Rahu

A fast Python language server implemented in Go

Rahu provides IDE features for Python through the Language Server Protocol.

Features

• Arena-backed AST with stable node IDs for efficient memory usage
• Parallel workspace indexing with LRU caching
• Typeshed integration for accurate Python standard library types
• Support for Python 3.10 through 3.14
• Full LSP feature set: completion, hover, go-to-definition, rename, diagnostics, semantic tokens
• Embedded typeshed stubs require no external Python dependencies

Quick Start

# Build from source
git clone https://github.com/yourusername/rahu.git
cd rahu
go build ./...

# Run tests
go test ./...

# Start LSP server
go run ./cmd/lsp

Then configure your editor to use rahu.

Documentation

• Getting Started - Installation and setup
• User Guide - Features, configuration, troubleshooting
• Architecture - How rahu works internally
• Development - Contributing guide
• Roadmap - What's planned and known limitations

What's Different?

Rahu vs Pyright/Pylance:

• Native Go binary with no Node.js dependency
• Embedded typeshed requires no setup
• Focus on IDE speed over strict type checking

Rahu vs Jedi:

• Static analysis using typeshed
• LSP-native design
• Parallel workspace indexing

Current Limitations

Not yet supported:

• Lambda expressions
• Walrus operator (:=)
• Async/await
• Match statements
• Full type checking (we do inference, not enforcement)

See ROADMAP.md for complete list.

Contributing

We welcome contributions. See Contributing Guide.

Good first issues:

• Parser support for missing Python features
• Editor setup guides
• Test coverage improvements
• Documentation

License

MIT License - see LICENSE