golang中接口赋值与方法集

接口使用疑问

golangC++

package main

import "fmt"

type user struct {
    name  string
    email string
}
type notifier interface {
    notify()
}

func (u *user) notify() {
    fmt.Printf("sending user email to %s<%s>\n",
        u.name,
        u.email)
}
func sendNotification(n notifier) {
    n.notify()
}

func main() {
    u := user{
        name:  "stormzhu",
        email: "abc@qq.com",
    }
    sendNotification(u) 
}
// compile error
// cannot use u (type user) as type notifier in argument to sendNotification:
//    user does not implement notifier (notify method has pointer receiver)

unotifier*useruseruusernotifier

sendNotification(&u) T*T

接口的定义

go

type iface struct {
    tab  *itab          // 类型信息
    data unsafe.Pointer //实际对象指针
}
type itab struct {
    inter *interfacetype // 接口类型
    _type *_type         // 实际对象类型
    fun   [1]uintptr     // 实际对象方法地址
}

C++vptrvtable

方法集

同样参考雨痕《Go语言学习笔记》第6章6.3节，书中总结的很全面：

Treceiver T*Treceiver T + *TSTreceiver T + S*STreceiver T + S + *SS*S*Treceiver T + *T + S + *S

*TT*T

uusernotifier

T*TT*T

一些例子

goerror

type error interface {
    Error() string
}

errors

// Package errors implements functions to manipulate errors.
package errors

// New returns an error that formats as the given text.
func New(text string) error {
    return &errorString{text}
}

// errorString is a trivial implementation of error.
type errorString struct {
    s string
}

func (e *errorString) Error() string {
    return e.s
}

Newerror*errorStringNew&errorString{text}errorString{text}

总结

T*T*Treceiver T + *TTreceiver T

参考