ISO 8601
ISO 8601:2004 is a standard having the name "Data elements and interchange formats — Information interchange — Representation of dates and times". [1]
tango.info uses the international date and time format as defined by w:ISO 8601. This eliminates ambiguities, makes searching the site and sorting dates easier.
Date
A standard date format looks like: 2006-05-01
Examples for non standard local formats:
- 01/05/06 (does it mean 2001-05-06 or 2006-01-05 or 2006-05-01?)
- 1.5.06
- 1/5/2006
- 5/1/2006
- 1.5.2006
Time
Time is always written like 21:30. Time intervals should be represented like 21:30--23:45.
Intervals
Intervals are represented by start point and end point, seperated by "--". The ISO standard recomends "/" but allows "--" as a seperator. Because "--" can be used in filenames, tango.info prefers this.
Examples for date intervals
- 2007-06-25--26 -> start: 2007-06-25 end 2007-06-26 (two days)
- 2007-06-25--29 -> start: 2007-06-25 end: 2007-06-29 (five days)
- 2007-06-25--07-01 -> start: 2007-06-25 end: 2007-07-01 (seven days, touching two monthes)
- 2007-12-30--2008-01-02 -> start: 2007-12-30 end: 2008-01-02 (four days, touching two monthes and two years.)
Examples for time intervals
Time intervals should be represented like 21:30--23:45.
Examples for datetime intervals
Datetime interval could be written like: 2008-09-26 20:00--22:00
Repeating intervals
- http://en.wikipedia.org/wiki/ISO_8601#Repeating_intervals
- defined in the standard in section 4.5 Recurring time interval
- Number of repetitions (optional) from 1 to unbounded
- plus one of the following
- a) start point and end point
- b) duration and context
- c) start point and duration
- d) duration and end point
- tango.info would use c). Example with unbounded repetition:
- R--2008-01-01T14:30--16:00
- how to define when an event is repeated?