Re: New tree-sitter mode: bison-ts-mode

[Yuan Fu <casouri@gmail.com>]

> On Sep 21, 2023, at 1:15 PM, Augustin Chéneau (BTuin) <btuin@mailo.com> wrote:
> 
> Hello,
> I'd like to propose a new tree-sitter mode for Emacs, bison-ts-mode.
> This is a major mode for GNU Bison grammar files, and it supports the embedded languages C, C++ and Java.  Bison also supports D, but this language is not yet supported in Emacs so this mode does not support it either.
> 
> Since Bison is a superset of Yacc, it should work with Yacc without modification.
> The grammar is available here: <https://gitlab.com/btuin2/tree-sitter-bison>
> 
> This mode auto-detects the embedded language in the file if the directive "%language" is set.
> 
> 
> In addition of the mode, three patches are joined (should I open a bug report for those?).
> 
> 
> The first one is to add some missing rules in c-ts-mode.  Currently there is no rule if an identifier in a declaration is on a new line.
> In these two cases, "variable_name" is not indented:
> 
> static myttype *
> variable_name;
> 
> static myttype
> variable_name;
> 
> The new behavior is the same as c-mode.
> 
> 
> 
> The second one fix an edge case with multiple languages indentation. Here is a simple example:
> 
> // language_A
>    {
>       // language_B
>    }
> // language_A
> 
> 
> Here, brackets are managed by language_A, but everything inside is managed by language_B.  Meaning that if the pointer is at the beginning of the third line (with the closing bracket), it will use language_B's indent rules.  But if the point is located on the bracket, it will use language_A's rules.
> 
> 
> 
> The third patch simply extracts java-ts-mode's feature list in a variable, to allow to reuse it.
> 
> 
> Huge thanks to Yuan Fu for his help and his amazing work with tree-sitter.

Thanks!

For now, I think we can just use the same feature names for different languages (so no need for prefixes anymore). That way, enabling a feature in the feature list would enable it for all languages. If a user desires more fine-grained control, they can use treesit-recompute-feature to enable/disable features for a particular language. (I upgraded that function in 04fd8b173bd)

Yuan