Re: Better c-ts-mode indentation when there are macros in the way

> Date: Sat, 04 Jul 2026 08:45:36 +0300
> From: Eli Zaretskii <[email protected]>
> Cc: [email protected]
> 
> > From: Björn Lindqvist <[email protected]>
> > Date: Fri, 3 Jul 2026 18:26:27 +0200
> > 
> > Hello Emacs developers!
> > 
> > Two years ago I posted about my woes getting c-ts-mode to indent
> > C code the way I wanted in the presence of preprocessor macros:
> > 
> > https://lists.gnu.org/archive/html/emacs-devel/2024-11/msg00806.html
> > 
> > To summarize, there are two problems related to how tree-sitter parses
> > preprocessor macros. The first is that #if and #else becomes part of
> > the parse tree. So tree-sitter indentation rules like (parent-is
> > "something") fails. The second problem is that preprocessor macros
> > cause incorrect parse trees of unbraced block statements:
> > 
> >     if (true)
> >     #define M
> >     printf("ooo");
> > 
> > Neither the macro nor the printf becomes the child of the if
> > statement.
> > 
> > I solved these problems by creating two functions that walks the parse
> > tree upwards to find the "real"/semantic parent of a node that I use like this:
> > 
> >     (my/c-parent-is "translation_unit") column-0 0)
> >     (my/real-c-parent-is-container my/real-c-parent-bol ,ofs)
> > 
> > Implementation here:
> > 
> >     https://gist.github.com/bjourne/63ffea0c420bf84104c3f98ca1623ea6
> > 
> > My elisp is admittedly pretty bad, but it works, and is not as brittle
> > as I thought it would be. Could something like this be added to
> > cs-ts-mode or tree-sitter?
> 
> Thanks.
> 
> Theo and Yuan, any comments on that?

Ping!