feat(latex): add LaTeX language support

[NandishNaik01]

Add LaTeX Syntax Highlighting Support to Arborium

Overview

This PR introduces syntax highlighting support for LaTeX (.tex) files in Arborium.

The implementation uses the [latex-lsp/tree-sitter-latex](https://github.com/latex-lsp/tree-sitter-latex) grammar at commit 7e0ecdc02926c7b9b2e0c76003d4fe7b0944f957 (MIT licensed).

Classification

• Group: group-willow

  • Added alongside other markup/document languages such as Markdown, Typst, and AsciiDoc.

• Tier: 3

  • Classified as a niche document markup language.

• External Scanner: true

  • The grammar depends on an external scanner.c implementation.

---

Highlights Query Implementation

The upstream tree-sitter-latex grammar does not ship with a queries/ directory, so highlights.scm was implemented entirely from scratch.

The query covers the following constructs:

Commands

• command_name → @function

Environments

• \begin{...} → @function.builtin
• \end{...} → @function.macro

Math Regions

• displayed_equation
• inline_formula
• math_environment

All mapped to:

• @markup.raw

Sectioning

Supports:

• \section
• \subsection
• related heading commands

Mapped using:

• @namespace
• @markup.heading

Labels & References

• curly_group_label → @label

Citations

• curly_group_text_list → @string

File Inclusion

Covers:

• \usepackage
• \input
• related include/import commands

Mapped to:

• @keyword.storage.type
• @keyword.control.import

Text Formatting

• \textbf → @markup.bold
• \textit / \emph → @markup.italic

Additional Coverage

• Comments → @comment
• Punctuation
• Operators

---

Grammar Compatibility Notes

Field names were verified directly against the grammar’s node-types.json.

Some references from Helix queries required updates due to renamed fields in the upstream grammar:

• curly_group_text → curly_group_label
• path: → paths: in bibtex_include

---

Demo & Verification

Tested locally using:

cargo xtask build --dev latex
cargo xtask serve --dev

Highlighting renders correctly across multiple themes, including:

• Tokyo Night
• Catppuccin Latte
• other bundled themes

The following syntax categories were visually verified:

• commands
• environments
• math regions
• sections/headings
• comments
• inline formatting

---

Tests

running 2 tests
test tests::test_corpus ... ok
test tests::test_grammar ... ok

test result: ok. 2 passed; 0 failed; 0 ignored

---

Files Added

langs/group-willow/latex/def/
├── arborium.yaml          # language definition
├── grammar/
│   ├── grammar.js         # from tree-sitter-latex
│   └── scanner.c          # from tree-sitter-latex src/scanner.c
├── queries/
│   └── highlights.scm     # custom highlights query
└── samples/
    └── sample.tex         # representative LaTeX sample

demo/samples/latex.tex     # live demo sample

[NandishNaik01]

Optional follow-up: indents.scm

LaTeX has a natural indentation boundary with \begin{env} / \end{env} — happy to add an indents.scm in a follow-up PR if that would be useful. No other group-willow language currently ships one, so I left it out of this PR to keep the scope minimal, but can add it if the maintainers want it.

Example of what it would look like:

(begin_command) @indent
(end_command) @outdent

Let me know!

[NandishNaik01]

Update: is now included in this PR — indents and outdents using the correct (begin) @indent.begin / (end) @indent.end capture names per arborium convention. First group-willow language to ship one.

[NandishNaik01]

Sorry Guys, I tagged you because I wasn’t sure whom to tag here. I opened this PR last week, but there haven’t been any updates on it yet. Is this project inactive now, or are updates still expected to come in?

@fasterthanlime @flying-sheep @sevki @beeb :)

[flying-sheep]

I think Amos is the only one with commit rights, and they might be on holidays or so

[NandishNaik01]

I think Amos is the only one with commit rights, and they might be on holidays or so

Thanks mate will be waiting for an update before they return is it possible u coould review the PR once Please we could resolve the comments Before Amos Returns and keep PR ready to be merged :)