4.5.3 Complete representations (recurring time intervals)
When the application identifies the need for a complete representation of a recurring time interval, it shall use an expression in accordance with 4.5.2, combining any complete time interval representation as defined in 4.4.4 with the number of recurrences.
At first, I thought it was going to be something that would allow one to express, e.g. I start work from this date, from this hour to this hour, these days of the week.
But the format seems to only express contiguous intervals. What's the point of recurring intervals if they're limited to be contiguous? You could just join them into one interval.
EDIT: Or am I wrongly assuming that they're contiguous and rather they just don't specify when they repeat?
It's probably more useful to think of recurring intervals as specifying an instant plus a period until the recurring instant. Cron jobs, for example, use such a concept. If you want to specify how long some event starting at that instant should be, you can use a separate non-recurring interval to show that. In this frame, "how often should we start the budget meeting" and "how long should the budget meeting be" are separate questions and not discoverable with a single answer.
It seems obvious now that you've clarified it. :P Thanks. Though the name is a bit misleading. Maybe it should be called "recurring instants" instead.
I can now agree that it seems to be nicely thought out, flexible without being overly complicated. However, just like how the duration of the event can be a separate question, so too can the duration between instants and the number of repeats. I think this would be the main reason why it's not widely adopted. There just doesn't seem to be much of a need for a standard representation of durations or recurring intervals/instants.
From ISO 8601 Third edition 2004-12-01
---8<----
The following are examples of complete representations of date and time of day representations:
Basic format:
Example: Extended format: YYYY-MM-DDThh:mm:ss Example: 1985-04-12T10:15:30 ---8<----4.5.3 Complete representations (recurring time intervals)
When the application identifies the need for a complete representation of a recurring time interval, it shall use an expression in accordance with 4.5.2, combining any complete time interval representation as defined in 4.4.4 with the number of recurrences.
Basic format:
Example: Extended format: Example: