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| author | Richard Lawrence | 2024-12-16 20:46:34 +0100 |
|---|---|---|
| committer | Eli Zaretskii | 2024-12-21 12:43:39 +0200 |
| commit | d8ffcf2fbaca158f3eed3b35cc181756a4c4878f (patch) | |
| tree | 0b131e484d54d5b659cd2d2846f96eeb0f611156 | |
| parent | faaa13ec762ddd762725d7f0eed0aced8428354a (diff) | |
| download | emacs-d8ffcf2fbaca158f3eed3b35cc181756a4c4878f.tar.gz emacs-d8ffcf2fbaca158f3eed3b35cc181756a4c4878f.zip | |
Document representation of dates in calendar.el
* lisp/calendar/calendar.el: Add a comment in file header
explaining how dates are represented.
| -rw-r--r-- | lisp/calendar/calendar.el | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/lisp/calendar/calendar.el b/lisp/calendar/calendar.el index 345687d1775..f5066c61ae2 100644 --- a/lisp/calendar/calendar.el +++ b/lisp/calendar/calendar.el | |||
| @@ -90,6 +90,16 @@ | |||
| 90 | ;; <https://doi.org/10.1002/spe.4380230404> | 90 | ;; <https://doi.org/10.1002/spe.4380230404> |
| 91 | ;; <http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.42.6421&rep=rep1&type=pdf> | 91 | ;; <http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.42.6421&rep=rep1&type=pdf> |
| 92 | 92 | ||
| 93 | ;; A note on how dates are represented: | ||
| 94 | |||
| 95 | ;; The standard format for a (Gregorian) calendar date in this file is a | ||
| 96 | ;; list of integers (MONTH DAY YEAR) -- see the functions | ||
| 97 | ;; `calendar-extract-year', `calendar-extract-month', and | ||
| 98 | ;; `calendar-extract-day'. Internally it also uses an "absolute" format | ||
| 99 | ;; which is an integer number of days since December 31, 1BC (see | ||
| 100 | ;; e.g. `calendar-absolute-from-gregorian'), and converts between | ||
| 101 | ;; different calendar scales by converting to and from the absolute | ||
| 102 | ;; format (see e.g. `calendar-iso-from-absolute' in cal-iso.el). | ||
| 93 | 103 | ||
| 94 | ;; A note on free variables: | 104 | ;; A note on free variables: |
| 95 | 105 | ||