ISO8601 ANTLR4

iso8601.g4

dateFullyear : Digit{4};
dateMonth : Digit{2};
dateMday  : Digit{2};
timeHour  : Digit{2};
timeMinute : Digit{2};
timeSecond: Digit{2};
timeSecfrac : '.' Digit{1,};
timeNumOffset : ('+' | '-') timeHour ':' timeMinute;
timeOffset: 'Z' | timeNumOffset;
partialTime : timeHour ':' timeMinute ':' timeSecond timeSecfrac?;
fullDate : dateFullyear '-' dateMonth '-' dateMday;
fullTime : partialTime timeOffset;

dateTime
        : fullDate 'T' fullTime;