org-timer-start at specified time stamp

["Florian Lindner" <mailinglists@xgm.de>]

Hello,

frequently, when taking notes at a meeting with org-timer active, I happened to forget to start the timer at the beginning of the meeting:

* Meeting
Start: <2021-07-30 Fri 15:37>

- 0:00:05 :: started the timer to late
- 0:00:18 :: want to set zero to the time above 15:37
- 0:00:34 :: how do so?

The documentation of org-timer-start says:

> Set the starting time for the relative timer to now.
> When called with prefix argument OFFSET, prompt the user for an offset time,
> with the default taken from a timer stamp at point, if any.
> If OFFSET is a string or an integer, it is directly taken to be the offset
> without user interaction.

This is about a timer stamp, not a timestamp.  Of course, it's possible, but to get the offset, I need to compute the amount of time from timer start to meeting start.

> When called with a double prefix arg, all timer strings in the active
> region will be shifted by a specific amount.  You will be prompted for
> the amount, with the default to make the first timer string in
> the region 0:00:00.

My proposal is to enhance C-u org-timer-start to also determine if it is located at a timestamp and use that as zero time.

Furthermore C-u C-u org-timer-start also can accept a timestamp and shift the region as if the timer was started at that time.

All that requires to distinguish between a timestamp and a timestamp. For the first part, it is possible, as the timestamp includes a date, for the second part it's more hairy, as 15:37 could be a shift by 15m and 37s or the timestamp of 15:37 (3:37 pm).

Alternatively, a new function can be introduced that manipulated the the running timer accordingly.

What do you think about that proposal? I am happy to work on that myself, but probably need some assistance from you!

Best, Florian