go closure

// Go supports anonymous functions,

// which can form closures.

// Anonymous functions are useful when you want to define

// a function inline without having to name it.

package main

import “fmt”

// This function

intSeq

returns another function, which

// we define anonymously in the body of

intSeq

. The

// returned function closes over the variable

i

to

// form a closure.

func intSeq() func() int {

i := 0

return func() int {

i += 1

return i

}

}

func main() {

// We call `intSeq`, assigning the result (a function)
// to `nextInt`. This function value captures its
// own `i` value, which will be updated each time
// we call `nextInt`.
nextInt := intSeq()

// See the effect of the closure by calling `nextInt`
// a few times.
fmt.Println(nextInt())
fmt.Println(nextInt())
fmt.Println(nextInt())

// To confirm that the state is unique to that
// particular function, create and test a new one.
newInts := intSeq()
fmt.Println(newInts())