video: https://youtu.be/5IKcPMJXkKs?t=1091 and blog: https://medium.com/capital-one-developers/closures-are-the-generics-for-go-cb32021fb5b5 playground: https://play.golang.org/p/g2KBbxCc35c

golang generics with side effects

package main

import (
	"fmt"
)

type Employee struct {
	Id   int
	Name string
}

type Person struct {
	Age  int
	Name string
}

type PetOwner struct {
	Person
	Pet string
}

func FilterPerson(ps []Person, name string) []Person {
	var out []Person
	for _, v := range ps {
		if v.Name == name {
			out = append(out, v)
		}
	}
	return out
}

func NameFilter(length int, name string,
	nameFinder func(int) string,
	populator func(int)) {
	for i := 0; i < length; i++ {
		if nameFinder(i) == name {
			populator(i)
		}
	}
}

func main() {
	fmt.Println("Hello, playground")

	peeps := []Person{
		Person{27, "samantha"},
		Person{37, "tom"},
	}

	var nameFilteredPersons []Person
	NameFilter(len(peeps), "tom",
		func(i int) string {
			return peeps[i].Name
		}, func(i int) {
			nameFilteredPersons = append(nameFilteredPersons, peeps[i])
		})

	fi := FilterPerson(peeps, "tom")
	fmt.Println(fi)
	fmt.Println("generics with side effects!")
	fmt.Println(nameFilteredPersons)
}