Meaning of \C-? in bracket regular expression

Meaning of \C-? in bracket regular expression

[Joe Riel]

What is the meaning of the elisp regular expression

 "[^\C-?}]"

Specifically, the "\C-?".  Is that a range? 
Then what character is \C?  
Or is it something else?

-- 
Joe Riel

Re: Meaning of \C-? in bracket regular expression

[Michael Heerdegen]

Joe Riel <joer@san.rr.com> writes:

>  "[^\C-?}]"

(info "(elisp) Ctl-Char Syntax") says that

  For historical reasons, Emacs treats the <DEL> character as the
  control equivalent of ‘?’:

       ?\^? ⇒ 127     ?\C-? ⇒ 127

Try (string-to-vector "[^\C-?}]").

So this is a question of string read syntax - there is no character "-"
in this string representing a regexp.


Michael.

Re: Meaning of \C-? in bracket regular expression

[Joe Riel]

On Mon, 28 Sep 2015 02:11:04 +0200
Michael Heerdegen <michael_heerdegen@web.de> wrote:

> Joe Riel <joer@san.rr.com> writes:
> 
> >  "[^\C-?}]"
> 
> (info "(elisp) Ctl-Char Syntax") says that
> 
>   For historical reasons, Emacs treats the <DEL> character as the
>   control equivalent of ‘?’:
> 
>        ?\^? ⇒ 127     ?\C-? ⇒ 127
> 
> Try (string-to-vector "[^\C-?}]").
> 
> So this is a question of string read syntax - there is no character "-"
> in this string representing a regexp.

Thanks, that was helpful.


-- 
Joe Riel