pointer.go

package main

import "fmt"

type Executer interface {
    Show()
}

type executer struct {
    b int 
}

func (e executer) Show() {
    fmt.Printf("Hi, b is %d", e.b)
}

type Moduler interface {
    NewRun() Executer
}

type moduler struct {
    a int 
}

func (m moduler) NewRun() Executer {
    return executer{m.a * 10} 
}

var current *Moduler

func main() {
    current = moduler{7}
    
    run := (*current).NewRun()
    run.Show()
} 

pointer_err.txt

./pointer.go:32: cannot use moduler literal (type moduler) as type *Moduler in assignment:
        *Moduler is pointer to interface, not interface

value.go

package main

import "fmt"

type Executer interface {
    Show()
}

type executer struct {
    b int 
}

func (e executer) Show() {
    fmt.Printf("Hi, b is %d", e.b)
}

type Moduler interface {
    NewRun() Executer
}

type moduler struct {
    a int 
}

func (m moduler) NewRun() Executer {
    return executer{m.a * 10} 
}

var current Moduler

func main() {
    current = moduler{7}

    run := current.NewRun()
    run.Show()
}