Clojure Tree-Sitter Mode

clojure-ts-mode is an Emacs major mode that provides font-lock (syntax highlighting), indentation, and navigation support for the Clojure(Script) programming language, powered by the tree-sitter-clojure tree-sitter grammar.

Configuration

To see a list of available configuration options do M-x customize-group <RET> clojure-ts.

Most configuration changes will require reverting any active clojure-ts-mode buffers.

Indentation

clojure-ts-mode currently supports 2 different indentation strategies:

• semantic, the default, which tries to match the indentation of clojure-mode and cljfmt
• fixed, a simple indentation strategy outlined by Tonsky in a blog post

Set the var clojure-ts-indent-style to change it.

(setq clojure-ts-indent-style 'fixed)

Note: You can find this article comparing semantic and fixed indentation useful.

Font Locking

To highlight entire rich comment expression with the comment font face, set

(setq clojure-ts-comment-macro-font-lock-body t)

By default this is nil, so that anything within a comment expression is highlighted like regular clojure code.

Navigation and Evaluation

To make forms inside of (comment ...) forms appear as top-level forms for evaluation and navigation, set

(setq clojure-ts-toplevel-inside-comment-form t)

Rationale

clojure-mode has served us well for a very long time, but it suffers from a few long-standing problems, related to Emacs limitations baked into its design. The introduction of built-in support for Tree-sitter in Emacs 29 provides a natural opportunity to address many of them. Enter clojure-ts-mode.

Keep in mind that the transition to clojure-ts-mode won't happen overnight for several reasons:

• getting to feature parity with clojure-mode will take some time
• tools that depend on clojure-mode will need to be updated to work with clojure-ts-mode
• we still need to support users of older Emacs versions that don't support Tree-sitter

That's why clojure-ts-mode is being developed independently of clojure-mode and will one day replace it when the time is right. (e.g. 3 major Emacs version down the road, so circa Emacs 32)

You can read more about the vision for clojure-ts-mode here.

Current Status

This library is still under development. Breaking changes should be expected.

Installation

Emacs 29

This package requires Emacs 29 built with tree-sitter support from the emacs-29 branch.

If you decide to build Emacs from source there's some useful information on this in the Emacs repository:

• Emacs tree-sitter starter-guide
• Emacs install instructions.

To check if your Emacs supports tree sitter run the following (e.g. by using M-:):

(treesit-available-p)

Install clojure-ts-mode

clojure-ts-mode is available on MElPA and NonGNU ELPA. It can be installed with

(package-install 'clojure-ts-mode)

package-vc

Emacs 29 also includes package-vc-install, so you can run

(package-vc-install "https://github.com/clojure-emacs/clojure-ts-mode")

to install this package from source.

Manual installation

You can install it by cloning the repository and adding it to your load path.

git clone https://github.com/clojure-emacs/clojure-ts-mode.git

(add-to-list 'load-path "~/path/to/clojure-ts-mode/")

Once installed, evaluate clojure-ts-mode.el and you should be ready to go.

Install tree-sitter grammars

The compile tree-sitter clojure shared library must be available to Emacs. Additionally, the tree-sitter markdown_inline shared library will also be used for docstrings if available.

If you have git and a C compiler (cc) available on your system's PATH, then these steps should not be necessary. clojure-ts-mode will install the grammars when you first open a Clojure file and clojure-ts-ensure-grammars is set to t (the default).

If clojure-ts-mode fails to automatically install the grammar, you have the option to install it manually.

From your OS

Some distributions may package the tree-sitter-clojure grammar in their package repositories. If yours does you may be able to install tree-sitter-clojure with your system package manager.

If the version packaged by your OS is out of date, you may see errors in the *Messages* buffer or your clojure buffers will not have any syntax highlighting.

If this happens you should install the grammar manually with M-x treesit-install-language-grammar <RET> clojure and follow the prompts. Recommended values for these prompts can be seen in clojure-ts-grammar-recipes.

Compile From Source

If all else fails, you can attempt to download and compile manually. All you need is git and a C compiler (GCC works well).

To start, clone tree-sitter-clojure.

Then run the following code (depending on your OS) from the tree-sitter-clojure repository on your machine.

Linux

mkdir -p dist
cc -c -I./src src/parser.c -o "parser.o"
cc -fPIC -shared src/parser.o -o "dist/libtree-sitter-clojure.so"

macOS

mkdir -p dist
cc -c -I./src src/parser.c -o "parser.o"
cc -fPIC -shared src/parser.o -o "dist/libtree-sitter-clojure.dylib"

Windows

I don't know how to do this on Windows. Patches welcome!

Finally, in emacs

Then tell Emacs where to find the shared library by adding something like this to your init file:

(setq treesit-extra-load-path '( "~/path/to/tree-sitter-clojure/dist"))

OR you can move the libtree-sitter-clojure.so/libtree-sitter-clojure.dylib to a directory named tree-sitter under your user-emacs-directory (typically ~/.emacs.d on Unix systems).

Migrating to clojure-ts-mode

If you are migrating to clojure-ts-mode note that clojure-mode is still required for cider and clj-refactor packages to work properly.

After installing the package do the following.

• Check the value of clojure-mode-hook and copy all relevant hooks to clojure-ts-mode-hook.

(add-hook 'clojure-ts-mode-hook #'cider-mode)
(add-hook 'clojure-ts-mode-hook #'enable-paredit-mode)
(add-hook 'clojure-ts-mode-hook #'rainbow-delimiters-mode)
(add-hook 'clojure-ts-mode-hook #'clj-refactor-mode)

• Update .dir-locals.el in all of your Clojure projects to activate directory local variables in clojure-ts-mode.

((clojure-mode
  (cider-clojure-cli-aliases . ":test:repl"))
 (clojure-ts-mode
  (cider-clojure-cli-aliases . ":test:repl")))

Frequently Asked Questions

Does clojure-ts-mode work with CIDER?

Yes! Preliminary support for clojure-ts-mode was released in CIDER 1.14. Make sure to grab the latest CIDER from MELPA/GitHub. Note that clojure-mode is still needed for some APIs that haven't yet been ported to clojure-ts-mode.

For now, when you take care of the keybindings for the CIDER commands you use and ensure cider-mode is enabled for clojure-ts-mode buffers in your config, most functionality should already work:

(add-hook 'clojure-ts-mode-hook #'cider-mode)

Check out this article for more details.

Does clojure-ts-mode work with inf-clojure?

Currently, there is an open PR adding support for inf-clojure.

License

Copyright © 2022-2024 Danny Freeman and contributors.

Distributed under the GNU General Public License; type C-h C-c to view it.