https://docs.google.com/presentation/d/1QLDxUq5Ne_GnlZzVmINUMjGgwn9QmxUKqaBj3mi944I/edit#slide=id.gdf440fcd74_3_0

go_practice_reflect.go

package main

import (
	"errors"
	"fmt"
	"reflect"
)

var ErrNotPointerToString = errors.New("Not a pointer to a string")

func main() {
	var s string
	err := setString(&s, "hoge")
	fmt.Println(s, err == nil) // hoge true

	var n int
	err = setString(&n, "hoge")
	fmt.Println(n, err == nil) // 0 false
}

func setString(s interface{}, value string) error {
	v := reflect.ValueOf(s)

	if v.Kind() == reflect.Ptr &&
		v.Elem().Kind() == reflect.String {
		v.Elem().Set(reflect.ValueOf(value))
		return nil
	}

	return ErrNotPointerToString
}