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

[Jean-Christophe Helary]

I'm sorry, my only use for groupings was for recording a regexp and referring 
to it later, so I pretty sure I don't understand what you discuss here. But I'd 
like to...

> On May 7, 2017, at 5:03, Eli Zaretskii <address@hidden> wrote:
> 
>>>> I think regexp should be surrounded by a grouping construct, like:
>>>> 
>>>>   (concat "\\`\\(?:" (or  regexp "[ \t\n\r]+") "\\)")
>>>> 
>>>> And similarly for string-trim-right.
>>> 
>>> Rationale?
>> 
>> regexp can contain \|
> 
> Shouldn't such a regexp be surrounded by "\\(..\\)"?

So you both agree that the regexp should be surrounded by a grouping construct 
but you're arguing whether it should be a "normal" grouping or a shy grouping ?

Also,

>> This code performs string concatenation on a perfectly valid regexp
>> provided by the caller. IMO, it is this code's responsibility that the
>> result is sensible after the concatenation.
>> 
>> Are you saying this should be the caller's duty?
> 
> I'm _asking_ whether it should be the caller's duty.

How does that relate to the "shy" vs "non-shy" thing above?

Jean-Christophe