Re: Trimming strings, /emacs/lisp/emacs-lisp/subr-x.el modification

[Eli Zaretskii]

> From: Andreas Schwab <address@hidden>
> Cc: Eli Zaretskii <address@hidden>,  Michael Heerdegen
>  <address@hidden>,  Mark Oteiza <address@hidden>,
>   address@hidden,  Johan Bockgård <address@hidden>,
>   address@hidden
> Date: Tue, 09 May 2017 18:37:47 +0200
> 
> > Ok, so we agree that we don't add \\( \\) to the regexp and that we expect 
> > the caller to send a correct regexp as is the case for split-string, is 
> > that correct ?
> 
> If you want to modify a regexp you need to make sure to preserve its
> semantics.

Can you give an example of a regexp whose semantics might change by
adding \\(..\\)?