package main

import "fmt"

func main() {
	x := 42
	fmt.Println(x)
	foo()
}

func foo() {
	// no access to x
	// this does not compile
	fmt.Println(x)
}

闭包作用域

package main

import "fmt"

func main() {
	x := 42
	fmt.Println(x)
	{
		fmt.Println(x)
		y := "The credit belongs with the one who is in the ring."
		fmt.Println(y)
	}
	fmt.Println(y) // outside scope of y
}

示例2
package main

import "fmt"

func main() {
	x := 0
	increment := func() int {
		x++
		return x
	}
	fmt.Println(increment())
	fmt.Println(increment())
}

/*
closure helps us limit the scope of variables used by multiple functions
without closure, for two or more funcs to have access to the same variable,
that variable would need to be package scope

anonymous function
a function without a name

func expression
assigning a func to a variable
*/

GOROOT=C:\Program Files\Go #gosetup

GOPATH=C:\Users\EDZ\go #gosetup

"C:\Program Files\Go\bin\go.exe" build -o C:\Users\EDZ\AppData\Local\Temp\GoLand\___2go_build_main_go__2_.exe C:\Users\EDZ\Desktop\GolangTraining\04_scope\02_block-scope\02_closure\03\main.go #gosetup

C:\Users\EDZ\AppData\Local\Temp\GoLand\___2go_build_main_go__2_.exe #gosetup

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进程 已完成，退出代码为 0


	


变量覆盖
package main

import "fmt"

func max(x int) int {
	return 42 + x
}

func main() {
	max := max(7)
	fmt.Println(max) // max is now the result, not the function
}

// don't do this; bad coding practice to shadow variables