GNU bug report logs - #45114
perl-mode warns about mismatched parentheses wrongly

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: 積丹尼 Dan Jacobson <jidanni <at> jidanni.org>
To: bug-gnu-emacs <at> gnu.org
Subject: perl-mode warns about mismatched parentheses wrongly
Date: Tue, 08 Dec 2020 13:45:03 +0800

$ emacs file.pl # and start typing
if(/^[^}]/) ...

During the process you will get spurious warnings about mismatched
parentheses etc.

emacs-version "27.1"

Message #8 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: bug-gnu-emacs <at> gnu.org,
 積丹尼 Dan Jacobson <jidanni <at> jidanni.org>,
 45114 <at> debbugs.gnu.org
Subject: Re: bug#45114: perl-mode warns about mismatched parentheses wrongly
Date: Tue, 08 Dec 2020 08:23:25 +0200

On December 8, 2020 7:45:03 AM GMT+02:00, "積丹尼 Dan Jacobson" <jidanni <at> jidanni.org> wrote:
> $ emacs file.pl # and start typing
> if(/^[^}]/) ...
> 
> During the process you will get spurious warnings about mismatched
> parentheses etc.
> 
> emacs-version "27.1"

This is a well documented feature.  If you don't like it, turn off blink-matching-paren.

Message #14 received at 45114 <at> debbugs.gnu.org (full text, mbox):

From: 積丹尼 Dan Jacobson <jidanni <at> jidanni.org>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: 45114 <at> debbugs.gnu.org
Subject: Re: bug#45114: perl-mode warns about mismatched parentheses wrongly
Date: Tue, 08 Dec 2020 14:38:25 +0800

>>>>> "EZ" == Eli Zaretskii <eliz <at> gnu.org> writes:

EZ> This is a well documented feature.  If you don't like it, turn off blink-matching-paren.

But that would ruin it outside of regular expressions too.

Message #17 received at 45114 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: 積丹尼 Dan Jacobson <jidanni <at> jidanni.org>
Cc: 45114 <at> debbugs.gnu.org
Subject: Re: bug#45114: perl-mode warns about mismatched parentheses wrongly
Date: Tue, 08 Dec 2020 09:04:37 +0200

On December 8, 2020 8:38:25 AM GMT+02:00, "積丹尼 Dan Jacobson" <jidanni <at> jidanni.org> wrote:
> >>>>> "EZ" == Eli Zaretskii <eliz <at> gnu.org> writes:
> 
> EZ> This is a well documented feature.  If you don't like it, turn off
> blink-matching-paren.
> 
> But that would ruin it outside of regular expressions too.

I see nothing special about regular expressions in this context.  Parens matching is useful there as well as anywhere else.

Message #20 received at 45114 <at> debbugs.gnu.org (full text, mbox):

From: 積丹尼 Dan Jacobson <jidanni <at> jidanni.org>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: 45114 <at> debbugs.gnu.org
Subject: Re: bug#45114: perl-mode warns about mismatched parentheses wrongly
Date: Tue, 08 Dec 2020 15:09:51 +0800

>>>>> "EZ" == Eli Zaretskii <eliz <at> gnu.org> writes:
EZ> I see nothing special about regular expressions in this context.  Parens matching is useful there as well as anywhere else.

/[

means we are entering characters that stand on their own, that _should
not be thought to match_ previous characters.

As I am entering the regexp, emacs should not tell me that

/[}

is wrong.

Message #23 received at 45114 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: 積丹尼 Dan Jacobson <jidanni <at> jidanni.org>
Cc: 45114 <at> debbugs.gnu.org
Subject: Re: bug#45114: perl-mode warns about mismatched parentheses wrongly
Date: Tue, 08 Dec 2020 09:14:43 +0200

On December 8, 2020 9:09:51 AM GMT+02:00, "積丹尼 Dan Jacobson" <jidanni <at> jidanni.org> wrote:
> >>>>> "EZ" == Eli Zaretskii <eliz <at> gnu.org> writes:
> EZ> I see nothing special about regular expressions in this context. 
> Parens matching is useful there as well as anywhere else.
> 
> /[
> 
> means we are entering characters that stand on their own, that _should
> not be thought to match_ previous characters.
> 
> As I am entering the regexp, emacs should not tell me that
> 
> /[}
> 
> is wrong.

I disagree.

Message #26 received at 45114 <at> debbugs.gnu.org (full text, mbox):

From: haj <at> posteo.de (Harald Jörg)
To: 積丹尼 Dan Jacobson <jidanni <at> jidanni.org>
Cc: Eli Zaretskii <eliz <at> gnu.org>, 45114 <at> debbugs.gnu.org
Subject: Re: bug#45114: perl-mode warns about mismatched parentheses wrongly
Date: Tue, 08 Dec 2020 12:13:47 +0100

積丹尼 Dan Jacobson <jidanni <at> jidanni.org> writes:

> $ emacs file.pl # and start typing
> if(/^[^}]/) ...
>
> During the process you will get spurious warnings about mismatched
> parentheses etc.
>
> emacs-version "27.1"

This is a general Emacs-ism: The warning appears in any mode, not just
in Perl mode.  So, in any environment of Perl mode: in code, but also in
strings, comments, and POD - and in character classes of a regex.
Whenever you type [}, the warning will appear (also in Gnus' message
mode, as I just experienced).

The current message texts "Mismatched parentheses" and "No matching
parenthesis found" _look_ pretty much like error messages from a
compiler, or from a syntax-aware programming mode. They always make me
wince.

I suggest to change the message texts to clarify that no effort was
taken to find out whether the mismatch is significant, like this:

   Note: no matching paren shown

Would that be acceptable?

I guess this bug can be merged with Bug#24299?
-- 
Cheers,
haj

Message #29 received at 45114 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Kangas <stefankangas <at> gmail.com>
To: Harald Jörg <haj <at> posteo.de>, 
 積丹尼 Dan Jacobson <jidanni <at> jidanni.org>
Cc: 45114 <at> debbugs.gnu.org
Subject: Re: bug#45114: perl-mode warns about mismatched parentheses wrongly
Date: Tue, 8 Dec 2020 06:03:01 -0600

forcemerge 24299 45114
thanks

haj <at> posteo.de (Harald Jörg) writes:

> I guess this bug can be merged with Bug#24299?

Yes, done.

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