Generic Programming in Go

Golang released generic programming with a specific goal for developers to write a standard set of types to utilize as type parameters for functions and type structs. The syntax to write a generic function is like func F[T any] (p T){ … } that can be used to perform a common use case. Also, types can have type parameters list type O[T1, T2 any] struct.

Publication

Deep Dive into Go Generic Type Structures and Syntax

https://codingpirate.com/deep-dive-into-go-generic-type-structures-and-syntax-6f1a68e2c9c5

Repository

This repository will provide an example module written with the Go generic type structure. The following code snippet shows a middleware module to showcase the type parameter and function type arguments features in the Go generic design.

type LoginFn[P AuthParameter, R AuthClaimResponse] func(context.Context, P) (R, error)

type AuthParameter interface {
	Employee | Admin | Customer
}

type AuthClaimResponse interface {
	*GeneralClaimResponse | *AdminClaimResponse
}

func authMiddleware[P AuthParameter, R AuthClaimResponse](
	ctx context.Context,
	loginFn LoginFn[P, R], authReq P) (R, error) {
	var retry = 5
	return loginWithRetry(ctx, retry, loginFn, authReq)
}

func loginWithRetry[P AuthParameter, R AuthClaimResponse](
	ctx context.Context,
	retry int,
	loginFn LoginFn[P, R], authReq P) (R, error) {
	resp, err := loginFn(ctx, authReq)
	if err != nil {
		if retry--; retry >= 0 {
			return loginWithRetry(ctx, retry, loginFn, authReq)
		}

		return nil, err
	}

	fmt.Println("login successful ")

	return resp, nil
}

How to run the test?

go test -v -count=1 -race -cover --coverprofile=unit.out ./... && go tool cover -html=unit.out

References

License