couleuvre 0.0.3

Vyper Language Server

Couleuvre

A lightweight Language Server for Vyper. It parses Vyper modules, extracts symbols, and supports basic navigation such as go-to-definition (including across imports), works with any Vyper version, and doesn't require Vyper to be installed.

Features

Feature	Status
Syntax Highlighting	❌ Planned
Go to Definition	✅ Supported
Go to Modules	✅ Supported
Document Symbols	✅ Supported
Workspace Symbols	❌ Planned
References	⚠️ Alpha
Hover Information	❌ Planned
Diagnostics (Errors/Warnings)	✅ Supported
Code Completion	⚠️ Alpha
Document Formatting	❌ Planned

• Automatic environment handling:
  • If the current environment already has the requested vyper version, use it directly
  • Otherwise, spin up and cache a dedicated uv-managed venv with the required vyper version

Architecture

couleuvre/
├── server.py              # LSP server (pygls) - handles client requests
├── parser.py              # Module parsing entry point
├── ast/
│   ├── parser.py          # Vyper AST → internal AST conversion
│   ├── nodes.py           # AST node dataclasses
│   ├── visitor.py         # AST visitor for symbol extraction
│   ├── environment.py     # Vyper environment abstraction
│   └── vyper_wrapper.py   # uv-managed Vyper version handling
└── features/
    ├── symbol_table.py    # Unified symbol table with metadata
    ├── symbols.py         # Document symbols (outline view)
    ├── definition.py      # Go-to-definition logic
    ├── references.py      # Find-all-references logic
    ├── resolve.py         # Symbol resolution utilities
    ├── diagnostics.py     # Semantic analysis diagnostics
    └── completion.py      # Code completion (self., module.)

Requirements

• Python >= 3.10
• uv (https://github.com/astral-sh/uv)

Installation

uv sync

Usage

• As an LSP server (from source):

uv run -m couleuvre

• Through the VSCode extension

How Vyper version is selected

• Contracts can specify the compiler version via a pragma in the source (e.g., #pragma version ^0.4.0).
• If no version is found, a default can be provided by the server based on the workspace/other files, or a diagnostic error will be shown.

Environment handling

• System Environment: If the running environment's vyper matches the contract's version, it is used directly. This allows for resolving imports by using the current environment's search paths (e.g., snekmate).
• Couleuvre Environment: Otherwise, Couleuvre creates/uses a cached virtualenv (via uv) at ~/.couleuvre/venvs/<version>/ for that version and runs Vyper with that interpreter. In this case, external imports that depend on system paths are not resolved.

Your editor should connect to the server via stdio (pygls). Point your client configuration to the above command.

Testing

uv run pytest

Alternatives

• The official Vyper Language Server (https://github.com/vyperlang/vyper-lsp) is more feature-complete but only supports Vyper >= 0.4.1 and requires Vyper to be installed in the environment.

Disclaimer

Couleuvre is in early development, use at your own risk. Couleuvre is not affiliated with the Vyper project.