[Remind-Fans] Periodic Reminders Using Omits

[Paul Pelzl]

On Mon, Mar 20, 2006 at 08:30:14AM -0500, Jason Stein wrote:
> Our school uses a 6 day repeating schedule. I would like to create a reminder of what day it is. I need to omit weekends and specified school holidays. I tried something like
>   omit 5 sep #labour day
>   rem 31 aug 2005 skip *8 msg day 1
>   rem 01 sep 2005 skip *8 msg day 2
>   etc.
>   With the hopes that the next day 1 would occur on sep 9. I would much rather just omit weekends instead of using an 8 day cycle because it won't always work, but I could get that to work either. Any suggestions. BTW I am a first time poster, so please be patient if there is an answer in the archives. I couldn't find it.
> 

My current belief is that there is no (reasonable) way to do this.

The only conceivable algorithm for laying out the calendar properly is
to scan through every date in your school calendar one-by-one, skipping
weekends and holidays as you go, and keeping track of a count of days.
Remind offers a SCANFROM option, which looks promising at first, but the
syntax for expressions doesn't seem to provide a way to do any extra
computation or manipulation of state variables while that scan is being
performed.

The lack of looping constructs doesn't help either.

I did manage to get this far:

   # globally omit whatever holidays you want
   OMIT 1 Jan
   OMIT 10 Mar

   # initialize the counter
   IF !defined("daycount")
      SET daycount 1
      PRESERVE daycount
   ENDIF

   # the counter loops through a six day rotation
   FSET _next_day(x) choose(x, 2, 3, 4, 5, 6, 1)

   # every day after Jan 1 could be a candidate for triggering, but
   # omits get skipped
   IFTRIG Jan 1 2006 *1 SKIP OMIT Sat Sun
      REM [trigdate()] MSG "Day [daycount]"
      SET daycount _next_day(daycount)
   ENDIF

This will work *only* if you force remind to scan through a complete
block of days starting on some date at or before the start of the
semester, e.g. "rem -s3 Jan 1 2006" or "rem Jan 1 2006 *90".

Best I can do, maybe this will inspire someone else to come up with a
solution.  If not, I think you're stuck doing the work yourself, and
writing down a different REM statement for each day.  (Or if you're
clever, you can probably use a variation on the above script to print
out a few months worth of REM statements for you.)

Paul