From: Po Lu <luangruo@yahoo.com>
To: Holger Schurig <holgerschurig@gmail.com>
Cc: Emacs-devel@gnu.org
Subject: Re: tree-sitter: conceptional problem solvable at Emacs' level?
Date: Thu, 09 Feb 2023 16:17:27 +0800 [thread overview]
Message-ID: <87zg9n45ig.fsf@yahoo.com> (raw)
In-Reply-To: <CAOpc7mGa-kFtm7Y7GzGmOGVdPb1PAEnjPHD5yMTsRgGS0x0wmQ@mail.gmail.com> (Holger Schurig's message of "Thu, 9 Feb 2023 00:09:10 -0800")
Holger Schurig <holgerschurig@gmail.com> writes:
> Hi, I run branch emacs-29 since some time with great success. And now I
> wanted to test out tree-sitter and c++-test-mode. Unfortunately, I
> stumbled into some conceptional problems and wonder if this is actually
> solvable by Emacs, or if some would need a completely new grammar.
>
> The issue is: tree-sitter doesn't work well with C macros.
>
> I program a lot in C++/Qt. So let's look at this (valid) C++ program:
>
> -----------------------------------------------------------------------------
> #include <QObject>
>
> class Test : public QObject
> {
> Q_OBJECT
> public:
> Test() : QObject() {};
> public slots:
> void someSlot() {};
> };
> -----------------------------------------------------------------------------
>
> If have the libraries installed (e.g. qtbase5-dev on Debian), you can
> compile this perfectly.
>
> However, tree-sitter produces a garbage syntax tree:
>
> - contain some bitfield node (which isn't really there)
> - contains an error node (despite the code being compilable)
>
> And as a result, BOTH the indentation and the font-locking is wrong.
>
>
> Would I need to create a tree-sitter grammar in JavaScript that
> understands this macro-enhanced C++? That would be quite difficult.
> Or will there be a method to add some kind of tiny-preprocessor to
> c++-ts-mode, so that it can substitute "Q_OBJECT", "signals" and "slots"
> with nothing before handing things over to tree-sitter?
>
>
> In comparison, I could teach the old cc-mode about this macro-enriched
> C++ just with
>
> (c-add-style "qt-gnu"
> '("gnu" (c-access-key .
> "\\<\\(signals\\|public\\|protected\\|private\\|public
> slots\\|protected slots\\|private slots\\):")))
>
>
> I guess that a lot of C and C++ programs use macros. And if there is no
> simple way to aid tree-sitter in understanding this, then I fear
> tree-sitter enhanced modes will often be unusable on them.
My suggestion is simply to stay with CC Mode.
Parsers (without a full C preprocessor inside) can only work for
languages like Python, which cannot be enhanced with syntax-modifying
macros.
next prev parent reply other threads:[~2023-02-09 8:17 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-09 8:09 tree-sitter: conceptional problem solvable at Emacs' level? Holger Schurig
2023-02-09 8:17 ` Po Lu [this message]
2023-02-09 8:50 ` Eli Zaretskii
2023-02-09 10:13 ` Po Lu
2023-02-09 10:55 ` Eli Zaretskii
2023-02-10 7:33 ` Yuan Fu
2023-02-10 8:42 ` Eli Zaretskii
[not found] ` <CAOpc7mHX6s0B8vdDee+9FMvQejGTSL3jzgwVekS7Esg-AOf=jw@mail.gmail.com>
2023-02-10 11:48 ` Eli Zaretskii
2023-02-11 2:17 ` Po Lu
2023-02-11 6:25 ` Konstantin Kharlamov
2023-02-11 6:36 ` Konstantin Kharlamov
2023-02-11 6:51 ` Theodor Thornhill
2023-02-11 7:11 ` Konstantin Kharlamov
2023-02-11 7:53 ` Konstantin Kharlamov
2023-02-11 8:22 ` Konstantin Kharlamov
2023-02-11 8:41 ` Theodor Thornhill
2023-02-11 9:37 ` Konstantin Kharlamov
2023-02-11 10:25 ` Konstantin Kharlamov
2023-02-11 8:43 ` Eli Zaretskii
2023-04-16 19:21 ` Konstantin Kharlamov
2023-02-11 9:34 ` Ihor Radchenko
2023-02-11 10:42 ` Eli Zaretskii
2023-02-11 13:58 ` Lynn Winebarger
2023-02-09 16:25 ` Ergus
2023-02-09 20:09 ` Dmitry Gutov
2023-02-10 7:41 ` Holger Schurig
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