.. highlight:: go

functions5.go
=============

::

    // functions5.go

    package main

    import (
        "fmt"
    )

    func makeAdder1(n int) func(int) int {
        // n is local to makeAdder1
        f := func(a int) int { // closure
            return n + a // what n refer to?
        }
        return f
    }

    func test1() {
        add1 := makeAdder1(1)
        fmt.Println(add1(add1(3)))
    }

    func main() {
        test2()
    }

    func makeAdder2() (func() int, func() int) {
        i := 0
        add := func() int { // this is a closure because i is not local to add
            i++
            return i
        }
        get := func() int { // this is a closure because i is not local to get
            return i
        }
        // add and get are closures because they refer to a variable, i
        // in this case, not defined in the function

        return add, get // i escapes from makeAdder2
    }

    func test2() {
        incr, getter := makeAdder2()
        fmt.Println(getter())
        incr()
        incr()
        fmt.Println(getter())
    }