Avoid Null pointer issues in go

README.md

used a interface called Option[T any] which helps in defining the types

main.go

package main

import "fmt"

type Class interface {
	Hello()
}
type Demo struct {
	Name string
	Roll int
}

func (d *Demo) Hello() {
	fmt.Println(d.Name, d.Roll)
}

// Option is a custom type that represents either a value or no value (None).
type Option[T any] interface {
	// isOption()
}

// func (s Some[T]) isOption() {}
// func (n None[T]) isOption() {}

type Some[T any] struct {
	Value T
}

type None[T any] struct{}

func NewSome[T any](value T) Option[T] {
	return Some[T]{Value: value}
}

func NewNone[T any]() Option[T] {
	return None[T]{}
}

func main() {

	var obj Option[Class] = None[Class]{}

	switch o := obj.(type) {
	case Some[Class]:
		fmt.Println("some value")
		o.Value.Hello()
	case None[Class]:
		fmt.Println("nil pointer found")
	default:
		fmt.Println("Invalid type")
	}

	obj = Some[Class]{Value: &Demo{Name: "dipankar", Roll: 20000}}

	switch o := obj.(type) {
	case Some[Class]:
		fmt.Println("some value")
		o.Value.Hello()
	case None[Class]:
		fmt.Println("nil pointer found")
	default:
		fmt.Println("Invalid type")
	}
}