Re: (error "Stack overflow in regexp matcher") and (?)wrong display of regexp in backtrace

[Alan Mackenzie <acm@muc.de>]

Hello, Stefan.

On Sun, Mar 15, 2020 at 12:35:04 -0400, Stefan Monnier wrote:
> > First of all, note the regexp, "\\(\\\\\\(.\\|\n\\)\\|[^\\\n\15]\\)*"
> >                                                             ^^^
> > In the source, the "\15" is "\r".  Why is this substitution being made
> > for the backtrace?

> The string doesn't keep track of whether it was written in the source
> code as "\r" or "\^M" or with the actual ^M character or with "\015"
> etc... so it's no wonder the printout is not exactly the same as what
> you had in the source.  I do wonder why it says \15 instead of \015, \r,
> or something else: I've almost never seen 2-digit-long octal for chars,
> (only single-digit for NUL and 3-digit for other things), so it's
> admittedly a poor choice.

A very poor choice.  What is one to make of an output such as

    [^\\\n\151]?

>         Stefan

-- 
Alan Mackenzie (Nuremberg, Germany).