SPy Language - Dev Reference

General behavior of claude code

• NEVER run tests automatically unless explicitly asked
• when asked to write a test, write just the test without trying to fix it
• avoid writing useless comments: if you need to write a comment, explain WHY the code does something instead of WHAT it does

Common Commands

• When running tests, always use the venv: e.g. `./venv/bin/pytest'
• Run all tests: pytest
• Run single test: pytest spy/tests/path/to/test_file.py::TestClass::test_function
• Run backend-specific tests: pytest -m interp or -m C or -m doppler
• Type checking: mypy
• Test shortcut: source pytest-shortcut.sh (enables p as pytest alias with tab completion)

Compile SPy Code

spy your_file.spy                 # Execute (default)
spy -C your_file.spy              # Generate C code
spy -c your_file.spy              # Compile to executable
spy -O 1 -g your_file.spy         # With optimization and debug symbols

Code Style Guidelines

• Use strict typing (mypy enforced)
• Classes: PascalCase (CompilerTest)
• Functions/methods: snake_case (compile_module())
• Constants: SCREAMING_SNAKE_CASE (ALL_BACKENDS)
• Organize imports by standard Python conventions
• Prefer specific imports: from spy.errors import SPyError
• Tests inherit from CompilerTest base class
• Use backend-specific decorators for test filtering (@only_interp, @skip_backends)

GH PR Guidelines

• When creating a PR, describe what you did, but don't include the "test plan" section.