Re: [PATCH v2] lisp/progmodes/etags.el improve match by string trimming

[Konstantin Kharlamov <hi-angel@yandex.ru>]

В Сб, мар 16, 2019 at 3:46 ПП (PM), Eli Zaretskii 
<eliz@gnu.org> написал:
>>  From: Konstantin Kharlamov <Hi-Angel@yandex.ru>
>>  Date: Sat, 16 Mar 2019 05:13:33 +0300
>> 
>>  Not only this improves general usability, but also works around 
>> existing
>>  bug in anjuta-tags¹
>> 
>>  1: https://gitlab.gnome.org/GNOME/anjuta/issues/8
>>  ---
>> 
>>  Sorry, I didn't test the last change on (looking-at pat) removal, it
>>  still does matching. Fixed here.
> 
> Please explain more about the original problem.

The pattern that this functions searches for determines the tag 
uniquely. But here's a catch: no programming language creates distinc 
entities (ones that end up in the tag), based only on trailing space. 
I.e. "foo()" and "    foo()   " always refer to the same thing.

So this change gives 2 improvements:
1. Emacs gonna stop failing finding a tag when someone simply 
reindented the sources
2. As a side effect, this works around a problem, when a 
tags-generating program trimmed the whitespace (the commit has a link 
to anjuta-tags bugreport about that).

 > The proposed change
> looks like it removes the support for selective-display, or am I
> missing something?
> 
> IOW, why is the regexp including the CR character a problem?
> 
> Thanks.

"CR" is part of the whitespace, so per description above comparison to 
it is simply unnecessary.