tree-sitter-fsharp

F# grammars for the tree-sitter parsing library, packaged as a Rust crate.

The crate ships two parsers:

Constant	Grammar	File types
`LANGUAGE_FSHARP`	implementation files	`.fs`, `.fsx`
`LANGUAGE_SIGNATURE`	signature files	`.fsi`

Installation

cargo add tree-sitter tree-sitter-fsharp

The parsers are compiled from the bundled C sources by build.rs, so a C compiler is required. The crate itself depends only on tree-sitter-language 0.1 and does not pull in a runtime, so you choose the tree-sitter version; the crate is tested against 0.26.

Usage

let code = r#"
module M =
  let x = 0
"#;

let mut parser = tree_sitter::Parser::new();
parser
    .set_language(&tree_sitter_fsharp::LANGUAGE_FSHARP.into())
    .expect("Error loading F# parser");

let tree = parser.parse(code, None).unwrap();
assert!(!tree.root_node().has_error());

Signature files need the other grammar — it is a separate parser, not a mode of the first:

parser
    .set_language(&tree_sitter_fsharp::LANGUAGE_SIGNATURE.into())
    .expect("Error loading F# signature parser");

let tree = parser.parse("module M\nval x : int\n", None).unwrap();

Queries and node types

Query sources and the static node type descriptions are exposed as &'static str constants:

HIGHLIGHTS_QUERY, INJECTIONS_QUERY, LOCALS_QUERY, TAGS_QUERY
FSHARP_NODE_TYPES, SIGNATURE_NODE_TYPES — the contents of the respective node-types.json files

Contributing and grammar development

Grammar sources, the test corpus and the development workflow live in the repository: see the main README and AGENTS.md. Bug reports for mis-parsed F# code are welcome — reduce the snippet to a minimal example and open an issue or PR.

License