Go语言基础闭包的原理分析示例详解

// closure.Go
package main
import (
	"fmt"
	"strings"
)
func main() {
	f := closure("Http://", "com")
	fmt.Printf("%T %p \n", f, f)
	fmt.Println(f("baidu"))
	fmt.Println(f("qq"))
	fmt.Println(f("alipay.com"))
	fmt.Println("")
	f1 := closure("http://", "com")
	fmt.Printf("%T %p \n", f1, f1)
	fmt.Println(f1("baidu"))
	fmt.Println(f1("qq"))
	fmt.Println(f1("alipay.com"))
}
func closure(prefix, suffix string) func(url string) string {
	pre, suf := prefix, fmt.Sprintf(".%s", suffix)
	return func(url string) string {
		fmt.Printf("%p %p ", &pre, &suf)
		if !strings.HasPrefix(url, pre) {
			url = fmt.Sprintf("%s%s", pre, url)
		}
		if !strings.HasSuffix(url, suf) {
			url = fmt.Sprintf("%s%s", url, suf)
		}
		return url
	}
}

$ go run closure.go
func(string) string 0x493560
0xc0000301d0 0xc0000301e0 http://baidu.com
0xc0000301d0 0xc0000301e0 http://qq.com
0xc0000301d0 0xc0000301e0 http://alipay.com

func(string) string 0x493560
0xc0000302d0 0xc0000302e0 http://baidu.com
0xc0000302d0 0xc0000302e0 http://qq.com
0xc0000302d0 0xc0000302e0 http://alipay.com