arborium-starlark

Starlark grammar for tree-sitter.

Deterministic, hermetic build language used by Bazel/Buck2; spec at bazel.build/rules/language.

Usage

use arborium_starlark::language;
use tree_sitter_patched_arborium::Parser;

let mut parser = Parser::new();
parser.set_language(&language()).expect("Error loading starlark grammar");

let source_code = "/* your starlark code here */";
let tree = parser.parse(source_code, None).unwrap();
println!("{}", tree.root_node().to_sexp());

For most use cases, prefer the main arborium crate:

[dependencies]
arborium = { version = "*", features = ["starlark"] }

Or use this crate directly:

[dependencies]
arborium-starlark = "*"

About Arborium

This crate is part of Arborium, a collection of tree-sitter grammars packaged as Rust crates, maintained by Amos Wenger.

This crate packages a parser.c file generated by the tree-sitter CLI. It exports a language() function returning the tree-sitter Language for starlark.

Why separate crates? Tree-sitter parsers can be large (some exceed 1MB of generated C). Splitting languages into separate crates means you only compile what you need, and parallel/incremental builds are more effective.

Build Requirements

• Rust: MSRV is 1.85.0 (Rust 2024 edition)
• C compiler: This crate compiles C code via the cc crate

Supported Targets

• All major platforms: Linux, macOS, Windows
• WebAssembly: wasm32-unknown-unknown (with custom sysroot)

Upstream Grammar

To regenerate after upstream updates:

cargo xtask gen --name starlark

Found a grammar bug? Please report it to the upstream repository.

Safety

This crate uses unsafe for FFI bindings to the tree-sitter C library. The unsafe surface is minimal and limited to what tree-sitter requires. The generated parser code is produced by tree-sitter's own code generator.

Versioning

Crate versions track Arborium releases, not upstream grammar versions. The upstream commit is recorded above. A major version bump occurs when grammar changes affect node names or structure (breaking for query consumers).

License

• Generated parser code (parser.c): MIT (from upstream grammar)
• Arborium glue code: MIT OR Apache-2.0

Contributing

• Issues: github.com/bearcove/arborium/issues
• Repository: github.com/bearcove/arborium