Syntax¶

Structure of a relative-date-expression to be parsed with cronspell

Expressions consist of an optional anchor at the start, from where to apply the subsequent chain of operations.

<anchor = now[UTC]> *<Operation>

Comments¶

// end-of-line comment, closed by a newline character
now[UTC]  /* inline comments */

Anchor¶

If omitted, the Anchor equates to now, zero time zone offset.

Relative datetime¶

The string now, optionally followed by a timezone name enclosed in square brackets:

now
now[Europe/Berlin]          /* any timezone identifier compatible with ZoneInfo */

Absolute datetime¶

If needed, absolute datetimes serve as anchors, too:

2024-12-30T01:13:42+05:45   /* absolute time, timezone offset as of Asia/Kathmandu */

Operation¶

Valid examples of operations, line by line:

/ month          // beginning of the month
/ sat            // beginning of the most recent saturday
/ day            // beginning of the day
+ 3 hours        // add three hours
- 1 second       // minus one second

Date-Floor¶

With Cronspell, a forward slash (/) indicates a floor operation. It follows the same logic as python math;

math.floor(3.9) == math.floor(3.0)

That said, if you do a now /sat on a saturday, it yields the same each time it is evaluated as long as the next friday has not come to an end.

Permissible expressions¶

The following expressions are recognized: