bug#27270: display-raw-bytes-as-hex generates ambiguous output for Emacs strings

[Paul Eggert]

On 06/06/2017 10:17 PM, Eli Zaretskii wrote:

> What do you mean by "Emacs strings"?

I meant that if I prefer hex to octal for buffer escapes, then when I 
type this into *scratch*:

  (format "J%cK" ?\u0080) C-j

I almost surely would prefer to see the result displayed as hexadecimal 
than as "J\200K" (the current behavior). People who prefer hex in one 
place are quite likely to prefer it in the other.

Here's another suggestion for the buffer problem: separate problematic 
character pairs by "\ " in the buffer display. That way, my test case 
would be displayed this way in a buffer;

  x\x90\ 5y

and this will work as expected when cut and pasted into a string, due to 
the backslash-space syntax already supported for strings. This buffer 
syntax would be less confusing than the "x\x905y" syntax that is 
currently used. Under this approach character pair XY is considered to 
be problematic if X is displayed with a hexadecimal escape and Y is a 
hexadecimal digit.