Repeating dates in OmniFocus and iCal
June 30, 2008 at 11:46 PM by Dr. Drang
In trying to create a repeating OmniFocus task, I learned that its handling of repeating dates is pretty rudimentary. iCal is much better, but is still lacking some niceties that can come in handy.
My company uses an outside bookkeeper who comes to our office on the last Friday of every month to do the accounting that pays our bills, taxes, and salaries. Some paperwork needs to be done by one of the partners before her visit, and if I’m in town, I’m usually the one who does it. Last week I tried to set up an OmniFocus task to remind me of the necessary paperwork, but I was stopped short by some of OmniFocus’s limitations.
I started with what I thought was the obvious approach. I created an Accounting project and added a repeating task to get the needed paperwork ready. Two problems:
- When I’m showing Next Actions—which is my usual working Perspective—all the Next Actions appear. But the paperwork for the bookkeeper shouldn’t be done until a few days before salary checks are cut, so this task will just clutter up my view for most of the month. I may be able to get around this problem by fiddling with start dates or by scheduling an AppleScript to toggle the task status from On Hold to Active near the end of the month.
- OmniFocus’s Repeat Every setting is just too limited. It allows you repeat a task every so many days, weeks, months, or years, but it can’t handle something like “the last Friday of the month.”
This second problem is the killer, and it’s a pretty embarrassing lack of functionality. The algorithms for this kind of repetition are well established and available. Papers and books on the topic by Reingold and Dershowitz can be found here, and you can always look at the source code for the Calendar/Diary module in Emacs, or for the old BSD calendar program, which comes with OS X.
iCal has a much better repeating date implementation. I’ve used it to create an event for the bookkeeper’s visit on the morning of the last Friday of every month.
This is great for keeping track of the visits, but isn’t ideal for keeping track of my paperwork task. David Allen saith that the calendar is only for things that must be done on that day. The paperwork can be done any time in the week before the last Friday of the month and is best done a day or two before the bookkeeper’s visit.1 Since OmniFocus can’t do what I need on its own, the iCal entry will have to suffice until the OmniGroup improves its date repetition code, or until I can figure out a way to force OmniFocus to do my bidding.
I should mention here that iCal’s repeated date handling isn’t perfect. It can’t, for example, handle US election days or the US federal holiday for Christmas. Election day is not the first Tuesday in November, it’s the day after the first Monday in November. And the federal Christmas holiday—the day you get off work—is December 25 only if December 25 falls on a weekday. If it falls on a weekend, the Christmas holiday is the weekday nearest to December 25. Try doing either of these as a repeating event in iCal.
Although I have no solution now, I’m not giving up. Maybe I can use iCal’s ability to schedule AppleScripts to run a few days before an event to create an OmniFocus task telling me to get the paperwork ready. I need to dig into OmniFocus’s AppleScript library.
