walk.go

package main

import "fmt"

func walkAsync(ch chan string, tree *Tree) {
	if len(tree.children) == 0 {
		ch <- tree.data
		return
	} else {
		for _, c := range tree.children {
			walkAsync(ch, c)
		}
	}
}

type Tree struct {
	data     string
	children []*Tree
}

func main() {

	var tree = new(Tree)
	tree.children = []*Tree{
		new(Tree){"a", make([]*Tree, 0)},
		*Tree{"b", make([]*Tree, 0)},
		new(Tree),
	}
	tree.children[2].children = []*Tree{
		new(Tree),
		new(Tree),
	}
	tree.children[2].children[0].data = "c"
	tree.children[2].children[1].data = "d"

	ch := make(chan string)
	go func() {
		walkAsync(ch, tree)
		close(ch)
	}()
	for c := range ch {
		fmt.Println(c)
	}
}