emacs/doc
Richard Lawrence c685cf336a Add full support for iCalendar (RFC5545) data
This is a fix for Bug#74994 that replaces the existing support
in icalendar.el.  It implements a full parser, recurrence rule
and time zone calculations, diary import and export, and a
major mode with syntax highlighting for iCalendar data.  It
obsoletes most of the code in icalendar.el.

In addition to Bug#74994, the proposal to update Emacs' iCalendar
support was discussed on emacs-devel in this thread:
https://lists.gnu.org/archive/html/emacs-devel/2024-10/msg00425.html

icalendar.el pre-dates the current standard (RFC5545), contains numerous
bugs, is not well documented, and could not easily be updated or
extended; starting fresh was the simplest path to creating an iCalendar
library that other Emacs applications and packages can rely on.  It was
decided to leave icalendar.el's code in place for posterity, but declare
it obsolete.  Most of the changes in icalendar.el simply consist of such
declarations.  The old To Do list has also been deleted.

A few changes in icalendar.el, however, consist of new code for
library-wide functions and options, especially error handling.  In
particular:

* lisp/calendar/icalendar.el: Log iCalendar library errors in a single
buffer.
(icalendar-errors-mode): New mode for it.
(icalendar-uid-format): Change the default value to "%h", a hash
value (for privacy).
(icalendar-make-uid): New function, to replace 'icalendar--create-uid'.
(icalendar-debug-level, icalendar-vcalendar-prodid): New option.
(icalendar-vcalendar-version): New constant.
* lisp/calendar/icalendar.el (icalendar-import-format)
(icalendar-import-format-summary, icalendar-import-format-description)
(icalendar-import-format-location, icalendar-import-format-organizer)
(icalendar-import-format-url, icalendar-import-format-uid)
(icalendar-import-format-status, icalendar-import-format-class)
(icalendar-recurring-start-year, icalendar-export-hidden-diary-entries)
(icalendar-export-sexp-enumerate-all, icalendar-export-alarms,
icalendar-debug, icalendar--weekday-array, icalendar--dmsg)
(icalendar--get-unfolded-buffer icalendar--clean-up-line-endings)
(icalendar--rris, icalendar--read-element)
(icalendar--get-event-property, icalendar--get-event-properties)
(icalendar--get-event-property-attributes)
(icalendar--get-children, icalendar--all-events, icalendar--split-value)
(icalendar--convert-tz-offset, icalendar--parse-vtimezone)
(icalendar--get-most-recent-observance)
(icalendar--convert-all-timezones, icalendar--find-time-zone)
(icalendar--decode-isodatetime)
(icalendar--decode-isoduration, icalendar--add-decoded-times)
(icalendar--datetime-to-american-date)
(icalendar--datetime-to-european-date, icalendar--datetime-to-iso-date)
(icalendar--datetime-to-diary-date, icalendar--datetime-to-colontime)
(icalendar--get-month-number, icalendar--get-weekday-number)
(icalendar--get-weekday-numbers, icalendar--get-weekday-abbrev)
(icalendar--date-to-isodate, icalendar--datestring-to-isodate)
(icalendar--diarytime-to-isotime, icalendar--convert-string-for-export)
(icalendar--convert-string-for-import, icalendar-export-file)
(icalendar-export-region, icalendar--create-uid)
(icalendar--parse-summary-and-rest, icalendar--create-ical-alarm)
(icalendar--do-create-ical-alarm, icalendar--convert-ordinary-to-ical)
(icalendar-first-weekday-of-year, icalendar--convert-weekly-to-ical)
(icalendar--convert-yearly-to-ical, icalendar--convert-sexp-to-ical)
(icalendar--convert-block-to-ical, icalendar--convert-float-to-ical)
(icalendar--convert-date-to-ical, icalendar--convert-cyclic-to-ical)
(icalendar--convert-anniversary-to-ical, icalendar-import-file)
(icalendar-import-buffer, icalendar--format-ical-event)
(icalendar--convert-to-ical, icalendar--convert-ical-to-diary)
(icalendar--convert-recurring-to-diary)
(icalendar--convert-non-recurring-all-day-to-diary)
(icalendar--convert-non-recurring-not-all-day-to-diary)
(icalendar--add-diary-entry, icalendar-import-format-sample): Mark them
as obsolete.

In addition to the changes above, the new iCalendar library consists of
the following:

* lisp/calendar/diary-icalendar.el:
* lisp/calendar/icalendar-ast.el:
* lisp/calendar/icalendar-macs.el:
* lisp/calendar/icalendar-mode.el:
* lisp/calendar/icalendar-parser.el:
* lisp/calendar/icalendar-recur.el:
* lisp/calendar/icalendar-utils.el: New files

A few changes were made to existing files dealing with the calendar and
diary:

* lisp/calendar/calendar.el (calendar-date-from-day-of-year): New
function, extracted from calendar-goto-day-of-year.
* lisp/calendar/cal-move.el (calendar-goto-day-of-year): Use it.
* lisp/calendar/cal-dst.el (calendar-dst-find-data): Improve docstring.
* lisp/calendar/calendar.el (diary-date-insertion-form): New option.
(diary-american-date-insertion-form, diary-european-date-insertion-form)
(diary-iso-date-insertion-form): New constants.
* lisp/calendar/diary-lib.el (diary-insert-entry): Use the new
'diary-date-insertion-form' option.
(diary-time-regexp): Add FIXME to an existing comment.

The user-facing aspects of the above changes are documented in the Emacs
manual and the NEWS file:

* doc/emacs/calendar.texi (Diary Conversion): Update manual section to
describe the new importer and exporter.
* doc/emacs/emacs.texi (Detailed node listing): Update to include the
new nodes in docs/emacs/calendar.texi.
* etc/NEWS: Briefly describe the new library, major mode, and options.

The remainder of the changes apply to test files.

The following changes introduce new test files related to the new diary
importer and exporter:

* test/lisp/calendar/diary-icalendar-tests.el (Diary import and export):
Tests for diary-icalendar.  In addition to new tests for the exporter,
the existing import tests for icalendar.el have been ported here; these
use the existing iCalendar files in
test/lisp/calendar/icalendar-resources.  (A few new input .ics files
have also been added to this directory; see below.)
* test/lisp/calendar/diary-icalendar-resources: New directory containing
expected outputs for the import tests in diary-icalendar-tests.el.
(These have the same or similar names to the output files for the old
importer, in test/lisp/calendar/icalendar-resources, but different
contents.  Thus they live in a new directory.)
* test/lisp/calendar/icalendar-resources/import-legacy-function.ics: New
input file to test backward compatibility of the new importer with a
function as the value of 'icalendar-import-format', now obsolete.
* test/lisp/calendar/icalendar-resources/import-legacy-vars.ics: New
input file to test backward compatibility of the new importer with
values for options provided by icalendar.el which are now obsolete.
* test/lisp/calendar/icalendar-resources/import-with-attachment.ics: New
input file to test import of base64-encoded attachments.
* icalendar-resources/import-time-format-12hr-blank.ics: New input file
to test import with a custom value of 'diary-icalendar-time-format'.

Two other new test files provide unit tests for the main functions of
the library:

* test/lisp/calendar/icalendar-parser-tests.el (Parser): Tests for
icalendar-parser.  Most of these are derived from examples in RFC5545,
to ensure the parser implements the standard.
* test/lisp/calendar/icalendar-recur-tests.el (Recurrence rules): Tests
for icalendar-recur.  Most of these are derived from examples in RFC5545,
to ensure the recurrence rule interpreter implements the standard.

A few of the existing test files for icalendar.el have also been
modified.  Besides the specific changes mentioned below, the modified
.ics files also now use CR-LF line endings, as required by RFC5545:

* test/lisp/calendar/icalendar-tests.el (icalendar-deftest-obsolete):
New macro.
* test/lisp/calendar/icalendar-resources/import-non-recurring-all-day.ics:
Correct a malformed VALUE parameter.
* test/lisp/calendar/icalendar-resources/import-rrule-anniversary.ics:
Correct representation of a recurring event.
*
test/lisp/calendar/icalendar-resources/import-rrule-daily-with-exceptions.ics:
Add a required VALUE parameter.
* test/lisp/calendar/icalendar-resources/import-rrule-daily.ics:
* test/lisp/calendar/icalendar-resources/import-rrule-monthly-no-end.ics:
* test/lisp/calendar/icalendar-resources/import-rrule-monthly-with-end.ics:
* test/lisp/calendar/icalendar-resources/import-rrule-weekly.ics:
Correct a malformed RRULE property.
2025-12-20 13:38:02 -05:00
..
emacs Add full support for iCalendar (RFC5545) data 2025-12-20 13:38:02 -05:00
lispintro ; Fix file name in "Loading Files" doc. 2025-07-24 22:13:47 -07:00
lispref Don't change visibility of tty root frames (Bug#80032) 2025-12-20 15:12:39 +01:00
man Manual pages: use a showcase time-stamp-pattern 2025-10-16 17:29:01 -07:00
misc Document and test process filters in tramp-smb.el 2025-12-16 18:33:56 +01:00
translations Update copyright year to 2025 2025-01-02 18:39:42 +01:00