scala-ts-mode is a tree-sitter based GNU Emacs major mode built on top of the Emacs 29+ treesit library. It provides the following features in a Scala buffer-
- efficient font-locking using tree-sitter
imenuintegration- indentation support using tree-sitter
The major-mode is mostly complete and in a very usable state currently. Improvements will come as I find bugs, edge cases, more use cases or the upstream grammar evolves.
To use the package, the following dependencies are required.
- GNU Emacs 29+, built with support for tree-sitter.
- tree-sitter grammar for Scala (you can use the
treesit-install-language-grammarfunction for installing it.)
To install the package, you can use any Emacs package manager of your choice, to pull the package either from MELPA or source. For example, with straight.el, you can do the following -
(straight-use-package 'scala-ts-mode)(straight-use-package '(scala-ts-mode :type git :host github :repo "KaranAhlawat/scala-ts-mode"))Then, you can simply call scala-ts-mode in a Scala buffer.
You may wish to customize treesit-font-lock-level, using M-x customize-variable or by adding a line such as this to your user init file:
(setq treesit-font-lock-level 4)The default font lock level is 3. At that level, not as many constructs are highlighted as you might like. Increasing it to 4 results in richer highlighting.
Some versions of Emacs aren’t set up with an Eglot that knows which LSP server to use for scala-ts-mode.
This code can be in init.el before loading Eglot to tell it to use the same function for scala-ts-mode that it does for scala-mode.
(add-to-list 'eglot-server-programs
`((scala-mode scala-ts-mode)
. ,(alist-get 'scala-mode eglot-server-programs)))Contributions are welcome! These can be in the form of PRs, Issues, or any other way you can think of. This is my first package, so please don’t hold back :)
GPLv3