| Introduction |
| ============ |
| |
| Mypy is a static type checker for Python 3 and Python 2.7. If you sprinkle |
| your code with type annotations, mypy can type check your code and find common |
| bugs. As mypy is a static analyzer, or a lint-like tool, the type |
| annotations are just hints for mypy and don't interfere when running your program. |
| You run your program with a standard Python interpreter, and the annotations |
| are treated effectively as comments. |
| |
| Using the Python 3 function annotation syntax (using the :pep:`484` notation) or |
| a comment-based annotation syntax for Python 2 code, you will be able to |
| efficiently annotate your code and use mypy to check the code for common |
| errors. Mypy has a powerful and easy-to-use type system with modern features |
| such as type inference, generics, callable types, tuple types, |
| union types, and structural subtyping. |
| |
| As a developer, you decide how to use mypy in your workflow. You can always |
| escape to dynamic typing as mypy's approach to static typing doesn't restrict |
| what you can do in your programs. Using mypy will make your programs easier to |
| understand, debug, and maintain. |
| |
| This documentation provides a short introduction to mypy. It will help you |
| get started writing statically typed code. Knowledge of Python and a |
| statically typed object-oriented language, such as Java, are assumed. |
| |
| .. note:: |
| |
| Mypy is used in production by many companies and projects, but mypy is |
| officially beta software. There will be occasional changes |
| that break backward compatibility. The mypy development team tries to |
| minimize the impact of changes to user code. |
