package main

import "fmt"

type Common interface {
    Something()
}


type abstractCommon struct {
    Common
    field string
}

func (c *abstractCommon) Something() {
    c.field = "prefix_" + c.field
    fmt.Println(c.field)
}

type A struct {
    abstractCommon
}

type B struct {
    abstractCommon
}

func NewA(f string) *A {
    a := A{abstractCommon{field: f}}
    return &a
}

func NewB(f string) *B {
    b := B{abstractCommon{field: f}}
    return &b
}

func main() {
    a := NewA("a")
    a.Something()

    b := NewB("b")
    b.Something()
}