/*
* Go allows functions to be defined within functions.
* That is all that is happening here
* @author gtowell
* created July 20, 2021
 */
package main

import "fmt"

// main is defined as usual for functions
func main() {
	a(24)
	aa(5)
	c()
}

//the function a has a function defined within in.
//the function a is public, only a can see its internal func
func a(aa int) {
	aaa := aa * 2
	// define a function and store it in the valuable b
	// cannot use the "func b(bb int)" syntax for internal funcs
	// this cannot be recursive
	b := func(bb int) {
		bbb := bb * 10
		aaa = aaa * 2 // what happens when change = to :=
		fmt.Printf("B: aa=%v  aaa=%v bb=%v bbb=%v\n", aa, aaa, bb, bbb)
	}
	b(20)
	fmt.Printf("A: aa=%v aaa=%v\n", aa, aaa)
}

func aa(aa int) {
	aaa := aa * 2
	// define a function and store it in the valuable b
	// cannot use the "func b(bb int)" syntax for internal funcs
	// this cannot be recursive
	var b func(int) int
	b = func(bb int) int {
		if bb < 0 {
			return 10
		}
		fmt.Printf("aa_b: aa=%v  aaa=%v bb=%v\n", aa, aaa, bb)
		bb = b(bb-1) + 5
		fmt.Printf("aa_b bb: aa=%v  aaa=%v bb=%v\n", aa, aaa, bb)
		return bb
	}
	fmt.Printf("aa_b %d\n", b(aaa))
	fmt.Printf("A: aa=%v aaa=%v\n", aa, aaa)
}

// cannot use := for static assignment in global space!!
// for functions or anything else
// so c := func() {} is not allowed (!)
// but can use the var style assignment
var c = func() {
	fmt.Println("C")
}