loppers 0.1.0

Extract source file skeletons using tree-sitter queries

Loppers

Simplified library for extracting source file skeletons using tree-sitter queries.

Removes function implementations while preserving structure and signatures.

Requires tree-sitter >= 0.25

Features

• ✅ Functions & Methods - All regular and async functions
• ✅ Constructors - Python __init__, Java/TS constructor()
• ✅ Arrow Functions - JavaScript/TypeScript arrow functions
• ✅ Class Methods - Instance, static, class methods
• ✅ Docstrings - Python docstrings preserved
• ✅ Decorators - Preserved (Python, Java)
• ✅ Type Hints - Fully typed library
• ✅ 11 Languages - Python, JS/TS, Java, Go, Rust, C/C++, C#, Ruby, PHP

See HANDLED_CASES.md for comprehensive list of supported cases.

Installation

With uv (recommended)

# Install from source
uv pip install -e .

# Or sync with pyproject.toml
uv sync

# Install with dev dependencies
uv sync --extra dev

With pip

pip install tree-sitter>=0.25.0 tree-sitter-language-pack

Usage

from loppers import extract

source: str = '''
def calculate(x: int, y: int) -> int:
    """Calculate sum."""
    result: int = x + y
    return result
'''

skeleton: str = extract(source, "python")
print(skeleton)

Output:

def calculate(x: int, y: int) -> int:
    """Calculate sum."""

Supported Languages

• Python (with docstring preservation)
• JavaScript / TypeScript (including arrow functions)
• Java (including constructors)
• Go
• Rust
• C / C++
• C#
• Ruby
• PHP

Development

Setup

# Create environment and install dev dependencies
uv sync --extra dev

Testing with pytest

# Run all tests
uv run pytest

# Run with verbose output
uv run pytest -v

# Run with coverage
uv run pytest --cov=loppers --cov-report=html

# Run specific test
uv run pytest test_loppers.py::TestSkeletonExtractor::test_python_extraction

# Run with markers
uv run pytest -m "not slow"

Code Quality with ruff

# Check code style
uv run ruff check .

# Fix issues automatically
uv run ruff check . --fix

# Format code (included in check --fix)
uv run ruff format .

# Run all checks
uv run ruff check . && uv run ruff format .

How It Works

Uses tree-sitter queries to find and remove function/method body nodes while keeping:

• Function signatures
• Class definitions
• Import statements
• Python docstrings
• Comments

API

extract(source_code: str, language: str) -> str

Extract skeleton from source code.

Args:

• source_code: Source code to process
• language: Programming language

Returns: Skeleton with implementations removed

Raises:

• ValueError: If language not supported

SkeletonExtractor(language: str)

Create extractor for a specific language.

Methods:

• extract(source_code: str) -> str: Extract skeleton

Raises:

• ValueError: If language not supported

Adding Languages

To add a new language, extend LANGUAGE_CONFIGS with a tree-sitter query:

LANGUAGE_CONFIGS["newlang"] = LanguageConfig(
    name="newlang",
    body_query="(function_definition body: (block) @body)",
)

Find the correct query for your language by exploring the tree-sitter grammar.

Type Hints

This project uses comprehensive type hints throughout. All functions are fully typed.

# Example of type hints in use
def extract(source_code: str, language: str) -> str:
    """Extract skeleton from source code."""
    extractor: SkeletonExtractor = SkeletonExtractor(language)
    return extractor.extract(source_code)

Configuration Files

• pyproject.toml: Project metadata, dependencies, pytest, and ruff configuration
• HANDLED_CASES.md: Comprehensive list of supported cases
• .gitignore: Git ignore rules
• UV_GUIDE.md: uv package manager quick reference
• DEVELOPMENT.md: Detailed development guide

.
├── loppers.py              # Core library (typed)
├── examples.py             # Usage examples (typed)
├── test_loppers.py         # Unit tests (typed)
├── pyproject.toml          # uv/pip + pytest + ruff config
├── .gitignore              # Git ignore rules
├── README.md               # This file
├── UV_GUIDE.md             # uv quick reference
└── requirements.txt        # Legacy requirements

tree-sitter API Changes (>= 0.25)

Key changes in the code for tree-sitter >= 0.25:

• Language wrapping: Language(tree_sitter_language_pack.get_language(...))
• Parser language assignment: parser.language = lang (property instead of set_language())

References

• tree-sitter
• tree-sitter-language-pack
• uv - Python packaging
• pytest
• ruff