syntax highlighting for c++ removes font-lock-variable-name-face

[jstaursky]

currently syntax highlighting in c++ is too much. When everything is highlighted on the page nothing becomes discernible. Currently I need to set tree-sitter-hl-face:variable to inherit from default just to regain some sanity. But then I lose variable name highlighting (during a variables declaration that is). How can I retain some features from the default font lock (such as font-lock-variable-name-face) without turning off tree-sitter?

[ubolonton]

tree-sitter-hl supports customization, as documented here. Adding this function to the major mode's hook would disable tree-sitter-hl-face:variable, and treat the font-lock-keywords-based highlighting set by the major mode as the fallback for unhighlighted texts:

(lambda ()
  (setq-local tree-sitter-hl-use-font-lock-keywords t)
  (add-function :filter-return (local 'tree-sitter-hl-face-mapping-function)
                (lambda (face)
                  (unless (memq face '(tree-sitter-hl-face:variable))
                    face))))

However, c++-mode's variable highlighting doesn't rely on font-lock-keywords alone, so the above would not work.

When everything is highlighted on the page nothing becomes discernible.

Yeah, this is a general issue with the default highlighting queries included in most grammar repositories, which seem to be geared more towards GitHub's use cases. tree-sitter-langs attempts to provide its own queries that fit Emacs better. For C/C++, they are WIP in the highlight-queries branch.

As a temporary workaround, you can override the C/C++ query files (highlights.scm) in your local installation with the WIP copies from https://github.com/ubolonton/emacs-tree-sitter/tree/highlight-queries/langs/queries.

[jstaursky]

I see. I tried the suggested WIP and still had no luck :/ to be clear I would like to go from

to

I'll try and get around to fixing this eventually and send you a pull request.

[ubolonton]

Did you copy both c/highlights.scm and cpp/highlights.scm? C++ highlighting uses both.

[jstaursky]

That did the trick! thank you, awesome project btw. Wish I knew rust so I could be helpful.

[jstaursky]

btw your missing >= and <= in your operator highlights
https://github.com/ubolonton/emacs-tree-sitter/blob/327bdec10af9600e3108d1b52d546a65d2e32c9a/langs/queries/c/highlights.scm#L40-L55

might also want to consider adding scope operator ::

[ubolonton]

That did the trick! thank you, awesome project btw. Wish I knew rust so I could be helpful.

The Rust part is actually more or less done. You can help with the Lisp part as well :)

btw your missing >= and <= in your operator highlights
might also want to consider adding scope operator ::

Yeah, I'll add those.