go generics test

example.go

package main

import (
	"errors"
	"fmt"
)

type Default[T any] interface {
	Default() T
}

type Example[T any] interface {
	Default[T]
	Init(config map[string]interface{})
}

type ExampleFactory[T Example[T]] struct {
	config map[string]interface{}
}

func (u *ExampleFactory[T]) Get() T {
	var builder T
	result := builder.Default()
	result.Init(u.config)
	return result
}

type Db struct {
	vals map[string]bool
}

func (d *Db) Default() *Db {
	return &Db {

	}
}

func (d *Db) Init(config map[string]interface{}) {
	if d == nil {
		panic(errors.New("db is nil"))
	}
	d.vals = map[string]bool{"initialized": true}
}

func main() {
	factory := &ExampleFactory[*Db]{}
	db := factory.Get()
	fmt.Printf("Initialized? %v\n", db.vals["initialized"])
}

Generics_golfing.go

package main

import (
	"errors"
	"fmt"
)

type Example interface {
	Init(config map[string]interface{})
}

type ExampleFactory[T any, PT interface { *T; Example }] struct {
	config map[string]interface{}
}

func (u *ExampleFactory[T, PT]) Get() PT {
	var result PT = new(T)
	result.Init(u.config)
	return result
}

func MakeFactory[T any, PT interface { *T; Example }]() ExampleFactory[T, PT]{
	return ExampleFactory[T, PT]{}
}

type Db struct {
	vals map[string]bool
}


func (d *Db) Init(config map[string]interface{}) {
	if d == nil {
		panic(errors.New("db is nil"))
	}
	d.vals = map[string]bool{"initialized": true}
}

func main() {
	factory := MakeFactory[Db]()
	db := factory.Get()
	fmt.Printf("Initialized? %v\n", db.vals["initialized"])
}