tree-sitter-fsharp

F# grammars for tree-sitter, packaged for Python.

The package ships two parsers:

Function	Grammar	File types
language()	implementation files	.fs, .fsx
language_signature()	signature files	.fsi

Installation

pip install tree-sitter-fsharp tree-sitter

Requires Python 3.10 or later. The tree-sitter runtime (~=0.24) is an optional dependency, also installable as an extra:

pip install "tree-sitter-fsharp[core]"

Wheels are published for the common platforms; other platforms build the extension from the bundled C sources, which needs a C11 compiler.

Usage

from tree_sitter import Language, Parser
import tree_sitter_fsharp

parser = Parser(Language(tree_sitter_fsharp.language()))

tree = parser.parse(b"let x = 1\n")
print(tree.root_node)

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

parser = Parser(Language(tree_sitter_fsharp.language_signature()))
tree = parser.parse(b"module M\nval x : int\n")

Queries

Highlight, injection, locals and tags queries ship inside the package and are exposed as lazily-read module attributes holding the query source (each is None when that query file is absent):

import tree_sitter_fsharp

source = tree_sitter_fsharp.HIGHLIGHTS_QUERY

Available: HIGHLIGHTS_QUERY, INJECTIONS_QUERY, LOCALS_QUERY and TAGS_QUERY for the implementation grammar, plus SIGNATURE_HIGHLIGHTS_QUERY and SIGNATURE_TAGS_QUERY for the signature grammar.

Type stubs (py.typed, __init__.pyi) are included.

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

MIT — see LICENSE.