+TITLE: Tree-sitter Language Bundle for Emacs
+BEGIN_HTML
+END_HTML
This is a convenient language bundle for the Emacs package [[https://github.com/emacs-tree-sitter/elisp-tree-sitter][tree-sitter]]. It serves as an interim distribution mechanism, until ~tree-sitter~ is widespread enough for language-specific major modes to incorporate its functionalities.
For each supported language, this package provides:
- Pre-compiled grammar binaries for 3 major platforms: macOS, Linux and Windows, on x86_64. In the future, ~tree-sitter-langs~ may provide tooling for major modes to do this on their own.
- An optional ~highlights.scm~ file that provides highlighting patterns. This is mainly intended for major modes that are not aware of ~tree-sitter~. A language major mode that wants to use ~tree-sitter~ for syntax highlighting should instead provide the query patterns on its own, using the mechanisms defined by [[https://emacs-tree-sitter.github.io/syntax-highlighting/interface-for-modes/][tree-sitter-hl]].
- Optional query patterns for other minor modes that provide high-level functionalities on top of ~tree-sitter~, such as code folding, evil text objects... As with highlighting patterns, major modes that are directly aware of ~tree-sitter~ should provide the query patterns on their own.
** Highlighting Queries
Note: Highlighting styles are a mattter of taste.
Highlighting query patterns for a language are in the file ~queries/
In general, try to follow what the docstrings of ~tree-sitter-hl-face:~ faces say. Most importantly:
- Definitions and uses should be differentiated:
- ~@function~ vs. ~@function.call~.
- ~@method~ vs. ~@method.call~.
- ~@type.parameter~ vs. ~@type.argument~.
- ~@variable~ and ~@variable.parameter~ should be applied only to declarations/definitions/bindings/mutations (/writes/), not usage (/reads/).
- Special faces should have high priority (placed earlier in the pattern list): ~@function.macro~, ~@type.builtin~, ~@variable.special~.
- Patterns whose internals may be highlighted should have low priority (placed towards the end). Example: strings with interpolation.
*** Mode-specific highlighting
Some languages are associated with multiple major modes. Mode-specific highlighting patterns are provided by the files ~queries/
** Building Grammars from Source Note: If you also plan to work on [[https://github.com/emacs-tree-sitter/elisp-tree-sitter#building-grammars-from-source][elisp-tree-sitter]], it might be more convenient to work with this repository as a submodule.
*** Tools and dependencies
- Install [[https://emacs-eask.github.io/][eask]].
- Install ELisp dependencies:
+begin_src bash
eask install-deps
+end_src
- Install NodeJS. It is needed to generate the grammar code from the JavaScript DSL. The recommended tool to manage NodeJS is [[https://volta.sh/][volta]].
- Install [[https://tree-sitter.github.io/tree-sitter/creating-parsers#installation][tree-sitter CLI tool]]. (Its binary can also be downloaded directly from [[https://github.com/tree-sitter/tree-sitter/releases][GitHub]].) Note: versions 0.20+ cannot be used, as they introduce [[https://github.com/tree-sitter/tree-sitter/pull/1157][a breaking change]] in binary storage location.
*** Building grammars To build a specific language's grammar, run ~script/compile~. (See the list of registered languages in [[./repos][repos/]].) For example:
+begin_src bash
script/compile rust
+end_src
To build all registered languages, and creating the bundle:
+begin_src bash
script/compile all
+end_src
*** Adding a new grammar
- Register a new submodule. For example:
+begin_src bash
git submodule add -b
-- repos/ git submodule add -b master -- https://github.com/tree-sitter/tree-sitter-rust repos/rust
+end_src
- Modify its settings in [[.gitmodules][.gitmodules]]:
+begin_src conf
update = none ignore = dirty
+end_src
- Try building and testing it. For example:
+begin_src bash
script/compile rust script/test rust
+end_src