Re: How switch from escaped octal character code to escaped HEX?

[Oleksandr Gavenko]

On 03.01.2011 6:23, Stefan Monnier wrote:
> > > When Emacs find that byte that does
> > > not correspond to any specific displayable character it display
> > > octal codes instead, like: \276 (and with different color).
> > >
> > > This is useful, but I prefer HEX base instead octal.
>
> There is no direct/easy way to do it.
> But you can do it by adding the corresponding 128 entries to the
> standard-display-table.
>
> E.g.
>
>     (setq standard-display-table (make-display-table))
>     (aset standard-display-table (unibyte-char-to-multibyte 131)
>                                  [?\\ ?x ?8 ?3])
>     (aset standard-display-table (unibyte-char-to-multibyte 132)
>                                  [?\\ ?x ?8 ?4])
>
> Should make the bytes 131 and 132 be displayed as \x83 and \x84 rather
> than \203 and \204.
Thanks Stefan for tips.

I read docs for 'buffer-display-table'. Here said:

  For example, (aset buffer-display-table ?X [?Y]) tells Emacs
  to display a capital Y instead of each X character.

So if in one encoding (cp1251) letter - й, in another (row-text) - \351.

I set:

(aset standard-display-table (unibyte-char-to-multibyte ?\xe9) [?\\ ?x 
?e ?9])

but in cp1251 it properly displayed like й, in row-text - \xe9. I 
afraid that it
in all case must be \xe9, but not. This is nice!


With this behavior I make I wont. Only one problem.

In GUI Emacs octal codes colorized (some thins red color,
C-u C-x = don't give font properties).

New hex values is not colorized. How make this?


PS. To make all 128 chars in hex I wrote:

(setq standard-display-table (make-display-table))
(let ( (i ?\x80) hex hi low )
  (while (<= i ?\xff)
    (setq hex (format "%x" i))
    (setq hi (elt hex 0))
    (setq low (elt hex 1))
    (aset standard-display-table (unibyte-char-to-multibyte i) (vector 
?\\ ?x hi low))
    (setq i (+ i 1))
    ) )

PPS. Noel Evans send to me private mail where hi suggest:

(setq read-quoted-char-radix 16)

I already have this settings a lot of years. It allow you type byte in 
hex: C-q 9 9 RET.