ISO 8601

tango.info uses the international date and time format a 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 from 1 to unbounded
  • a) start point and end point
  • b) duration and context
  • c) start point and duration
  • d) duration and end point
• use c) with unbounded repetition
  • R--2008-01-01T14:30--16:00
  • how to define when an event is repeated?

Links

• http://isotc.iso.org/livelink/livelink/4021199/ISO_8601_2004_E.zip?func=doc.Fetch&nodeid=4021199
• http://www.cl.cam.ac.uk/~mgk25/iso-time.html
• http://www.cs.tut.fi/~jkorpela/iso8601.html
• http://www.w3.org/TR/NOTE-datetime