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# then
Then is a minimalist plain text file calendar inspired by [When](https://www.lightandmatter.com/when/when.html). It has simple syntax optimized for the average scheduling case, but supports recurring cases more complex than most calendars. It optionally supports todo lists and deadlines but won't clutter your agenda with an empty todo list if you don't want that.
Then is a single binary with no dependencies optimized for people who want to manage events directly in their text editor rather than a TUI/GUI. You can columnize, group, sort, and archive events in your .then file(s) to keep them neat and pretty.
In terms of features and complexity, Then lies between [When](https://www.lightandmatter.com/when/when.html) and [Remind](https://dianne.skoll.ca/projects/remind/) but aims to be less verbose than either.
# .then file syntax
```
# COMMENT
DATE, EVENT
- DETAILS
```
- Lines beginning with `#` are comments used to annotate or group events together.
- Lines beginning with `-` are additional details attached to the above event.
- Blank lines are ignored.
Otherwise, a line is an event. Everything before the first comma is interpreted as the date, which is a list of conditions separated by whitespace. Parameters can be written in any order.
## Simple examples
This syntax should cover the vast majority of events
```
2025 Jan 1 00:00-03:00, Work party
2025 Jan 1 04:00, Go to bed
2025 Feb 13, Project due
Jan 1, New Year's Day (Jan 1 every year)
Tue, Taco night (Every Tuesday)
1, Mortgage due (1st of every month)
Mon Wed Fri, Submit TPS Report (Every Monday, Wednesday, or Friday)
20:00 Fri, Friday Night Magic (Every Friday at 8pm)
9am, Coffee (Every day at 9am)
, Journal (Every day)
```
## Adding details to events
Any line starting with a `-` or `+` is attached to the nearest above event. This can be used for details about an event if you don't want to put everything on one line.
```
2025 Jan 5 16:00, Doctor's Appointment
- 123 Gentoo Road, San Francisco, CA 12345
- Dr. Elias Berkins, +1 (555)-123-1234
```
## Ranges (`-`)
You can specify ranges with a dash for any condition. This works for dates if you group a day and month (and optionally year) in parentheses.
```
Mon-Fri, Work every weekday
Jan 1-7 2025, Las Vegas convention
(Jan 30 2025)-(Feb 3 2025), Ski trip
(Dec 25)-(Jan 2), Christmas vacation
```
You can omit one end of a date range to mean "before" or "after".
```
Fri -(Sep 13 2025), Every Friday before Sep 13 2025
Fri (Sep 13 2025)-, Every Friday after Sep 13 2025
```
## Logical Operators (`|`, `!`)
Parameters can be grouped with parentheses.\
`|` means OR.\
`!` means NOT.\
AND is *implied* by whitespace between conditions
```
1 | 15, Every 1st OR 15th
Fri !13, Every Fridaym, NOT the 13th
Sun !(Dec 25), Every Sunday, NOT December 25
2025 Aug 14, 2025 AND August AND the 14th
1 2, Every 1st AND 2nd (i.e. never)
```
## First/last week(s) of Month (`W`, `L`)
[N]W is the Nth set of 7 days of a month
[N]L is the Nth-from-last set of 7 days of a month
This is mostly useful for certain Holidays.
```
May 2W Sun, Mother's Day (Second Sunday of May)
May 1L Mon, Memorial Day (Last Monday of May)
1W Fri, First Friday (of every month)
```
## Modified Julian Date (`J%n+y`)
Similar to When, Then supports using a Modified Julian Date as `J`. `J` is the number of days since midnight November 17, 1858. This can be used along with the modulo operator `%` to create more complex recurring events.
```
!(J%14-5), Every other Saturday
!(J%14+2), Every other Saturday (on the other weeks)
```
Note, you can't put spaces in here like `!(J % 3)` because spaces are always interpreted as AND.
This syntax sucks but is included because it's possible. It's on the outside edge of what Then is intended to support support while still meeting the primary goal of every parameter being a condition. It's included as a last resort to allow for "every N days" when necessary.
You technically can express dates like "Repeat every 3 days between July 10-19 2025" as `>(Jul 10 2025) <(Jul 19 2025) !(J%3-2)`, but Then syntax is optimized for simple cases and gets klugey for complex recurring events.
## Deadline Recipe (TODO: Redo this entirely)
There is no distinction between a scheduled event and deadline but by using a less than operator `<` combined with some frequency you might create useful deadline reminders:
```
<(Aug 15 2025), Due 8/15 - Remind me every day
<(Aug 15 2025) Mon, Due 8/15 - Remind me every Mon
<(Aug 15 2025) J%2, Due 8/15 - Remind me every other day
>(Aug 10 2025) <(Aug 15 2025), Due 8/15 - Start daily reminders on 8/10/2025
# You technically could do this as well, although I wouldn't:
<(Aug 15 2025) ((>(Aug 1 2025) J%2) | >(Aug 10 2025)), SomeProject
- Due 8/15
- Bi-daily reminders starting 8/1
- Daily reminders starting 8/10
```
# Why would I use this?
1. You live in an open source, offline, self-hosted cabin in the woods to escape the bloated, dystopian tech world
2. You want to manage your schedule directly in your text editor
3. It's fun
Then is minimal and created to meet my personal use case. If your first thought was something about mobile phone notifications or planning how to sync Then to *another* calendar program, Then is the wrong tool and you'd be overcomplicating your workflow rather than simplifying it.
## Why would I use this over When?
I love [When](https://www.lightandmatter.com/when/when.html)! Then was created to simplify When's syntax to remove special characters from average cases.
**When**: `* * 1, Mortgage Due`\
**then**: `1, Mortgage Due`
I also added optional todo/deadline features because I use calendar events like a todo list. I might complete an event like "Change air filters" early or let it run late. I want it on my calendar until it's done, or I want it gone if I've already done it.
## Why would I use this over Remind?
I love [Remind](https://dianne.skoll.ca/projects/remind/)! It is incredibly powerful. Then syntax is shorter than Remind for average cases:
**Remind**: `REM Jan 1 MSG New Years!`\
**then**: `Jan 1, New Years!`
If you deal with events with unusual recurrence patterns or conditions, Remind is arguably nicer and inarguably much more powerful:
Every 3 days between July 10-19 2025:\
**Remind**: `REM Jul 10 2025 *3 THROUGH Jul 19 2025`\
**then**: `(Jul 10 2025)-(Jul 19 2025) !(J%3-2)`
If you have any case on the edge of what Then supports, or far beyond, you should use Remind instead.
# Alternatives
If you're interested in other plain text file calendars, I highly recommend When or Remind. It's easy to get caught up yak shaving the maximalist Emacs, so Org Mode is a bit of a beast.
- [When](https://www.lightandmatter.com/when/when.html) - The simplest text file calendar that's flexible enough for real world use.
- [Remind](https://dianne.skoll.ca/projects/remind/) - The opposite: The most powerful, programmable calendar program ever made (CLI or otherwise) but simple cases are easy and concise.
- [(Better overview here.)](https://blog.thechases.com/posts/remind/)
- [Org Mode](https://orgmode.org) - An expansive productivity playground for text with agenda features, but also a time sink trap for tinkerers.
## See Also
- [khal](https://github.com/pimutils/khal) - Similar CLI calendar, but stores calendars directly as .ics files.
- TUI calendar/productivity apps like [Calcurse](https://calcurse.org/), [calcure](https://github.com/anufrievroman/calcure), and maybe [Taskwarrior](https://taskwarrior.org/).
- [Emacs Diary](https://www.gnu.org/software/emacs/manual/html_node/emacs/Format-of-Diary-File.html) - A single agenda/diary file.
- [Plain Text Personal Organizer](https://danlucraft.com/blog/2008/04/plain-text-organizer/)
- [Calendar.txt](https://terokarvinen.com/2021/calendar-txt/) - A one-day per line text calendar idea inspired by [todo.txt](https://todotxt.org/). Very simple but high maintenence due to lack of repeating events, etc.
# License
MIT
|
