convenient. Mypy has a powerful and easy-to-use type system, supporting features such as type inference, generics, callable types, tuple types, union types, structural subtyping and more. Using mypy will make your type compatibility Stub files Creating a stub Stub file syntax Using stub file syntax at runtime Generics Defining generic classes Defining subclasses of generic classes Generic functions Generic methods name forward references for more details. Decorators Decorator functions can be expressed via generics. See Declaring decorators for more details. from typing import Any, Callable, TypeVar F = TypeVar('F'

convenient. Mypy has a powerful and easy-to-use type system, supporting features such as type inference, generics, callable types, tuple types, union types, structural subtyping and more. Using mypy will make your type compatibility Stub files Creating a stub Stub file syntax Using stub file syntax at runtime Generics Defining generic classes Defining subclasses of generic classes Generic functions Generic methods name forward references for more details. Decorators Decorator functions can be expressed via generics. See Declaring decorators for more details. from typing import Any, Callable, TypeVar F = TypeVar('F'

is a feature of Rust we haven’t talked about yet. It’s a generic type parameter, and we’ll cover generics in more detail in Chapter 10. For now, all you need to know is that means the Some variant of may store many values, but those values must all be the same type. Vectors are implemented using generics, which Chapter 10 will cover how to use in your own types. For now, all you need to know is that String { This isn’t the exact signature that’s in the standard library; there add is defined using generics. Here, we’re looking at the signature of add with concrete types substituted for the generic ones

polymorphism. §24. Type Embedding - type extension in the Go way. §25. Type-Unsafe Pointers §26. Generics - use and read composite types §27. Reflections - the reflect standard package. Some Special doesn't touch custom generics in depth. Please read the Go Generics 101 book to learn about custom generics. In addition, type parameter types (used frequently in custom generics) are deliberately ignored and comparison rules. In other words, this book doesn't consider the situations in which custom generics are involved. (The Go 101 book is still being improved frequently from time to time. Please visit

polymorphism. §24. Type Embedding - type extension in the Go way. §25. Type-Unsafe Pointers §26. Generics - use and read composite types §27. Reflections - the reflect standard package. Some Special Topics doesn't touch custom generics in depth. Please read the Go Generics 101 ? book to learn about custom generics. In addition, type parameter types (used frequently in custom generics) are deliberately ignored and comparison rules. In other words, this book doesn't consider the situations in which custom generics are involved. (The Go 101 book is still being improved frequently from time to time. Please visit