Re: [RFC] ox-icalendar: Unscheduled tasks & repeating tasks

[Jack Kamm <jackkamm@gmail.com>]

Ihor Radchenko <yantar92@posteo.net> writes:

> I now only have one minor concern about `org-icalendar-fold-string' when
> the original buffer contains DOS line endings. May they mess things up
> producing \r\r\n?

There are 2 issues here: what does `org-icalendar-fold-string' do when
string already contains \r, and what does `org-export-to-file' do when
`org-export-coding-system' or `buffer-file-coding-system' is dos-like.

In both cases, the patch doesn't change the existing behavior -- which
is to produce \r\r\n.

For issue 1, what `org-icalendar-fold-string' does when string already
contains \r\n, you can see that it produces \r\r\n as follows:

emacs -Q -l ox-icalendar
M-:
(org-icalendar-fold-string (org-icalendar-fold-string "Line1\nLine2"))

This is why the patch removes the calls to `org-icalendar-fold-string'
in `org-icalendar--vevent' and `org-icalendar--vtodo' -- otherwise we
would add \r multiple times to the same string.

To change this behavior of `org-icalendar-fold-string', we could
modify the patch to do:

 (defun org-icalendar-fold-string (s)
   "Fold string S according to RFC 5545."
   (replace-regexp-in-string
-   "\n" "\r\n"
+   "\r*\n" "\r\n"

which would strip out any extra \r at end of line. Another alternative
would be to use "\r?\n" instead of "\r*\n".

For the second issue -- when `org-export-coding-system' is dos (or
similar), the file created by `org-export-to-file' will contain
\r\r\n. This was already the pre-existing behavior, but note the patch
does cause a minor change here: before the patch just the main body
will have \r\r\n, but after the patch, the preamble will also have it.