than the end endpoint (day/month) andthereforetheprecisionofthetimeintervalatlargeisundefined.
• 2004-02-01/2005AtimeintervalbeginningsometimeonFebruary1,2004andendingsometimein2005.Thestartendpoint has day precision and the end endpoint has year precision. Similar to the previousexample,theprecisionofthetimeintervalatlargeisundefined.
• 2005/2006-02Atimeintervalbeginningsometimein2005andendingsometimeinFebruary2006.
Atimeintervalrepresentsoneofthefollowing,dependingontheapplication:
a) Theperiodoftimerepresentedbythetimeinterval;b) Aspecificdateduringthattimeinterval,whenaneventoccurred.
Soforexample,thetimeinterval‘1956/1967’,dependingontheapplication,meanseither
a) Thetimeintervalbeginningsometimein1956andendingsometimein1967;or
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b) Theeventinquestionoccurredduringoneoftheyears1956,1957,….,1967
andinthiscase,hasyearprecision.
Inasimilarsense, thetime interval ‘1956-01/1967-06’ hasmonthprecision,and ‘1956-01-15/1967-06-20’hasdayprecision.
C.1.3.4 Century
Twodigitsmaybeusedto indicatethecenturywhichisthehundredyeartimeinterval consistingofyearsbeginningwiththosetwodigits.
Forexample‘19’maybeusedtoindicatethetimeintervalrepresentedby‘1900/1999’.
Note:Forpurposesofthisprofile,a“century”isa100-yeartimeinterval.Forexample,‘1866/1965’isacentury.‘1900/1999’and‘1901/2000’arealsocenturies,andalthoughthelatterissometimesreferredtoasthe“18thcentury”,thisspecificationDOESNOTaddressnamedcenturiessuchasthe“18thcentury”nordoesittakeapositiononthemeaningofanamedcentury. Theprofileaddressescenturiesoftheformnn00/nn99only,where‘nn’isanytwo–digitnumber,forexample‘1900/1999’.
C.1.4 Level1
Level1ofthisprofilerequiressupportfor:
• Level0,and• allofthefeaturesofLevel1ofISO8601Part2,withtheexceptionofrecurringtimeintervals
(section5).
C.1.5 Level2
Level2ofthisprofilerequiressupportfor:
• Level1,(withtheexceptionofrecurringtimeintervals,section5)and• allofthefeaturesofLevel2ofISO8601Part2.
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Bibliography
[1] ISO80000-1:2009,Quantitiesandunits--Part1:General
[2] ISO80000-3:2006,Quantitiesandunits--Part3:Spaceandtime
[3] ISO/IEC646:1991,Informationtechnology—ISO7-bitcodedcharactersetforinformationinterchange
[4] ISO19018:2004,Shipsandmarinetechnology—Terms,abbreviations,graphicalsymbolsandconceptsonnavigation
[5] IEC60050-112:2010,InternationalElectrotechnicalVocabulary—Part112:Quantitiesandunits
[6] IEC60050-113:2011,InternationalElectrotechnicalVocabulary—Part113:Physicsforelectrotechnology
[7] IEC60050-114:2011,InternationalElectrotechnicalVocabulary—Part114:Electrochemistry
[8] IEC60050-713:1998,InternationalElectrotechnicalVocabulary—Part713:Radiocommunications:transmitters,receivers,networksandoperation
[9] Rec.ITU-RTF.460-6(2002-02),Standard-frequencyandtime-signalemissions
[10] ITU-TRecommendationS.1(1993),InternationalTelegraphAlphabetNo.2