Tree-Sitter Programming Language Support in code-review-graph: Complete List and Usage Guide

The Tree-sitter parser in code-review-graph supports 25+ programming languages including Python, JavaScript, TypeScript, Go, Rust, Java, C#, Ruby, C/C++, Kotlin, Swift, PHP, and others with bundled grammars in the tree_sitter_language_pack package.

The code-review-graph project by tirth8205 leverages the Tree-sitter parsing library through the tree_sitter_language_pack package to construct language-aware code graphs for automated code review. Understanding which programming languages are supported—and how the extension-to-language mapping works—is essential for developers integrating this tool into their workflows.

Complete List of Tree-Sitter Supported Languages

The repository defines a comprehensive mapping from file extensions to language identifiers in code_review_graph/parser.py (lines 48-87). Below are all programming languages with native Tree-sitter grammar support:

Web and JavaScript Ecosystem

• JavaScript — .js, .jsx
• TypeScript — .ts, .tsx, .astro
• Vue.js — .vue (single-file components)
• Svelte — .svelte

Systems and Compiled Languages

• Go — .go
• Rust — .rs
• C / C++ — .c, .h, .cpp, .cc, .cxx, .hpp, .hh
• Zig — .zig
• Swift — .swift

JVM and Enterprise Languages

• Java — .java
• Kotlin — .kt
• Scala — .scala

Scripting and Dynamic Languages

• Python — .py
• Ruby — .rb
• PHP — .php
• Dart — .dart
• Elixir — .ex, .exs

Shell and Data Science

• Bash / Shell — .sh, .bash, .zsh, .ksh (includes Korn and Zsh variants)
• PowerShell — .ps1, .psm1, .psd1
• R — .r, .R
• Julia — .jl

Additional Supported Languages

• C# (CSharp) — .cs

• Solidity — .sol

• Objective-C — .m

• Lua — .lua

• Luau — .luau

How Language Detection Works

The EXTENSION_TO_LANGUAGE dictionary in code_review_graph/parser.py serves as the central registry for mapping file extensions to Tree-sitter grammar identifiers.

Detecting Language from File Path

from pathlib import Path
from code_review_graph.parser import EXTENSION_TO_LANGUAGE

def detect_language(file_path: str) -> str | None:
    ext = Path(file_path).suffix.lower()
    return EXTENSION_TO_LANGUAGE.get(ext)

# Usage examples

print(detect_language("example.py"))      # → "python"

print(detect_language("script.rb"))       # → "ruby"

print(detect_language("component.tsx"))   # → "typescript"

Loading and Using Tree-Sitter Parsers

For parsing source code with Tree-sitter, use the internal _load_tree_sitter_parser function:

from code_review_graph.parser import _load_tree_sitter_parser

def parse_source(grammar: str, source: bytes):
    parser = _load_tree_sitter_parser(grammar)
    if parser is None:
        raise RuntimeError(f"No Tree-sitter parser available for {grammar}")
    tree = parser.parse(source)
    return tree

# Parse a JavaScript file

with open("app.js", "rb") as f:
    tree = parse_source("javascript", f.read())
print(tree.root_node.sexp())

Important Distinction: Tree-Sitter vs. Fallback Parsers

Not all languages in the extension mapping use Tree-sitter grammars. According to the source code analysis:

• Tree-sitter supported: Languages with bundled grammars in tree_sitter_language_pack (the 25+ languages listed above).
• Regex-based fallback: Languages like Visual Basic, ReScript, and SQL lack bundled grammars and fall back to regex-based parsing.
• Custom logic: Jupyter notebooks (.ipynb) use specialized handling rather than direct Tree-sitter parsing.

Extending Language Support

The repository provides code_review_graph/custom_languages.py for adding custom Tree-sitter languages without forking the repository. This allows teams to incorporate proprietary or experimental grammars into their code review pipeline.

Testing and Validation

Two test files verify Tree-sitter language support:

Test File	Purpose
tests/test_parser_load_probe.py	Verifies Tree-sitter grammars are loadable for each supported language
tests/test_multilang.py	Contains language-specific test cases for correct parsing across the full language set

Summary

• code-review-graph supports 25+ programming languages through native Tree-sitter grammars bundled in tree_sitter_language_pack.
• Language detection relies on the EXTENSION_TO_LANGUAGE mapping in code_review_graph/parser.py (lines 48-87).
• Use _load_tree_sitter_parser(grammar) to instantiate parsers for supported languages.
• Some languages fall back to regex-based parsing; verify Tree-sitter support before relying on structural parsing features.
• Extend support through custom_languages.py for proprietary grammar requirements.

Frequently Asked Questions

What happens if I try to parse a language without Tree-sitter support?

The _load_tree_sitter_parser function returns None for unsupported grammars. Your code should handle this case or rely on the fallback regex-based parsers for languages like SQL or Visual Basic.

Can I add support for a language not in the default list?

Yes. The code_review_graph/custom_languages.py module allows you to register custom Tree-sitter grammars without modifying the core repository. Follow the module's documentation for registering new language bindings.

Does code-review-graph support Jupyter notebooks?

Jupyter notebooks (.ipynb) are handled through custom logic rather than direct Tree-sitter parsing. The tool extracts and processes code cells separately from the JSON notebook structure.

How does the project ensure parser quality across all supported languages?

The tests/test_parser_load_probe.py file programmatically verifies that every listed grammar loads successfully, while tests/test_multilang.py contains comprehensive test cases validating correct AST generation for each supported language.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
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    }
  }
}