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Re: tree-sitter: conceptional problem solvable at Emacs' level?
From: |
Po Lu |
Subject: |
Re: tree-sitter: conceptional problem solvable at Emacs' level? |
Date: |
Thu, 09 Feb 2023 16:17:27 +0800 |
User-agent: |
Gnus/5.13 (Gnus v5.13) |
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.
- tree-sitter: conceptional problem solvable at Emacs' level?, Holger Schurig, 2023/02/09
- Re: tree-sitter: conceptional problem solvable at Emacs' level?,
Po Lu <=
- Re: tree-sitter: conceptional problem solvable at Emacs' level?, Yuan Fu, 2023/02/10
- Re: tree-sitter: conceptional problem solvable at Emacs' level?, Eli Zaretskii, 2023/02/10
- Message not available
- Re: tree-sitter: conceptional problem solvable at Emacs' level?, Eli Zaretskii, 2023/02/10
- Re: tree-sitter: conceptional problem solvable at Emacs' level?, Po Lu, 2023/02/10
- Re: tree-sitter: conceptional problem solvable at Emacs' level?, Konstantin Kharlamov, 2023/02/11
- Re: tree-sitter: conceptional problem solvable at Emacs' level?, Konstantin Kharlamov, 2023/02/11
- Re: tree-sitter: conceptional problem solvable at Emacs' level?, Theodor Thornhill, 2023/02/11