gradualtyping

Gradual typing is a programming language feature that allows developers to incrementally add static type annotations to a dynamically typed language. Instead of requiring all code to be strictly typed from the outset, gradual typing provides a way to introduce type checking gradually, often in specific modules or parts of a codebase. This approach aims to combine the flexibility and rapid prototyping capabilities of dynamic typing with the benefits of static typing, such as improved code clarity, early error detection, and enhanced tooling support.

In a gradually typed system, code that is not explicitly annotated with type information is treated as dynamically typed, meaning its types are checked at runtime. Code that *is* annotated is subject to static type checking by a type checker before runtime. This allows developers to choose where and when to apply type safety. For example, a developer might start a new project with dynamic typing for speed of development and then gradually add type annotations to critical or frequently modified sections of the code as the project matures or to improve maintainability.

The primary advantages of gradual typing include a smoother transition for developers accustomed to dynamic languages, the ability to leverage static typing benefits without a complete rewrite, and the potential for improved performance due to type inference and optimization. It also facilitates better collaboration by making code easier to understand and refactor. Tools like type checkers (e.g., MyPy for Python, Flow or TypeScript for JavaScript) are essential for implementing and enforcing gradual typing.