Re: c-ts-mode: How to set indent-style in dir-locals

समीर सिंह Sameer Singh <[email protected]> writes:

> I have a .dir-locals.el file with the following content:
>
> ;;; Directory Local Variables            -*- no-byte-compile: t -*-
> ;;; For more information see (info "(emacs) Directory Variables")
>
> ((c-ts-mode . ((c-ts-mode-indent-style . bsd))))
>
> but the c files in the project does not follow the specified style for
> whatever reason. If I "describe-var" `c-ts-mode-indent-style' it says:
>
> c-ts-mode-indent-style is a variable defined in ‘c-ts-mode.el’.
>
> Its value is ‘bsd’
> Original value was ‘gnu’
> Local in buffer test.c; global value is gnu
>
> Style used for indentation.
>
> The selected style could be one of GNU, K&R, LINUX or BSD.  If the
> supplied styles don’t suffice, the value could be a function instead.
> This function takes no arguments and is expected to return a list of
> indent RULEs as described in ‘treesit-simple-indent-rules’.  Note that
> the list of RULEs doesn’t need to contain the language symbol.
>
>   This variable’s value is directory-local, set by the file
>   ‘/home/ss141309/code/project-dir/.dir-locals.el’.
>   This variable is safe as a file local variable if its value
>   satisfies the predicate ‘c-ts-indent-style-safep’.
>   This variable was introduced, or its default value was changed, in
>   version 29.1 of Emacs.
>   You can customize this variable.
>   Setting this variable directly with ‘setq’ may not take effect;
>   use either customize or ‘setopt’, or call ‘c-ts-mode--indent-style-setter’.
>

Note the last sentence in the docstring/help text, above:

>   Setting this variable directly with ‘setq’ may not take effect;
>   use either customize or ‘setopt’, or call ‘c-ts-mode--indent-style-setter’.

There does not appear to be any way to customize a user
option using a ‘.dir-locals.el’ file.  It only sets the
values of variables, which is different from setting a user
option (since Emacs 29).

C-h f setopt

   "This is like ‘setq’, but is meant for user options instead of
    plain variables.  This means that ‘setopt’ will execute any
    ‘custom-set’ form associated with VARIABLE."

When the functions ‘c-ts-mode--indent-style-setter’ or
‘c-ts-mode-set-style’ are called, they set the value of
‘c-ts-mode-indent-style’ (as your ‘.dir-locals.el’ does,
also), but also perform some other actions.  Because those
other actions are not performed when your ‘.dir-locals.el’
is read, the indentation is not working.

Two alternatives that should work for you is:

  1. Customize this option using ‘setopt’ by adding:

       (setopt c-ts-mode-indent-style 'bsd)

     to your Emacs initialization file.  

or,

   2. Customize this option using the Easy Customization
      interface in Emacs:

      M-x customize-option RET
      Customize variable: c-ts-mode-indent-style RET

      After setting the value, click on the ‘Apply and Save’
      button to save the new value to your customization file.

This will make the indentation style always in effect,
rather than only in effect for a specific directory.  You
would need to change its value again if you do not want your
setting in effect for specific files or directories.

-- 
The lyf so short, the craft so long to lerne.
- Geoffrey Chaucer, The Parliament of Birds.