Re: displaying octal sequences in emacs 21.3.1

[Oliver Scholz <alkibiades@gmx.de>]

Roland Winkler <Roland.Winkler@physik.uni-erlangen.de> writes:

> Eli Zaretskii <eliz@is.elta.co.il> writes:
>
>> On 2 Jul 1999, Roland Winkler wrote:
>> 
>> > My default setting for editing files is unibyte with
>> > iso-latin-1. What should I do if in certain buffers I want
>> > everything beyond 7bit asci to be displayed with the
>> > corresponding octal number?
[...]

I use this:

;; -------------------------------------------------------------------
;;; `eight-bit-graphic' and `eight-bit-control'

;; Display characters from the charsets `eight-bit-control' and
;; `eight-bit-graphic' as octal numbers in a different face.

(defface egoge-8bit-char-face
  '((t
     (:weight bold :inherit font-lock-warning-face)))
  "Face used to display characters from the charsets
`eight-bit-graphic' and `eight-bit-control'.")

(defun egoge-display-eight-bit-as-octal (&optional face)
  (let ((face-offset (if face
			 (* (face-id face)
			    (expt 2 19))
		       0))
	char)
    (dotimes (i 128)
      (setq char (+ i 128))
      (aset standard-display-table char
	    (vconcat (mapcar (lambda (c)
			       (+ face-offset c))
			     (format "\\%o" char)))))))

(unless (> emacs-major-version 21)
  (egoge-display-eight-bit-as-octal 'egoge-8bit-char-face))


It works in multibyte buffers, too.  And it works for all buffers.
IMO this is the right thing.  If you want to edit Latin-1, use a
multibyte buffer; if you want to see the octal sequences for
non-ascii, use a unibyte buffer.

[And actually I think something like this should be the default in
Emacs.]

    Oliver
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