Re: text/plain with 80 char wrap vs the flowed mime-type (whatever it is)

[Magnus Henoch <magnus.henoch@gmail.com>]

Nikolaus Rath <Nikolaus@rath.org> writes:

> On Jan 27 2016, jorge.alfaro-murillo@yale.edu (Jorge 
> A. Alfaro-Murillo) wrote: 
>> I have:  
>> 
>> #+BEGIN_SRC emacs-lisp   (add-hook 'message-mode-hook 
>> 'use-hard-newlines) #+END_SRC  
>> 
>> That allows the message to be sent with format=flowed. 
> 
> For me that breaks e.g. text pasted from a terminal or from a C 
> mode window (the pasted stuff is refilled when the message is 
> displayed by the recipient). 
> 
> Is that a general problem or something specific to my setup? 

I eventually came up with this:

  (defun my-mark-hard-newlines (beg end &rest _ignore)
    (interactive (list (point-min) (point-max)))
    (save-excursion
      (goto-char beg)
      (while (search-forward "\n" end t)
        (let ((pos (1- (point))))
          (if (get-text-property pos 'hard)
              ;; Use `copy-sequence', because display property 
              values must not be `eq'!
              (add-text-properties pos (1+ pos) (list 'display 
              (copy-sequence "⏎\n")))
            (remove-text-properties pos (1+ pos) '(display 
            nil)))))))

  (defun my-use-and-mark-hard-newlines ()
    (interactive)
    (use-hard-newlines)
    (add-hook 'after-change-functions 'my-mark-hard-newlines nil 
    t))

  (with-eval-after-load "message"
    (add-hook 'message-mode-hook 'my-use-and-mark-hard-newlines))

It doesn't fix things automatically, but it lets me see which 
newlines are hard, so I get the hint to fix code snippets manually 
before sending.

Regards,
Magnus